diff --git a/.github/workflows/contributor.yml b/.github/workflows/contributor.yml
index 627d00ab3..bbc00ce97 100644
--- a/.github/workflows/contributor.yml
+++ b/.github/workflows/contributor.yml
@@ -11,7 +11,7 @@ on:
 jobs:
   Test:
     name: "'docs/CONTRIBUTORS' was signed"
-    runs-on: ubuntu-20.04
+    runs-on: ubuntu-22.04
     steps:
     - uses: actions/checkout@v2
     - run: test_regress/t/t_dist_contributors.pl
diff --git a/Changes b/Changes
index ba4c752ba..bd1720f09 100644
--- a/Changes
+++ b/Changes
@@ -24,9 +24,21 @@ Verilator 5.001 devel
 Verilator 4.227 devel
 ==========================
 
+**Announcement:**
+
+* The next release is anticipated primere Verilator Version 5.  Please
+  consider beta-testing the github 'develop-v5' branch, which will soon
+  merge into the github 'master' branch (#3383).
+
 **Minor:**
 
-Fix crash in gate optimization of circular logic (#3543). [Bill Flynn]
+* Support IEEE constant signal strengths (#3601). [Ryszard Rozak/Antmicro]
+* Add --main to generate main() C++ (previously was experimental only).
+* Fix thread saftey in SystemC VL_ASSIGN_SBW/WSB (#3494) (#3513). [Mladen Slijepcevic]
+* Fix crash in gate optimization of circular logic (#3543). [Bill Flynn]
+* Fix arguments in non-static method call (#3547) (#3582). [Gustav Svensk]
+* Fix default --mod-prefix when --prefix is repeated (#3603). [Geza Lore]
+* Fix typedef'ed class conversion to boolean (#3616). [Aleksander Kiryk]
 
 
 Verilator 4.226 2022-08-31
@@ -46,7 +58,7 @@ Verilator 4.226 2022-08-31
 * Fix incorrect tristate logic (#3399) [shareefj, Vighnesh Iyer]
 * Fix incorrect bit op tree optimization (#3470). [algrobman]
 * Fix bisonpre for MSYS2 (#3471).
-* Fix max memory usage (#3483). [Kamil Rakoczy]
+* Fix max memory usage (#3483). [Kamil Rakoczy/Antmicro]
 * Fix empty string arguments to display (#3484). [Grulfen]
 * Fix table misoptimizing away display (#3488). [Stefan Post]
 * Fix unique_ptr memory header for MinGW64 (#3493).
@@ -57,7 +69,7 @@ Verilator 4.226 2022-08-31
 * Fix segfault exporting non-existant package (#3535).
 * Fix void-cast queue pop_front or pop_back (#3542) (#3364). [Drew Ranck]
 * Fix case statement comparing string literal (#3544). [Gustav Svensk]
-* Fix === with some tristate constants (#3551). [Ryszard Rozak]
+* Fix === with some tristate constants (#3551). [Ryszard Rozak/Antmicro]
 * Fix converting subclasses to string (#3552). [Arkadiusz Kozdra/Antmicro]
 * Fix --hierarchical with order-based pin connections (#3583) (#3585). [Kelin9298]
 
diff --git a/Makefile.in b/Makefile.in
index fc9b6b1a9..08271b047 100644
--- a/Makefile.in
+++ b/Makefile.in
@@ -391,10 +391,10 @@ yapf:
 FLAKE8 = flake8
 FLAKE8_FLAGS = \
 	--extend-exclude=fastcov.py \
-	--ignore=E123,E129,E251,E501,W503,W504,E701
+	--ignore=E123,E129,E251,E402,E501,W503,W504,E701
 
 PYLINT = pylint
-PYLINT_FLAGS = --disable=R0801
+PYLINT_FLAGS = --score=n --disable=R0801
 
 lint-py:
 	-$(FLAKE8) $(FLAKE8_FLAGS) $(PY_PROGRAMS)
diff --git a/README.rst b/README.rst
index 8dd636245..d46296d02 100644
--- a/README.rst
+++ b/README.rst
@@ -28,7 +28,7 @@ Welcome to Verilator
      - |Logo|
    * - |verilator multithreaded performance|
      - **Fast**
-        * Outperforms many commercial simulators
+        * Outperforms many closed-source commercial simulators
         * Single- and multi-threaded output models
    * - **Widely Used**
         * Wide industry and academic deployment
@@ -55,20 +55,19 @@ performing lint checks, and optionally inserting assertion checks and
 coverage-analysis points. It outputs single- or multi-threaded .cpp and .h
 files, the "Verilated" code.
 
-The user writes a little C++/SystemC wrapper file, which instantiates the
-"Verilated" model of the user's top level module. These C++/SystemC files
-are then compiled by a C++ compiler (gcc/clang/MSVC++). Executing the
-resulting executable performs the design simulation. Verilator also
-supports linking Verilated generated libraries, optionally encrypted, into
-other simulators.
+These Verilated C++/SystemC files are then compiled by a C++ compiler
+(gcc/clang/MSVC++), optionally along with a user's own C++/SystemC wrapper
+file to instantiate the Verilated model. Executing the resulting executable
+performs the design simulation. Verilator also supports linking Verilated
+generated libraries, optionally encrypted, into other simulators.
 
 Verilator may not be the best choice if you are expecting a full featured
-replacement for Incisive, ModelSim/Questa, VCS or another commercial
-Verilog simulator, or if you are looking for a behavioral Verilog simulator
-e.g. for a quick class project (we recommend `Icarus Verilog`_ for this.)
-However, if you are looking for a path to migrate SystemVerilog to C++ or
-SystemC, or your team is comfortable writing just a touch of C++ code,
-Verilator is the tool for you.
+replacement for a closed-source Verilog simulator, need SDF annotation,
+mixed-signal simulation, or are doing a quick class project (we recommend
+`Icarus Verilog`_ for classwork.)  However, if you are looking for a path
+to migrate SystemVerilog to C++/SystemC, or want high speed simulation of
+synthesizable designs containing limited verification constructs, Verilator
+is the tool for you.
 
 
 Performance
@@ -85,9 +84,11 @@ multithreading (yielding 200-1000x total over interpreted simulators).
 
 Verilator has typically similar or better performance versus the
 closed-source Verilog simulators (Carbon Design Systems Carbonator,
-Modelsim, Cadence Incisive/NC-Verilog, Synopsys VCS, VTOC, and Pragmatic
-CVer/CVC). But, Verilator is open-sourced, so you can spend on computes
-rather than licenses. Thus Verilator gives you the best cycles/dollar.
+Modelsim/Questa, Cadence Incisive/NC-Verilog, Synopsys VCS, VTOC, and
+Pragmatic CVer/CVC). But, Verilator is open-sourced, so you can spend on
+computes rather than licenses. Thus Verilator gives you the best
+cycles/dollar.
+
 
 Installation & Documentation
 ============================
diff --git a/bin/verilator b/bin/verilator
index 703a09ed4..b68812d61 100755
--- a/bin/verilator
+++ b/bin/verilator
@@ -344,6 +344,7 @@ detailed descriptions of these arguments.
     --main                      Generate a main C++ file
     --make <build-tool>         Generate scripts for specified build tool
      -MAKEFLAGS <flags>         Arguments to pass to make during --build
+    --main                      Generate C++ main()
     --max-num-width <value>     Maximum number width (default: 64K)
     --Mdir <directory>          Name of output object directory
     --MMD                       Create .d dependency files
diff --git a/bin/verilator_difftree b/bin/verilator_difftree
index 3e8315691..d7c65a28e 100755
--- a/bin/verilator_difftree
+++ b/bin/verilator_difftree
@@ -38,7 +38,7 @@ def diff_dir(a, b):
 
     anyfile = False
     for base in sorted(files.keys()):
-        if (not 'a' in files[base]) or (not 'b' in files[base]):
+        if ('a' not in files[base]) or ('b' not in files[base]):
             continue
         a = files[base]['a']
         b = files[base]['b']
diff --git a/bin/verilator_gantt b/bin/verilator_gantt
index 616af30dc..03a7a16af 100755
--- a/bin/verilator_gantt
+++ b/bin/verilator_gantt
@@ -149,7 +149,8 @@ def report():
     for thread in Threads:
         # Make potentially multiple characters per column
         for start in Threads[thread]:
-            if not Threads[thread][start]: continue
+            if not Threads[thread][start]:
+                continue
             cpu = Threads[thread][start]['cpu']
             elapsed = Threads[thread][start]['end'] - start
             if cpu not in Global['cpus']:
diff --git a/ci/ci-install.bash b/ci/ci-install.bash
index 4f61f06c4..2e7325cea 100755
--- a/ci/ci-install.bash
+++ b/ci/ci-install.bash
@@ -19,6 +19,10 @@ set -x
 
 cd $(dirname "$0")/..
 
+# Avoid occasional cpan failures "Issued certificate has expired."
+export PERL_LWP_SSL_VERIFY_HOSTNAME=0
+echo "check_certificate = off" >> ~/.wgetrc
+
 fatal() {
   echo "ERROR: $(basename "$0"): $1" >&2; exit 1;
 }
diff --git a/docs/CONTRIBUTORS b/docs/CONTRIBUTORS
index aa66209c5..7a800bab7 100644
--- a/docs/CONTRIBUTORS
+++ b/docs/CONTRIBUTORS
@@ -82,6 +82,7 @@ Michael Killough
 Michaël Lefebvre
 Mike Popoloski
 Miodrag Milanović
+Mladen Slijepcevic
 Morten Borup Petersen
 Mostafa Gamal
 Nandu Raj
diff --git a/docs/guide/exe_verilator.rst b/docs/guide/exe_verilator.rst
index 25891aa32..ce2140c7a 100644
--- a/docs/guide/exe_verilator.rst
+++ b/docs/guide/exe_verilator.rst
@@ -716,6 +716,15 @@ Summary:
    (e.g. ``-MAKEFLAGS -l -MAKEFLAGS -k``). Use of this option should not be
    required for simple builds using the host toolchain.
 
+.. option:: --main
+
+   Generates a top-level C++ main() file that supports parsing arguments,
+   but does not drive any inputs.  This is sufficient to use for top-level
+   SystemVerilog designs that has no inputs, and does not need the C++ to
+   do any time advancement.
+
+   Implies :vlopt:`--cc` if no other output mode was provided.
+
 .. option:: --max-num-width <value>
 
    Set the maximum number literal width (e.g. in 1024'd22 this it the
diff --git a/docs/guide/simulating.rst b/docs/guide/simulating.rst
index 01dd7f844..7209a0a19 100644
--- a/docs/guide/simulating.rst
+++ b/docs/guide/simulating.rst
@@ -7,9 +7,9 @@
 Simulating (Verilated-Model Runtime)
 ************************************
 
-This section describes items related to simulating, that using a Verilated
-model's executable.  For the runtime arguments to a simulated model, see
-:ref:`Simulation Runtime Arguments`.
+This section describes items related to simulating, that is, the use of a
+Verilated model's executable.  For the runtime arguments to a simulated
+model, see :ref:`Simulation Runtime Arguments`.
 
 
 .. _Benchmarking & Optimization:
diff --git a/examples/make_protect_lib/sim_main.cpp b/examples/make_protect_lib/sim_main.cpp
index b3096b4c5..fefcb0c5a 100644
--- a/examples/make_protect_lib/sim_main.cpp
+++ b/examples/make_protect_lib/sim_main.cpp
@@ -32,7 +32,7 @@ int main(int argc, char** argv, char** env) {
     // When tracing, the contents of the secret module will not be seen
     VerilatedVcdC* tfp = nullptr;
     const char* flag = contextp->commandArgsPlusMatch("trace");
-    if (flag && 0 == strcmp(flag, "+trace")) {
+    if (flag && 0 == std::strcmp(flag, "+trace")) {
         contextp->traceEverOn(true);
         VL_PRINTF("Enabling waves into logs/vlt_dump.vcd...\n");
         tfp = new VerilatedVcdC;
diff --git a/examples/make_tracing_sc/sc_main.cpp b/examples/make_tracing_sc/sc_main.cpp
index 93861ceea..3d3cb1392 100644
--- a/examples/make_tracing_sc/sc_main.cpp
+++ b/examples/make_tracing_sc/sc_main.cpp
@@ -89,7 +89,7 @@ int sc_main(int argc, char* argv[]) {
     // and if at run time passed the +trace argument, turn on tracing
     VerilatedVcdSc* tfp = nullptr;
     const char* flag = Verilated::commandArgsPlusMatch("trace");
-    if (flag && 0 == strcmp(flag, "+trace")) {
+    if (flag && 0 == std::strcmp(flag, "+trace")) {
         cout << "Enabling waves into logs/vlt_dump.vcd...\n";
         tfp = new VerilatedVcdSc;
         top->trace(tfp, 99);  // Trace 99 levels of hierarchy
diff --git a/include/verilated_funcs.h b/include/verilated_funcs.h
index a7c3fcc73..8bcef8019 100644
--- a/include/verilated_funcs.h
+++ b/include/verilated_funcs.h
@@ -448,10 +448,17 @@ static inline void VL_ASSIGNBIT_WO(int bit, WDataOutP owp) VL_MT_SAFE {
     { \
         const int words = VL_WORDS_I(obits); \
         sc_biguint<(obits)> _butemp = (svar).read(); \
-        for (int i = 0; i < words; ++i) { \
-            int msb = ((i + 1) * VL_IDATASIZE) - 1; \
-            msb = (msb >= (obits)) ? ((obits)-1) : msb; \
-            (owp)[i] = _butemp.range(msb, i * VL_IDATASIZE).to_uint(); \
+        uint32_t* chunk = _butemp.get_raw(); \
+        int32_t lsb = 0; \
+        while (lsb < obits - BITS_PER_DIGIT) { \
+            const uint32_t data = *chunk; \
+            ++chunk; \
+            _vl_insert_WI(owp.data(), data, lsb + BITS_PER_DIGIT - 1, lsb); \
+            lsb += BITS_PER_DIGIT; \
+        } \
+        if (lsb < obits) { \
+            const uint32_t msb_data = *chunk; \
+            _vl_insert_WI(owp.data(), msb_data, obits - 1, lsb); \
         } \
         (owp)[words - 1] &= VL_MASK_E(obits); \
     }
@@ -492,13 +499,23 @@ static inline void VL_ASSIGNBIT_WO(int bit, WDataOutP owp) VL_MT_SAFE {
     { (svar).write(rd); }
 #define VL_ASSIGN_SBQ(obits, svar, rd) \
     { (svar).write(rd); }
+#define VL_SC_BITS_PER_DIGIT 30  // This comes from sc_nbdefs.h BITS_PER_DIGIT
 #define VL_ASSIGN_SBW(obits, svar, rwp) \
     { \
         sc_biguint<(obits)> _butemp; \
-        for (int i = 0; i < VL_WORDS_I(obits); ++i) { \
-            int msb = ((i + 1) * VL_IDATASIZE) - 1; \
-            msb = (msb >= (obits)) ? ((obits)-1) : msb; \
-            _butemp.range(msb, i* VL_IDATASIZE) = (rwp)[i]; \
+        int32_t lsb = 0; \
+        uint32_t* chunk = _butemp.get_raw(); \
+        while (lsb + VL_SC_BITS_PER_DIGIT < (obits)) { \
+            static_assert(std::is_same<IData, EData>::value, "IData and EData missmatch"); \
+            const uint32_t data = VL_SEL_IWII(lsb + VL_SC_BITS_PER_DIGIT + 1, (rwp).data(), lsb, \
+                                              VL_SC_BITS_PER_DIGIT); \
+            *chunk = data & VL_MASK_E(VL_SC_BITS_PER_DIGIT); \
+            ++chunk; \
+            lsb += VL_SC_BITS_PER_DIGIT; \
+        } \
+        if (lsb < (obits)) { \
+            const uint32_t msb_data = VL_SEL_IWII((obits) + 1, (rwp).data(), lsb, (obits)-lsb); \
+            *chunk = msb_data & VL_MASK_E((obits)-lsb); \
         } \
         (svar).write(_butemp); \
     }
diff --git a/src/V3Ast.cpp b/src/V3Ast.cpp
index 2f1467f03..7694e1e69 100644
--- a/src/V3Ast.cpp
+++ b/src/V3Ast.cpp
@@ -165,22 +165,22 @@ string AstNode::prettyName(const string& namein) {
             continue;
         }
         if (pos[0] == '_' && pos[1] == '_') {  // Short-circuit
-            if (0 == strncmp(pos, "__BRA__", 7)) {
+            if (0 == std::strncmp(pos, "__BRA__", 7)) {
                 pretty += "[";
                 pos += 7;
                 continue;
             }
-            if (0 == strncmp(pos, "__KET__", 7)) {
+            if (0 == std::strncmp(pos, "__KET__", 7)) {
                 pretty += "]";
                 pos += 7;
                 continue;
             }
-            if (0 == strncmp(pos, "__DOT__", 7)) {
+            if (0 == std::strncmp(pos, "__DOT__", 7)) {
                 pretty += ".";
                 pos += 7;
                 continue;
             }
-            if (0 == strncmp(pos, "__PVT__", 7)) {
+            if (0 == std::strncmp(pos, "__PVT__", 7)) {
                 pretty += "";
                 pos += 7;
                 continue;
diff --git a/src/V3Ast.h b/src/V3Ast.h
index 4be593993..11f320f70 100644
--- a/src/V3Ast.h
+++ b/src/V3Ast.h
@@ -517,8 +517,9 @@ public:
         return names[m_e];
     }
     static void selfTest() {
-        UASSERT(0 == strcmp(VBasicDTypeKwd(_ENUM_MAX).ascii(), " MAX"), "SelfTest: Enum mismatch");
-        UASSERT(0 == strcmp(VBasicDTypeKwd(_ENUM_MAX).dpiType(), " MAX"),
+        UASSERT(0 == std::strcmp(VBasicDTypeKwd(_ENUM_MAX).ascii(), " MAX"),
+                "SelfTest: Enum mismatch");
+        UASSERT(0 == std::strcmp(VBasicDTypeKwd(_ENUM_MAX).dpiType(), " MAX"),
                 "SelfTest: Enum mismatch");
     }
     inline VBasicDTypeKwd()
@@ -786,6 +787,10 @@ public:
         return (m_e == WIRE || m_e == WREAL || m_e == IMPLICITWIRE || m_e == TRIWIRE || m_e == TRI0
                 || m_e == TRI1 || m_e == PORT || m_e == SUPPLY0 || m_e == SUPPLY1 || m_e == VAR);
     }
+    bool isNet() const {
+        return (m_e == WIRE || m_e == IMPLICITWIRE || m_e == TRIWIRE || m_e == TRI0 || m_e == TRI1
+                || m_e == SUPPLY0 || m_e == SUPPLY1);
+    }
     bool isContAssignable() const {  // In Verilog, always ok in SystemVerilog
         return (m_e == SUPPLY0 || m_e == SUPPLY1 || m_e == WIRE || m_e == WREAL
                 || m_e == IMPLICITWIRE || m_e == TRIWIRE || m_e == TRI0 || m_e == TRI1
@@ -1029,6 +1034,32 @@ inline std::ostream& operator<<(std::ostream& os, const VParseRefExp& rhs) {
     return os << rhs.ascii();
 }
 
+//######################################################################
+
+class VStrength final {
+public:
+    enum en : uint8_t { HIGHZ, SMALL, MEDIUM, WEAK, LARGE, PULL, STRONG, SUPPLY };
+    enum en m_e;
+
+    inline VStrength(en strengthLevel)
+        : m_e(strengthLevel) {}
+    explicit inline VStrength(int _e)
+        : m_e(static_cast<en>(_e)) {}  // Need () or GCC 4.8 false warning
+
+    operator en() const { return m_e; }
+    const char* ascii() const {
+        static const char* const names[]
+            = {"highz", "small", "medium", "weak", "large", "pull", "strong", "supply"};
+        return names[m_e];
+    }
+};
+inline bool operator==(const VStrength& lhs, const VStrength& rhs) { return lhs.m_e == rhs.m_e; }
+inline bool operator==(const VStrength& lhs, VStrength::en rhs) { return lhs.m_e == rhs; }
+inline bool operator==(VStrength::en lhs, const VStrength& rhs) { return lhs == rhs.m_e; }
+inline std::ostream& operator<<(std::ostream& os, const VStrength& rhs) {
+    return os << rhs.ascii();
+}
+
 //######################################################################
 // VNumRange - Structure containing numeric range information
 // See also AstRange, which is a symbolic version of this
diff --git a/src/V3AstNodes.cpp b/src/V3AstNodes.cpp
index 59c3d4982..2d6b2e4da 100644
--- a/src/V3AstNodes.cpp
+++ b/src/V3AstNodes.cpp
@@ -1834,6 +1834,10 @@ void AstSenItem::dump(std::ostream& str) const {
     this->AstNode::dump(str);
     str << " [" << edgeType().ascii() << "]";
 }
+void AstStrengthSpec::dump(std::ostream& str) const {
+    this->AstNode::dump(str);
+    str << " (" << m_s0.ascii() << ", " << m_s1.ascii() << ")";
+}
 void AstParseRef::dump(std::ostream& str) const {
     this->AstNode::dump(str);
     str << " [" << expect().ascii() << "]";
diff --git a/src/V3AstNodes.h b/src/V3AstNodes.h
index d2bfd630f..1cb1ac17e 100644
--- a/src/V3AstNodes.h
+++ b/src/V3AstNodes.h
@@ -290,6 +290,23 @@ public:
     virtual bool same(const AstNode* /*samep*/) const override { return true; }
 };
 
+class AstStrengthSpec final : public AstNode {
+private:
+    VStrength m_s0;  // Drive 0 strength
+    VStrength m_s1;  // Drive 1 strength
+
+public:
+    AstStrengthSpec(FileLine* fl, VStrength s0, VStrength s1)
+        : ASTGEN_SUPER_StrengthSpec(fl)
+        , m_s0{s0}
+        , m_s1{s1} {}
+
+    ASTNODE_NODE_FUNCS(StrengthSpec)
+    VStrength strength0() { return m_s0; }
+    VStrength strength1() { return m_s1; }
+    virtual void dump(std::ostream& str) const override;
+};
+
 class AstGatePin final : public AstNodeMath {
     // Possibly expand a gate primitive input pin value to match the range of the gate primitive
 public:
@@ -2098,6 +2115,7 @@ private:
     bool m_isRand : 1;  // Random variable
     bool m_isConst : 1;  // Table contains constant data
     bool m_isContinuously : 1;  // Ever assigned continuously (for force/release)
+    bool m_hasStrengthAssignment : 1;  // Is on LHS of assignment with strength specifier
     bool m_isStatic : 1;  // Static C variable (for Verilog see instead isAutomatic)
     bool m_isPulldown : 1;  // Tri0
     bool m_isPullup : 1;  // Tri1
@@ -2139,6 +2157,7 @@ private:
         m_isRand = false;
         m_isConst = false;
         m_isContinuously = false;
+        m_hasStrengthAssignment = false;
         m_isStatic = false;
         m_isPulldown = false;
         m_isPullup = false;
@@ -2303,6 +2322,8 @@ public:
     void isIfaceParent(bool flag) { m_isIfaceParent = flag; }
     void funcLocal(bool flag) { m_funcLocal = flag; }
     void funcReturn(bool flag) { m_funcReturn = flag; }
+    void hasStrengthAssignment(bool flag) { m_hasStrengthAssignment = flag; }
+    bool hasStrengthAssignment() { return m_hasStrengthAssignment; }
     void isDpiOpenArray(bool flag) { m_isDpiOpenArray = flag; }
     bool isDpiOpenArray() const { return m_isDpiOpenArray; }
     bool isHideLocal() const { return m_isHideLocal; }
@@ -2340,6 +2361,7 @@ public:
     bool isIfaceRef() const { return (varType() == VVarType::IFACEREF); }
     bool isIfaceParent() const { return m_isIfaceParent; }
     bool isSignal() const { return varType().isSignal(); }
+    bool isNet() const { return varType().isNet(); }
     bool isTemp() const { return varType().isTemp(); }
     bool isToggleCoverable() const {
         return ((isIO() || isSignal())
@@ -3648,6 +3670,8 @@ public:
     AstAssignW(FileLine* fl, AstNode* lhsp, AstNode* rhsp, AstNode* timingControlp = nullptr)
         : ASTGEN_SUPER_AssignW(fl, lhsp, rhsp, timingControlp) {}
     ASTNODE_NODE_FUNCS(AssignW)
+    AstStrengthSpec* strengthSpecp() const { return VN_AS(op4p(), StrengthSpec); }
+    void strengthSpecp(AstStrengthSpec* const strengthSpecp) { setOp4p((AstNode*)strengthSpecp); }
     virtual AstNode* cloneType(AstNode* lhsp, AstNode* rhsp) override {
         AstNode* const controlp = timingControlp() ? timingControlp()->cloneTree(false) : nullptr;
         return new AstAssignW(this->fileline(), lhsp, rhsp, controlp);
diff --git a/src/V3Begin.cpp b/src/V3Begin.cpp
index d2e9e66d7..4bdc05cb4 100644
--- a/src/V3Begin.cpp
+++ b/src/V3Begin.cpp
@@ -86,7 +86,7 @@ private:
             string::size_type pos;
             while ((pos = dottedname.find("__DOT__")) != string::npos) {
                 const string ident = dottedname.substr(0, pos);
-                dottedname = dottedname.substr(pos + strlen("__DOT__"));
+                dottedname = dottedname.substr(pos + std::strlen("__DOT__"));
                 if (nodep->name() != "") {
                     m_displayScope = dot(m_displayScope, ident);
                     m_namedScope = dot(m_namedScope, ident);
diff --git a/src/V3Const.cpp b/src/V3Const.cpp
index c962996be..9b6cfe84c 100644
--- a/src/V3Const.cpp
+++ b/src/V3Const.cpp
@@ -2872,6 +2872,7 @@ private:
         if (m_wremove && !m_params && m_doNConst && m_modp && operandConst(nodep->rhsp())
             && !VN_AS(nodep->rhsp(), Const)->num().isFourState()
             && varrefp  // Don't do messes with BITREFs/ARRAYREFs
+            && !varrefp->varp()->hasStrengthAssignment()  // Strengths are resolved in V3Tristate
             && !varrefp->varp()->valuep()  // Not already constified
             && !varrefp->varScopep()) {  // Not scoped (or each scope may have different initial
                                          // value)
diff --git a/src/V3EmitCBase.cpp b/src/V3EmitCBase.cpp
index 1e3e9383f..40198fa76 100644
--- a/src/V3EmitCBase.cpp
+++ b/src/V3EmitCBase.cpp
@@ -57,11 +57,11 @@ string EmitCBaseVisitor::funcNameProtect(const AstCFunc* nodep, const AstNodeMod
     return name;
 }
 
-AstCFile* EmitCBaseVisitor::newCFile(const string& filename, bool slow, bool source) {
+AstCFile* EmitCBaseVisitor::newCFile(const string& filename, bool slow, bool source, bool add) {
     AstCFile* const cfilep = new AstCFile(v3Global.rootp()->fileline(), filename);
     cfilep->slow(slow);
     cfilep->source(source);
-    v3Global.rootp()->addFilesp(cfilep);
+    if (add) v3Global.rootp()->addFilesp(cfilep);
     return cfilep;
 }
 
diff --git a/src/V3EmitCBase.h b/src/V3EmitCBase.h
index 66b954f35..2451cfdfc 100644
--- a/src/V3EmitCBase.h
+++ b/src/V3EmitCBase.h
@@ -100,7 +100,7 @@ public:
                && (varp->basicp() && !varp->basicp()->isOpaque());  // Aggregates can't be anon
     }
 
-    static AstCFile* newCFile(const string& filename, bool slow, bool source);
+    static AstCFile* newCFile(const string& filename, bool slow, bool source, bool add = true);
     string cFuncArgs(const AstCFunc* nodep);
     void emitCFuncHeader(const AstCFunc* funcp, const AstNodeModule* modp, bool withScope);
     void emitCFuncDecl(const AstCFunc* funcp, const AstNodeModule* modp, bool cLinkage = false);
diff --git a/src/V3EmitCFunc.h b/src/V3EmitCFunc.h
index 43d016c3f..1426679a7 100644
--- a/src/V3EmitCFunc.h
+++ b/src/V3EmitCFunc.h
@@ -36,18 +36,20 @@ constexpr int EMITC_NUM_CONSTW = 8;
 
 class EmitCLazyDecls final : public VNVisitor {
     // NODE STATE/TYPES
-    //  AstNode::user2() -> bool. Already emitted decl for symbols.
-    const VNUser2InUse m_inuser2;
+    // None allowed to support threaded emitting
 
     // MEMBERS
     std::unordered_set<string> m_emittedManually;  // Set of names already declared manually.
     EmitCBaseVisitor& m_emitter;  // For access to file output
     bool m_needsBlankLine = false;  // Emit blank line if any declarations were emitted (cosmetic)
+    std::set<AstNode*> m_emitted;  // -> in set. Already emitted decl for symbols.
 
     // METHODS
+    bool declaredOnce(AstNode* nodep) { return m_emitted.insert(nodep).second; }
+
     void lazyDeclare(AstCFunc* funcp) {
         // Already declared in this compilation unit
-        if (funcp->user2SetOnce()) return;
+        if (!declaredOnce(funcp)) return;
         // Check if this kind of function is lazily declared
         if (!(funcp->isMethod() && funcp->isLoose()) && !funcp->dpiImportPrototype()) return;
         // Already declared manually
@@ -58,7 +60,7 @@ class EmitCLazyDecls final : public VNVisitor {
     }
 
     void lazyDeclareConstPoolVar(AstVar* varp) {
-        if (varp->user2SetOnce()) return;  // Already declared
+        if (!declaredOnce(varp)) return;  // Already declared
         const string nameProtect
             = m_emitter.topClassName() + "__ConstPool__" + varp->nameProtect();
         m_emitter.puts("extern const ");
@@ -106,8 +108,8 @@ public:
         m_emitter.puts(suffix);
         m_emitter.ensureNewLine();
     }
-    void declared(AstCFunc* nodep) { nodep->user2SetOnce(); }
-    void reset() { AstNode::user2ClearTree(); }
+    void declared(AstCFunc* nodep) { m_emitted.insert(nodep); }
+    void reset() { m_emitted.clear(); }
 };
 
 //######################################################################
diff --git a/src/V3EmitCImp.cpp b/src/V3EmitCImp.cpp
index ee053cd4b..f4c90a5ed 100644
--- a/src/V3EmitCImp.cpp
+++ b/src/V3EmitCImp.cpp
@@ -148,6 +148,7 @@ class EmitCImp final : EmitCFunc {
     const std::set<string>* m_requiredHeadersp;  // Header files required by output file
     std::string m_subFileName;  // substring added to output filenames
     V3UniqueNames m_uniqueNames;  // For generating unique file names
+    std::deque<AstCFile*>& m_cfilesr;  // cfiles generated by this emit
 
     // METHODS
     void openNextOutputFile(const std::set<string>& headers, const string& subFileName) {
@@ -160,7 +161,8 @@ class EmitCImp final : EmitCFunc {
             // Unfortunately we have some lint checks here, so we can't just skip processing.
             // We should move them to a different stage.
             const string filename = VL_DEV_NULL;
-            newCFile(filename, /* slow: */ m_slow, /* source: */ true);
+            m_cfilesr.push_back(
+                newCFile(filename, /* slow: */ m_slow, /* source: */ true, /* add */ false));
             m_ofp = new V3OutCFile(filename);
         } else {
             string filename = v3Global.opt.makeDir() + "/" + prefixNameProtect(m_fileModp);
@@ -170,7 +172,8 @@ class EmitCImp final : EmitCFunc {
             }
             if (m_slow) filename += "__Slow";
             filename += ".cpp";
-            newCFile(filename, /* slow: */ m_slow, /* source: */ true);
+            m_cfilesr.push_back(
+                newCFile(filename, /* slow: */ m_slow, /* source: */ true, /* add */ false));
             m_ofp = v3Global.opt.systemC() ? new V3OutScFile(filename) : new V3OutCFile(filename);
         }
 
@@ -527,9 +530,10 @@ class EmitCImp final : EmitCFunc {
         EmitCFunc::visit(nodep);
     }
 
-    explicit EmitCImp(const AstNodeModule* modp, bool slow)
+    explicit EmitCImp(const AstNodeModule* modp, bool slow, std::deque<AstCFile*>& cfilesr)
         : m_fileModp{modp}
-        , m_slow{slow} {
+        , m_slow{slow}
+        , m_cfilesr{cfilesr} {
         UINFO(5, "  Emitting implementation of " << prefixNameProtect(modp) << endl);
 
         m_modp = modp;
@@ -548,7 +552,9 @@ class EmitCImp final : EmitCFunc {
     virtual ~EmitCImp() override = default;
 
 public:
-    static void main(const AstNodeModule* modp, bool slow) { EmitCImp{modp, slow}; }
+    static void main(const AstNodeModule* modp, bool slow, std::deque<AstCFile*>& cfilesr) {
+        EmitCImp{modp, slow, cfilesr};
+    }
 };
 
 //######################################################################
@@ -556,14 +562,14 @@ public:
 
 class EmitCTrace final : EmitCFunc {
     // NODE STATE/TYPES
-    // Cleared on netlist
-    //  AstNode::user1() -> int.  Enum number
-    const VNUser1InUse m_inuser1;
+    // None allowed to support threaded emitting
 
     // MEMBERS
     const bool m_slow;  // Making slow file
     int m_enumNum = 0;  // Enumeration number (whole netlist)
     V3UniqueNames m_uniqueNames;  // For generating unique file names
+    std::unordered_map<AstNode*, int> m_enumNumMap;  // EnumDType to enumeration number
+    std::deque<AstCFile*>& m_cfilesr;  // cfiles generated by this emit
 
     // METHODS
     void openNextOutputFile() {
@@ -578,8 +584,9 @@ class EmitCTrace final : EmitCFunc {
         if (m_slow) filename += "__Slow";
         filename += ".cpp";
 
-        AstCFile* const cfilep = newCFile(filename, m_slow, true /*source*/);
+        AstCFile* const cfilep = newCFile(filename, m_slow, true /*source*/, false /*add*/);
         cfilep->support(true);
+        m_cfilesr.push_back(cfilep);
 
         if (optSystemC()) {
             m_ofp = new V3OutScFile(filename);
@@ -715,10 +722,10 @@ class EmitCTrace final : EmitCFunc {
             // Skip over refs-to-refs, but stop before final ref so can get data type name
             // Alternatively back in V3Width we could push enum names from upper typedefs
             if (AstEnumDType* const enump = VN_CAST(nodep->skipRefToEnump(), EnumDType)) {
-                int enumNum = enump->user1();
+                int enumNum = m_enumNumMap[enump];
                 if (!enumNum) {
                     enumNum = ++m_enumNum;
-                    enump->user1(enumNum);
+                    m_enumNumMap[enump] = enumNum;
                     int nvals = 0;
                     puts("{\n");
                     puts("const char* " + protect("__VenumItemNames") + "[]\n");
@@ -868,8 +875,9 @@ class EmitCTrace final : EmitCFunc {
         }
     }
 
-    explicit EmitCTrace(AstNodeModule* modp, bool slow)
-        : m_slow{slow} {
+    explicit EmitCTrace(AstNodeModule* modp, bool slow, std::deque<AstCFile*>& cfilesr)
+        : m_slow{slow}
+        , m_cfilesr{cfilesr} {
         m_modp = modp;
         // Open output file
         openNextOutputFile();
@@ -883,7 +891,9 @@ class EmitCTrace final : EmitCFunc {
     virtual ~EmitCTrace() override = default;
 
 public:
-    static void main(AstNodeModule* modp, bool slow) { EmitCTrace{modp, slow}; }
+    static void main(AstNodeModule* modp, bool slow, std::deque<AstCFile*>& cfilesr) {
+        EmitCTrace{modp, slow, cfilesr};
+    }
 };
 
 //######################################################################
@@ -893,19 +903,27 @@ void V3EmitC::emitcImp() {
     UINFO(2, __FUNCTION__ << ": " << endl);
     // Make parent module pointers available.
     const EmitCParentModule emitCParentModule;
+    std::list<std::deque<AstCFile*>> cfiles;
 
     // Process each module in turn
     for (const AstNode* nodep = v3Global.rootp()->modulesp(); nodep; nodep = nodep->nextp()) {
         if (VN_IS(nodep, Class)) continue;  // Imped with ClassPackage
         const AstNodeModule* const modp = VN_AS(nodep, NodeModule);
-        EmitCImp::main(modp, /* slow: */ true);
-        EmitCImp::main(modp, /* slow: */ false);
+        cfiles.emplace_back();
+        EmitCImp::main(modp, /* slow: */ true, cfiles.back());
+        cfiles.emplace_back();
+        EmitCImp::main(modp, /* slow: */ false, cfiles.back());
     }
 
     // Emit trace routines (currently they can only exist in the top module)
     if (v3Global.opt.trace() && !v3Global.opt.lintOnly()) {
-        EmitCTrace::main(v3Global.rootp()->topModulep(), /* slow: */ true);
-        EmitCTrace::main(v3Global.rootp()->topModulep(), /* slow: */ false);
+        cfiles.emplace_back();
+        EmitCTrace::main(v3Global.rootp()->topModulep(), /* slow: */ true, cfiles.back());
+        cfiles.emplace_back();
+        EmitCTrace::main(v3Global.rootp()->topModulep(), /* slow: */ false, cfiles.back());
+    }
+    for (const auto& collr : cfiles) {
+        for (const auto cfilep : collr) v3Global.rootp()->addFilesp(cfilep);
     }
 }
 
diff --git a/src/V3EmitCModel.cpp b/src/V3EmitCModel.cpp
index 443e4f3f8..74104e500 100644
--- a/src/V3EmitCModel.cpp
+++ b/src/V3EmitCModel.cpp
@@ -555,7 +555,7 @@ class EmitCModel final : public EmitCFunc {
                 // Some hackery to locate handle__V for trace_init_task
                 // Considered a pragma on the handle, but that still doesn't help us attach it here
                 string handle = funcp->name();
-                const size_t wr_len = strlen("__Vdpiimwrap_");
+                const size_t wr_len = std::strlen("__Vdpiimwrap_");
                 UASSERT_OBJ(handle.substr(0, wr_len) == "__Vdpiimwrap_", funcp,
                             "Strange trace_init_task function name");
                 handle = "vlSymsp->TOP." + handle.substr(wr_len);
diff --git a/src/V3EmitCSyms.cpp b/src/V3EmitCSyms.cpp
index 8195d705d..d2c3fbf93 100644
--- a/src/V3EmitCSyms.cpp
+++ b/src/V3EmitCSyms.cpp
@@ -211,7 +211,7 @@ class EmitCSyms final : EmitCBaseVisitor {
                     const string::size_type dpos = whole.rfind("__DOT__");
                     if (dpos != string::npos) {
                         scpName = whole.substr(0, dpos);
-                        varBase = whole.substr(dpos + strlen("__DOT__"));
+                        varBase = whole.substr(dpos + std::strlen("__DOT__"));
                     } else {
                         varBase = whole;
                     }
diff --git a/src/V3File.cpp b/src/V3File.cpp
index 57452b969..c4adf58bc 100644
--- a/src/V3File.cpp
+++ b/src/V3File.cpp
@@ -94,7 +94,7 @@ class V3FileDependImp final {
                 const string fn = filename();
                 const int err = stat(fn.c_str(), &m_stat);
                 if (err != 0) {
-                    memset(&m_stat, 0, sizeof(m_stat));
+                    std::memset(&m_stat, 0, sizeof(m_stat));
                     m_stat.st_mtime = 1;
                     m_exists = false;
                     // Not an error... This can occur due to `line directives in the .vpp files
@@ -389,7 +389,7 @@ private:
         if (!m_pidExited && waitpid(m_pid, &m_pidStatus, hang ? 0 : WNOHANG)) {
             UINFO(1, "--pipe-filter: Exited, status "
                          << m_pidStatus << " exit=" << WEXITSTATUS(m_pidStatus) << " err"
-                         << strerror(errno) << endl);
+                         << std::strerror(errno) << endl);
             m_readEof = true;
             m_pidExited = true;
         }
@@ -495,7 +495,7 @@ private:
         constexpr int P_WR = 1;
 
         if (pipe(fd_stdin) != 0 || pipe(fd_stdout) != 0) {
-            v3fatal("--pipe-filter: Can't pipe: " << strerror(errno));
+            v3fatal("--pipe-filter: Can't pipe: " << std::strerror(errno));
         }
         if (fd_stdin[P_RD] <= 2 || fd_stdin[P_WR] <= 2 || fd_stdout[P_RD] <= 2
             || fd_stdout[P_WR] <= 2) {
@@ -507,7 +507,7 @@ private:
         UINFO(1, "--pipe-filter: /bin/sh -c " << command << endl);
 
         const pid_t pid = fork();
-        if (pid < 0) v3fatal("--pipe-filter: fork failed: " << strerror(errno));
+        if (pid < 0) v3fatal("--pipe-filter: fork failed: " << std::strerror(errno));
         if (pid == 0) {  // Child
             UINFO(6, "In child\n");
             close(fd_stdin[P_WR]);
@@ -518,7 +518,7 @@ private:
 
             execl("/bin/sh", "sh", "-c", command.c_str(), static_cast<char*>(nullptr));
             // Don't use v3fatal, we don't share the common structures any more
-            fprintf(stderr, "--pipe-filter: exec failed: %s\n", strerror(errno));
+            fprintf(stderr, "--pipe-filter: exec failed: %s\n", std::strerror(errno));
             _exit(1);
         } else {  // Parent
             UINFO(6, "In parent, child pid " << pid << " stdin " << fd_stdin[P_WR] << "->"
diff --git a/src/V3File.h b/src/V3File.h
index 309f136c9..95b29eb8d 100644
--- a/src/V3File.h
+++ b/src/V3File.h
@@ -224,7 +224,7 @@ private:
         std::size_t len = strlen(str);
         std::size_t availableBytes = WRITE_BUFFER_SIZE_BYTES - m_usedBytes;
         while (VL_UNLIKELY(len >= availableBytes)) {
-            memcpy(m_bufferp->data() + m_usedBytes, str, availableBytes);
+            std::memcpy(m_bufferp->data() + m_usedBytes, str, availableBytes);
             m_usedBytes = WRITE_BUFFER_SIZE_BYTES;
             writeBlock();
             str += availableBytes;
@@ -232,7 +232,7 @@ private:
             availableBytes = WRITE_BUFFER_SIZE_BYTES;
         }
         if (len > 0) {
-            memcpy(m_bufferp->data() + m_usedBytes, str, len);
+            std::memcpy(m_bufferp->data() + m_usedBytes, str, len);
             m_usedBytes += len;
         }
     }
diff --git a/src/V3FileLine.cpp b/src/V3FileLine.cpp
index e5b2e32ae..fd7669275 100644
--- a/src/V3FileLine.cpp
+++ b/src/V3FileLine.cpp
@@ -185,7 +185,7 @@ void FileLine::lineDirective(const char* textp, int& enterExitRef) {
     const char* const ln = textp;
     while (*textp && !isspace(*textp)) textp++;
     if (isdigit(*ln)) {
-        lineno(atoi(ln));
+        lineno(std::atoi(ln));
     } else {
         fail = true;
     }
@@ -207,7 +207,7 @@ void FileLine::lineDirective(const char* textp, int& enterExitRef) {
     // Grab level
     while (*textp && (isspace(*textp) || *textp == '"')) textp++;
     if (isdigit(*textp)) {
-        enterExitRef = atoi(textp);
+        enterExitRef = std::atoi(textp);
         if (enterExitRef >= 3) fail = true;
     } else {
         enterExitRef = 0;
diff --git a/src/V3LinkDot.cpp b/src/V3LinkDot.cpp
index 02e6b439b..493beaf4d 100644
--- a/src/V3LinkDot.cpp
+++ b/src/V3LinkDot.cpp
@@ -919,7 +919,7 @@ class LinkDotFindVisitor final : public VNVisitor {
         string::size_type pos;
         if ((pos = dottedname.rfind("__DOT__")) != string::npos) {
             const string dotted = dottedname.substr(0, pos);
-            const string ident = dottedname.substr(pos + strlen("__DOT__"));
+            const string ident = dottedname.substr(pos + std::strlen("__DOT__"));
             string baddot;
             VSymEnt* okSymp;
             aboveSymp = m_statep->findDotted(nodep->fileline(), aboveSymp, dotted, baddot, okSymp);
diff --git a/src/V3LinkLValue.cpp b/src/V3LinkLValue.cpp
index 9ef0c248d..09c91ff1b 100644
--- a/src/V3LinkLValue.cpp
+++ b/src/V3LinkLValue.cpp
@@ -37,6 +37,7 @@ private:
 
     // STATE
     bool m_setContinuously = false;  // Set that var has some continuous assignment
+    bool m_setStrengthSpecified = false;  // Set that var has assignment with strength specified.
     VAccess m_setRefLvalue;  // Set VarRefs to lvalues for pin assignments
     AstNodeFTask* m_ftaskp = nullptr;  // Function or task we're inside
 
@@ -51,6 +52,9 @@ private:
         if (nodep->varp()) {
             if (nodep->access().isWriteOrRW() && m_setContinuously) {
                 nodep->varp()->isContinuously(true);
+                // Strength may only be specified in continuous assignment,
+                // so it is needed to check only if m_setContinuously is true
+                if (m_setStrengthSpecified) nodep->varp()->hasStrengthAssignment(true);
             }
             if (nodep->access().isWriteOrRW() && !m_ftaskp && nodep->varp()->isReadOnly()) {
                 nodep->v3warn(ASSIGNIN,
@@ -78,9 +82,13 @@ private:
         {
             m_setRefLvalue = VAccess::WRITE;
             m_setContinuously = VN_IS(nodep, AssignW) || VN_IS(nodep, AssignAlias);
+            if (AstAssignW* assignwp = VN_CAST(nodep, AssignW)) {
+                if (assignwp->strengthSpecp()) m_setStrengthSpecified = true;
+            }
             iterateAndNextNull(nodep->lhsp());
             m_setRefLvalue = VAccess::NOCHANGE;
             m_setContinuously = false;
+            m_setStrengthSpecified = false;
             iterateAndNextNull(nodep->rhsp());
         }
     }
diff --git a/src/V3Number.cpp b/src/V3Number.cpp
index d7473cd29..81b059442 100644
--- a/src/V3Number.cpp
+++ b/src/V3Number.cpp
@@ -156,14 +156,15 @@ void V3Number::V3NumberCreate(AstNode* nodep, const char* sourcep, FileLine* fl)
         }
         value_startp = cp;
 
-        if (atoi(widthn.c_str())) {
-            if (atoi(widthn.c_str()) < 0 || atoi(widthn.c_str()) > v3Global.opt.maxNumWidth()) {
+        if (std::atoi(widthn.c_str())) {
+            if (std::atoi(widthn.c_str()) < 0
+                || std::atoi(widthn.c_str()) > v3Global.opt.maxNumWidth()) {
                 // atoi might convert large number to negative, so can't tell which
                 v3error("Unsupported: Width of number exceeds implementation limit: "
                         << sourcep << "  (IEEE 1800-2017 6.9.1)");
                 width(v3Global.opt.maxNumWidth(), true);
             } else {
-                width(atoi(widthn.c_str()), true);
+                width(std::atoi(widthn.c_str()), true);
             }
         }
     } else {
@@ -278,7 +279,8 @@ void V3Number::V3NumberCreate(AstNode* nodep, const char* sourcep, FileLine* fl)
         }
     } else {
         // Convert bin/octal number to hex
-        for (const char* cp = value_startp + strlen(value_startp) - 1; cp >= value_startp; cp--) {
+        for (const char* cp = value_startp + std::strlen(value_startp) - 1; cp >= value_startp;
+             cp--) {
             if (*cp != '_' && *cp != '0' && obit >= width()) {
                 v3error("Too many digits for " << width() << " bit number: " << sourcep);
                 break;
@@ -698,7 +700,7 @@ string V3Number::displayed(FileLine* fl, const string& vformat) const {
                 if (fmtsize != "0") str += ' ';
             }
         }
-        const size_t fmtsizen = static_cast<size_t>(atoi(fmtsize.c_str()));
+        const size_t fmtsizen = static_cast<size_t>(std::atoi(fmtsize.c_str()));
         str = displayPad(fmtsizen, ' ', left, str);
         return str;
     }
@@ -747,7 +749,7 @@ string V3Number::displayed(FileLine* fl, const string& vformat) const {
         }
         const bool zeropad = fmtsize.length() > 0 && fmtsize[0] == '0';
         // fmtsize might have changed since we parsed the %fmtsize
-        const size_t fmtsizen = static_cast<size_t>(atoi(fmtsize.c_str()));
+        const size_t fmtsizen = static_cast<size_t>(std::atoi(fmtsize.c_str()));
         str = displayPad(fmtsizen, (zeropad ? '0' : ' '), left, str);
         return str;
     }
@@ -802,7 +804,7 @@ string V3Number::displayed(FileLine* fl, const string& vformat) const {
         return str;
     }
     case '@': {  // Packed string
-        const size_t fmtsizen = static_cast<size_t>(atoi(fmtsize.c_str()));
+        const size_t fmtsizen = static_cast<size_t>(std::atoi(fmtsize.c_str()));
         str = displayPad(fmtsizen, ' ', left, toString());
         return str;
     }
diff --git a/src/V3OptionParser.cpp b/src/V3OptionParser.cpp
index 308a26e10..8035916e7 100644
--- a/src/V3OptionParser.cpp
+++ b/src/V3OptionParser.cpp
@@ -130,8 +130,8 @@ V3OptionParser::ActionIfs* V3OptionParser::find(const char* optp) {
     for (auto&& act : m_pimpl->m_options) {
         if (act.second->isFOnOffAllowed()) {  // Find starts with "-fno"
             if (const char* const nop
-                = VString::startsWith(optp, "-fno-") ? (optp + strlen("-fno-")) : nullptr) {
-                if (act.first.substr(strlen("-f"), std::string::npos)
+                = VString::startsWith(optp, "-fno-") ? (optp + std::strlen("-fno-")) : nullptr) {
+                if (act.first.substr(std::strlen("-f"), std::string::npos)
                     == nop) {  // [-f]opt = [-fno-]opt
                     return act.second.get();
                 }
@@ -139,7 +139,7 @@ V3OptionParser::ActionIfs* V3OptionParser::find(const char* optp) {
         }
         if (act.second->isOnOffAllowed()) {  // Find starts with "-no"
             if (const char* const nop
-                = VString::startsWith(optp, "-no") ? (optp + strlen("-no")) : nullptr) {
+                = VString::startsWith(optp, "-no") ? (optp + std::strlen("-no")) : nullptr) {
                 if (act.first == nop || act.first == (std::string{"-"} + nop)) {
                     return act.second.get();
                 }
@@ -206,7 +206,7 @@ void V3OptionParser::finalize() {
         m_pimpl->m_spellCheck.pushCandidate(opt.first);
         if (opt.second->isFOnOffAllowed()) {
             m_pimpl->m_spellCheck.pushCandidate(
-                "-fno-" + opt.first.substr(strlen("-f"), std::string::npos));
+                "-fno-" + opt.first.substr(std::strlen("-f"), std::string::npos));
         }
         if (opt.second->isOnOffAllowed()) m_pimpl->m_spellCheck.pushCandidate("-no" + opt.first);
     }
diff --git a/src/V3Options.cpp b/src/V3Options.cpp
index 1f50989cc..5e0a4a57f 100644
--- a/src/V3Options.cpp
+++ b/src/V3Options.cpp
@@ -435,6 +435,11 @@ string V3Options::allArgsStringForHierBlock(bool forTop) const {
     return out;
 }
 
+void V3Options::ccSet() {  // --cc
+    m_outFormatOk = true;
+    m_systemC = false;
+}
+
 //######################################################################
 // File searching
 
@@ -727,9 +732,10 @@ bool V3Options::coroutineSupport() {
 // V3 Options notification methods
 
 void V3Options::notify() {
-    FileLine* const cmdfl = new FileLine(FileLine::commandLineFilename());
-
     // Notify that all arguments have been passed and final modification can be made.
+    FileLine* const cmdfl = new FileLine{FileLine::commandLineFilename()};
+
+    if (!outFormatOk() && v3Global.opt.main()) ccSet();  // --main implies --cc if not provided
     if (!outFormatOk() && !cdc() && !dpiHdrOnly() && !lintOnly() && !preprocOnly() && !xmlOnly()) {
         v3fatal("verilator: Need --cc, --sc, --cdc, --dpi-hdr-only, --lint-only, "
                 "--xml-only or --E option");
@@ -910,8 +916,8 @@ void V3Options::parseOpts(FileLine* fl, int argc, char** argv) {
 //======================================================================
 
 bool V3Options::suffixed(const string& sw, const char* arg) {
-    if (strlen(arg) > sw.length()) return false;
-    return (0 == strcmp(sw.c_str() + sw.length() - strlen(arg), arg));
+    if (std::strlen(arg) > sw.length()) return false;
+    return (0 == std::strcmp(sw.c_str() + sw.length() - std::strlen(arg), arg));
 }
 
 void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char** argv) {
@@ -1010,10 +1016,7 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
     DECL_OPTION("-build", Set, &m_build);
 
     DECL_OPTION("-CFLAGS", CbVal, callStrSetter(&V3Options::addCFlags));
-    DECL_OPTION("-cc", CbCall, [this]() {
-        m_outFormatOk = true;
-        m_systemC = false;
-    });
+    DECL_OPTION("-cc", CbCall, [this]() { ccSet(); });
     DECL_OPTION("-cdc", OnOff, &m_cdc);
     DECL_OPTION("-clk", CbVal, callStrSetter(&V3Options::addClocker));
     DECL_OPTION("-no-clk", CbVal, callStrSetter(&V3Options::addNoClocker));
@@ -1024,15 +1027,15 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
     DECL_OPTION("-comp-limit-parens", Set, &m_compLimitParens).undocumented();
     DECL_OPTION("-comp-limit-syms", CbVal, [](int val) { VName::maxLength(val); }).undocumented();
     DECL_OPTION("-compiler", CbVal, [this, fl](const char* valp) {
-        if (!strcmp(valp, "clang")) {
+        if (!std::strcmp(valp, "clang")) {
             m_compLimitBlocks = 80;  // limit unknown
             m_compLimitMembers = 64;  // soft limit, has slowdown bug as of clang++ 3.8
             m_compLimitParens = 240;  // controlled by -fbracket-depth, which defaults to 256
-        } else if (!strcmp(valp, "gcc")) {
+        } else if (!std::strcmp(valp, "gcc")) {
             m_compLimitBlocks = 0;  // Bug free
             m_compLimitMembers = 64;  // soft limit, has slowdown bug as of g++ 7.1
             m_compLimitParens = 240;  // Unlimited, but generate same code as for clang
-        } else if (!strcmp(valp, "msvc")) {
+        } else if (!std::strcmp(valp, "msvc")) {
             m_compLimitBlocks = 80;  // 128, but allow some room
             m_compLimitMembers = 0;  // probably ok, and AFAIK doesn't support anon structs
             m_compLimitParens = 80;  // 128, but allow some room
@@ -1183,11 +1186,11 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
         m_makeDir = valp;
         addIncDirFallback(m_makeDir);  // Need to find generated files there too
     });
-    DECL_OPTION("-main", OnOff, &m_main).undocumented();  // Future
+    DECL_OPTION("-main", OnOff, &m_main);
     DECL_OPTION("-make", CbVal, [this, fl](const char* valp) {
-        if (!strcmp(valp, "cmake")) {
+        if (!std::strcmp(valp, "cmake")) {
             m_cmake = true;
-        } else if (!strcmp(valp, "gmake")) {
+        } else if (!std::strcmp(valp, "gmake")) {
             m_gmake = true;
         } else {
             fl->v3fatal("Unknown --make system specified: '" << valp << "'");
@@ -1280,10 +1283,7 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
     DECL_OPTION("-pins-uint8", OnOff, &m_pinsUint8);
     DECL_OPTION("-pipe-filter", Set, &m_pipeFilter);
     DECL_OPTION("-pp-comments", OnOff, &m_ppComments);
-    DECL_OPTION("-prefix", CbVal, [this](const char* valp) {
-        m_prefix = valp;
-        if (m_modPrefix == "") m_modPrefix = m_prefix;
-    });
+    DECL_OPTION("-prefix", Set, &m_prefix);
     DECL_OPTION("-private", CbCall, [this]() { m_public = false; });
     DECL_OPTION("-prof-c", OnOff, &m_profC);
     DECL_OPTION("-prof-cfuncs", CbCall, [this]() { m_profC = m_profCFuncs = true; });
@@ -1339,13 +1339,13 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
         if (m_threads < 0) fl->v3fatal("--threads must be >= 0: " << valp);
     });
     DECL_OPTION("-threads-dpi", CbVal, [this, fl](const char* valp) {
-        if (!strcmp(valp, "all")) {
+        if (!std::strcmp(valp, "all")) {
             m_threadsDpiPure = true;
             m_threadsDpiUnpure = true;
-        } else if (!strcmp(valp, "none")) {
+        } else if (!std::strcmp(valp, "none")) {
             m_threadsDpiPure = false;
             m_threadsDpiUnpure = false;
-        } else if (!strcmp(valp, "pure")) {
+        } else if (!std::strcmp(valp, "pure")) {
             m_threadsDpiPure = true;
             m_threadsDpiUnpure = false;
         } else {
@@ -1481,13 +1481,13 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
     DECL_OPTION("-waiver-output", Set, &m_waiverOutput);
 
     DECL_OPTION("-x-assign", CbVal, [this, fl](const char* valp) {
-        if (!strcmp(valp, "0")) {
+        if (!std::strcmp(valp, "0")) {
             m_xAssign = "0";
-        } else if (!strcmp(valp, "1")) {
+        } else if (!std::strcmp(valp, "1")) {
             m_xAssign = "1";
-        } else if (!strcmp(valp, "fast")) {
+        } else if (!std::strcmp(valp, "fast")) {
             m_xAssign = "fast";
-        } else if (!strcmp(valp, "unique")) {
+        } else if (!std::strcmp(valp, "unique")) {
             m_xAssign = "unique";
         } else {
             fl->v3fatal("Unknown setting for --x-assign: '"
@@ -1496,11 +1496,11 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
         }
     });
     DECL_OPTION("-x-initial", CbVal, [this, fl](const char* valp) {
-        if (!strcmp(valp, "0")) {
+        if (!std::strcmp(valp, "0")) {
             m_xInitial = "0";
-        } else if (!strcmp(valp, "fast")) {
+        } else if (!std::strcmp(valp, "fast")) {
             m_xInitial = "fast";
-        } else if (!strcmp(valp, "unique")) {
+        } else if (!std::strcmp(valp, "unique")) {
             m_xInitial = "unique";
         } else {
             fl->v3fatal("Unknown setting for --x-initial: '"
@@ -1522,11 +1522,12 @@ void V3Options::parseOptsList(FileLine* fl, const string& optdir, int argc, char
 
     for (int i = 0; i < argc;) {
         UINFO(9, " Option: " << argv[i] << endl);
-        if (!strcmp(argv[i], "-j") || !strcmp(argv[i], "--j")) {  // Allow gnu -- switches
+        if (!std::strcmp(argv[i], "-j")
+            || !std::strcmp(argv[i], "--j")) {  // Allow gnu -- switches
             ++i;
             m_buildJobs = 0;  // Unlimited parallelism
             if (i < argc && isdigit(argv[i][0])) {
-                m_buildJobs = atoi(argv[i]);
+                m_buildJobs = std::atoi(argv[i]);
                 if (m_buildJobs <= 0) {
                     fl->v3error("-j accepts positive integer, but '" << argv[i] << "' is passed");
                 }
diff --git a/src/V3Options.h b/src/V3Options.h
index 4b1b7a016..ad966e5b5 100644
--- a/src/V3Options.h
+++ b/src/V3Options.h
@@ -410,8 +410,9 @@ public:
     void addNoClocker(const string& signame);
     void addVFile(const string& filename);
     void addForceInc(const string& filename);
-    void notify();
     bool available() const { return m_available; }
+    void ccSet();
+    void notify();
 
     // ACCESSORS (options)
     bool preprocOnly() const { return m_preprocOnly; }
diff --git a/src/V3Os.cpp b/src/V3Os.cpp
index c410c6735..2abc200c0 100644
--- a/src/V3Os.cpp
+++ b/src/V3Os.cpp
@@ -347,7 +347,7 @@ int V3Os::system(const string& command) {
     const int ret = ::system(command.c_str());
     if (VL_UNCOVERABLE(ret == -1)) {
         v3fatal("Failed to execute command:"  // LCOV_EXCL_LINE
-                << command << " " << strerror(errno));
+                << command << " " << std::strerror(errno));
         return -1;  // LCOV_EXCL_LINE
     } else {
         UASSERT(WIFEXITED(ret), "system(" << command << ") returned unexpected value of " << ret);
diff --git a/src/V3ParseGrammar.cpp b/src/V3ParseGrammar.cpp
index 8e95d13c8..66670338e 100644
--- a/src/V3ParseGrammar.cpp
+++ b/src/V3ParseGrammar.cpp
@@ -84,9 +84,13 @@ AstArg* V3ParseGrammar::argWrapList(AstNode* nodep) {
 }
 
 AstNode* V3ParseGrammar::createSupplyExpr(FileLine* fileline, const string& name, int value) {
-    return new AstAssignW(
-        fileline, new AstVarRef(fileline, name, VAccess::WRITE),
-        new AstConst(fileline, AstConst::StringToParse(), (value ? "'1" : "'0")));
+    AstAssignW* assignp
+        = new AstAssignW{fileline, new AstVarRef{fileline, name, VAccess::WRITE},
+                         new AstConst{fileline, AstConst::StringToParse{}, (value ? "'1" : "'0")}};
+    AstStrengthSpec* strengthSpecp
+        = new AstStrengthSpec{fileline, VStrength::SUPPLY, VStrength::SUPPLY};
+    assignp->strengthSpecp(strengthSpecp);
+    return assignp;
 }
 
 AstRange* V3ParseGrammar::scrubRange(AstNodeRange* nrangep) {
diff --git a/src/V3ParseImp.cpp b/src/V3ParseImp.cpp
index 924a5062b..1d2832ce5 100644
--- a/src/V3ParseImp.cpp
+++ b/src/V3ParseImp.cpp
@@ -150,8 +150,8 @@ void V3ParseImp::lexVerilatorCmtLint(FileLine* fl, const char* textp, bool warnO
 
 void V3ParseImp::lexVerilatorCmtBad(FileLine* fl, const char* textp) {
     string cmtparse = textp;
-    if (cmtparse.substr(0, strlen("/*verilator")) == "/*verilator") {
-        cmtparse.replace(0, strlen("/*verilator"), "");
+    if (cmtparse.substr(0, std::strlen("/*verilator")) == "/*verilator") {
+        cmtparse.replace(0, std::strlen("/*verilator"), "");
     }
     while (isspace(cmtparse[0])) cmtparse.replace(0, 1, "");
     string cmtname;
@@ -178,14 +178,14 @@ void V3ParseImp::lexErrorPreprocDirective(FileLine* fl, const char* textp) {
 }
 
 string V3ParseImp::lexParseTag(const char* textp) {
-    string tmp = textp + strlen("/*verilator tag ");
+    string tmp = textp + std::strlen("/*verilator tag ");
     string::size_type pos;
     if ((pos = tmp.rfind("*/")) != string::npos) tmp.erase(pos);
     return tmp;
 }
 
 double V3ParseImp::lexParseTimenum(const char* textp) {
-    const size_t length = strlen(textp);
+    const size_t length = std::strlen(textp);
     char* const strgp = new char[length + 1];
     char* dp = strgp;
     const char* sp = textp;
@@ -234,7 +234,7 @@ size_t V3ParseImp::ppInputToLex(char* buf, size_t max_size) {
             m_ppBuffers.push_front(remainder);  // Put back remainder for next time
             len = (max_size - got);
         }
-        memcpy(buf + got, front.c_str(), len);
+        std::memcpy(buf + got, front.c_str(), len);
         got += len;
     }
     if (debug() >= 9) {
@@ -398,8 +398,7 @@ void V3ParseImp::tokenPipeline() {
         const int nexttok = nexttokp->token;
         yylval = curValue;
         // Now potentially munge the current token
-        if (token == '('
-            && (nexttok == ygenSTRENGTH || nexttok == ySUPPLY0 || nexttok == ySUPPLY1)) {
+        if (token == '(' && isStrengthToken(nexttok)) {
             token = yP_PAR__STRENGTH;
         } else if (token == ':') {
             if (nexttok == yBEGIN) {
@@ -483,6 +482,12 @@ void V3ParseImp::tokenPipeline() {
     // effectively returns yylval
 }
 
+bool V3ParseImp::isStrengthToken(int tok) {
+    return tok == ygenSTRENGTH || tok == ySUPPLY0 || tok == ySUPPLY1 || tok == ySTRONG0
+           || tok == ySTRONG1 || tok == yPULL0 || tok == yPULL1 || tok == yWEAK0 || tok == yWEAK1
+           || tok == yHIGHZ0 || tok == yHIGHZ1;
+}
+
 void V3ParseImp::tokenPipelineSym() {
     // If an id, change the type based on symbol table
     // Note above sometimes converts yGLOBAL to a yaID__LEX
diff --git a/src/V3ParseImp.h b/src/V3ParseImp.h
index c5cf4bd36..54a241365 100644
--- a/src/V3ParseImp.h
+++ b/src/V3ParseImp.h
@@ -121,6 +121,7 @@ struct V3ParseBisonYYSType {
         V3ErrorCode::en errcodeen;
         VAttrType::en attrtypeen;
         VLifetime::en lifetime;
+        VStrength::en strength;
 
 #include "V3Ast__gen_yystype.h"
     };
@@ -216,6 +217,7 @@ public:
     }
     int lexKwdLastState() const { return m_lexKwdLast; }
     static const char* tokenName(int tok);
+    static bool isStrengthToken(int tok);
 
     void ppPushText(const string& text) {
         m_ppBuffers.push_back(text);
diff --git a/src/V3PreLex.l b/src/V3PreLex.l
index bfe69e7c7..a83a55db9 100644
--- a/src/V3PreLex.l
+++ b/src/V3PreLex.l
@@ -126,7 +126,7 @@ bom             [\357\273\277]
                           if (LEXP->m_protBytes > 0) {
                               LEXP->curFilelinep()->v3warn(BADSTDPRAGMA, "multiple `pragma protected encoding sections");
                           }
-                          res = sscanf(yytext + strlen("encoding"), " = (enctype = \"%15[A-Za-z0-9]\", line_length = %d, bytes = %d)", &enctype[0], &LEXP->m_protLength, &LEXP->m_protBytes);
+                          res = sscanf(yytext + std::strlen("encoding"), " = (enctype = \"%15[A-Za-z0-9]\", line_length = %d, bytes = %d)", &enctype[0], &LEXP->m_protLength, &LEXP->m_protBytes);
                           if (res == 0)
                               LEXP->curFilelinep()->v3warn(BADSTDPRAGMA, "`pragma protected encoding must have an \"enctype\" field");
                           LEXP->m_encType = !VL_STRCASECMP(enctype, "uuencode") ? Enctype::UUENCODE :
@@ -242,7 +242,7 @@ bom             [\357\273\277]
 <INITIAL,STRIFY>"`__LINE__"     { FL_FWDC;
                           static char buf[25];
                           VL_SNPRINTF(buf, 25, "%d", LEXP->curFilelinep()->lastLineno());
-                          yytext = buf; yyleng = strlen(yytext);
+                          yytext = buf; yyleng = std::strlen(yytext);
                           return VP_TEXT; }
 
         /* Pass-through strings */
diff --git a/src/V3PreProc.cpp b/src/V3PreProc.cpp
index 59ba4398b..0cf66dc24 100644
--- a/src/V3PreProc.cpp
+++ b/src/V3PreProc.cpp
@@ -395,7 +395,7 @@ string V3PreProcImp::commentCleanup(const string& text) {
 }
 
 bool V3PreProcImp::commentTokenMatch(string& cmdr, const char* strg) {
-    int len = strlen(strg);
+    int len = std::strlen(strg);
     if (VString::startsWith(cmdr, strg) && (cmdr[len] == '\0' || isspace(cmdr[len]))) {
         if (isspace(cmdr[len])) len++;
         cmdr = cmdr.substr(len);
@@ -425,27 +425,27 @@ void V3PreProcImp::comment(const string& text) {
     bool synth = false;
     bool vlcomment = false;
     if ((cp[0] == 'v' || cp[0] == 'V') && VString::startsWith(cp + 1, "erilator")) {
-        cp += strlen("verilator");
+        cp += std::strlen("verilator");
         if (*cp == '_') {
             fileline()->v3error("Extra underscore in meta-comment;"
                                 " use /*verilator {...}*/ not /*verilator_{...}*/");
         }
         vlcomment = true;
     } else if (VString::startsWith(cp, "synopsys")) {
-        cp += strlen("synopsys");
+        cp += std::strlen("synopsys");
         synth = true;
         if (*cp == '_') {
             fileline()->v3error("Extra underscore in meta-comment;"
                                 " use /*synopsys {...}*/ not /*synopsys_{...}*/");
         }
     } else if (VString::startsWith(cp, "cadence")) {
-        cp += strlen("cadence");
+        cp += std::strlen("cadence");
         synth = true;
     } else if (VString::startsWith(cp, "pragma")) {
-        cp += strlen("pragma");
+        cp += std::strlen("pragma");
         synth = true;
     } else if (VString::startsWith(cp, "ambit synthesis")) {
-        cp += strlen("ambit synthesis");
+        cp += std::strlen("ambit synthesis");
         synth = true;
     } else {
         return;
@@ -478,7 +478,7 @@ void V3PreProcImp::comment(const string& text) {
         string::size_type pos;
         if ((pos = cmd.find("public_flat_rw")) != string::npos) {
             // "/*verilator public_flat_rw @(foo) */" -> "/*verilator public_flat_rw*/ @(foo)"
-            cmd = cmd.substr(pos + strlen("public_flat_rw"));
+            cmd = cmd.substr(pos + std::strlen("public_flat_rw"));
             while (isspace(cmd[0])) cmd = cmd.substr(1);
             if (!printed) insertUnreadback("/*verilator public_flat_rw*/ " + cmd + " /**/");
         } else {
@@ -1593,7 +1593,7 @@ string V3PreProcImp::getline() {
     if (isEof()) return "";
     const char* rtnp;
     bool gotEof = false;
-    while (nullptr == (rtnp = strchr(m_lineChars.c_str(), '\n')) && !gotEof) {
+    while (nullptr == (rtnp = std::strchr(m_lineChars.c_str(), '\n')) && !gotEof) {
         string buf;
         const int tok = getFinalToken(buf /*ref*/);
         if (debug() >= 5) {
diff --git a/src/V3String.cpp b/src/V3String.cpp
index 9d20bd078..1a42ee2e7 100644
--- a/src/V3String.cpp
+++ b/src/V3String.cpp
@@ -150,7 +150,7 @@ double VString::parseDouble(const string& str, bool* successp) {
     char* endp = strgp;
     const double d = strtod(strgp, &endp);
     const size_t parsed_len = endp - strgp;
-    if (parsed_len != strlen(strgp)) {
+    if (parsed_len != std::strlen(strgp)) {
         if (successp) *successp = false;
     }
     VL_DO_DANGLING(delete[] strgp, strgp);
@@ -402,7 +402,7 @@ void VHashSha256::selfTest() {
 
 string VName::dehash(const string& in) {
     static const char VHSH[] = "__Vhsh";
-    static const size_t DOT_LEN = strlen("__DOT__");
+    static const size_t DOT_LEN = std::strlen("__DOT__");
     std::string dehashed;
 
     // Need to split 'in' into components separated by __DOT__, 'last_dot_pos'
diff --git a/src/V3Subst.cpp b/src/V3Subst.cpp
index ef7562ac5..ce43a7fd0 100644
--- a/src/V3Subst.cpp
+++ b/src/V3Subst.cpp
@@ -359,6 +359,13 @@ private:
     }
     virtual void visit(AstVar*) override {}
     virtual void visit(AstConst*) override {}
+    virtual void visit(AstModule* nodep) override {
+        ++m_ops;
+        if (!nodep->isSubstOptimizable()) m_ops = SUBST_MAX_OPS_NA;
+        iterateChildren(nodep);
+        // Reduce peak memory usage by reclaiming the edited AstNodes
+        doDeletes();
+    }
     virtual void visit(AstNode* nodep) override {
         m_ops++;
         if (!nodep->isSubstOptimizable()) m_ops = SUBST_MAX_OPS_NA;
diff --git a/src/V3Tristate.cpp b/src/V3Tristate.cpp
index b5e983978..733d4ad74 100644
--- a/src/V3Tristate.cpp
+++ b/src/V3Tristate.cpp
@@ -55,6 +55,33 @@
 // duplicating vars and logic that is common between each instance of a
 // module.
 //
+//
+// Another thing done in this phase is signal strength handling.
+// Currently they are only supported in assignments and only in case when the strongest assignment
+// has constant with all bits equal on the RHS. It is the case when they can be statically
+// resolved.
+//
+// Static resolution is done in the following way:
+// - The assignment of value 0 (size may be greater than 1), that has greatest strength (the
+// one corresponding to 0) of all other assignments of 0, has to be found.
+// - The same is done for value '1 and strength corresponding to value 1.
+// - The greater of these two strengths is chosen. If they are equal the one that corresponds
+// to 1 is taken as the greatest.
+// - All assignments, that have strengths weaker or equal to the one that was found before, are
+// removed. They are the assignments with constants on the RHS and also all assignments that have
+// both strengths non-greater that the one was found, because they are weaker no matter what is on
+// RHS.
+//
+// All assignments that are stronger than the one with strongest constant are left as they are.
+//
+// There is a possible problem with equally strong assignments, because multiple assignments with
+// the same strength, but different values should result in x value, but these values are
+// unsupported.
+//
+// Singal strength can also be used in simple logic gates parsed as assignments (see verilog.y),
+// but these gates are then either removed (if they are weaker than the strongest constant) or
+// handled as the gates witout signal strengths are handled now. In other words, gate with greater
+// strength won't properly overwrite weaker driver.
 //*************************************************************************
 
 #include "config_build.h"
@@ -340,6 +367,8 @@ class TristateVisitor final : public TristateBaseVisitor {
     // TYPES
     using RefVec = std::vector<AstVarRef*>;
     using VarMap = std::unordered_map<AstVar*, RefVec*>;
+    using Assigns = std::vector<AstAssignW*>;
+    using VarToAssignsMap = std::map<AstVar*, Assigns>;
     enum : uint8_t {
         U2_GRAPHING = 1,  // bit[0] if did m_graphing visit
         U2_NONGRAPH = 2,  // bit[1] if did !m_graphing visit
@@ -352,6 +381,7 @@ class TristateVisitor final : public TristateBaseVisitor {
     AstNodeModule* m_modp = nullptr;  // Current module
     AstCell* m_cellp = nullptr;  // current cell
     VarMap m_lhsmap;  // Tristate left-hand-side driver map
+    VarToAssignsMap m_assigns;  // Assigns in current module
     int m_unique = 0;
     bool m_alhs = false;  // On LHS of assignment
     const AstNode* m_logicp = nullptr;  // Current logic being built
@@ -636,6 +666,117 @@ class TristateVisitor final : public TristateBaseVisitor {
         nodep->addStmtp(assp);
     }
 
+    void addToAssignmentList(AstAssignW* nodep) {
+        if (AstVarRef* const varRefp = VN_CAST(nodep->lhsp(), VarRef)) {
+            if (varRefp->varp()->isNet()) {
+                m_assigns[varRefp->varp()].push_back(nodep);
+            } else if (nodep->strengthSpecp()) {
+                if (!varRefp->varp()->isNet())
+                    nodep->v3warn(E_UNSUPPORTED, "Unsupported: Signal strengths are unsupported "
+                                                 "on the following variable type: "
+                                                     << varRefp->varp()->varType());
+
+                nodep->strengthSpecp()->unlinkFrBack()->deleteTree();
+            }
+        } else if (nodep->strengthSpecp()) {
+            nodep->v3warn(E_UNSUPPORTED,
+                          "Unsupported: Assignments with signal strength with LHS of type: "
+                              << nodep->lhsp()->prettyTypeName());
+        }
+    }
+
+    uint8_t getStrength(AstAssignW* const nodep, bool value) {
+        if (AstStrengthSpec* const strengthSpec = nodep->strengthSpecp()) {
+            return value ? strengthSpec->strength1() : strengthSpec->strength0();
+        }
+        return VStrength::STRONG;  // default strength is strong
+    }
+
+    bool assignmentOfValueOnAllBits(AstAssignW* const nodep, bool value) {
+        if (AstConst* const constp = VN_CAST(nodep->rhsp(), Const)) {
+            const V3Number num = constp->num();
+            return value ? num.isEqAllOnes() : num.isEqZero();
+        }
+        return false;
+    }
+
+    AstAssignW* getStrongestAssignmentOfValue(const Assigns& assigns, bool value) {
+        auto maxIt = std::max_element(
+            assigns.begin(), assigns.end(), [&](AstAssignW* ap, AstAssignW* bp) {
+                bool valuesOnRhsA = assignmentOfValueOnAllBits(ap, value);
+                bool valuesOnRhsB = assignmentOfValueOnAllBits(bp, value);
+                if (!valuesOnRhsA) return valuesOnRhsB;
+                if (!valuesOnRhsB) return false;
+                return getStrength(ap, value) < getStrength(bp, value);
+            });
+        // If not all assignments have const with all bits equal to value on the RHS,
+        // std::max_element will return one of them anyway, so it has to be checked before
+        // returning
+        return assignmentOfValueOnAllBits(*maxIt, value) ? *maxIt : nullptr;
+    }
+
+    void removeWeakerAssignments(Assigns& assigns) {
+        // Weaker assignments are these assignments that can't change the final value of the net.
+        // If the value of the RHS is known, only strength corresponding to its value is taken into
+        // account. Assignments of constants that have bits both 0 and 1 are skipped here, because
+        // it would involve handling parts of bits separately.
+
+        // First, the strongest assignment, that has value on the RHS consisting of only 1 or only
+        // 0, has to be found.
+        AstAssignW* const strongest0p = getStrongestAssignmentOfValue(assigns, 0);
+        AstAssignW* const strongest1p = getStrongestAssignmentOfValue(assigns, 1);
+        AstAssignW* strongestp = nullptr;
+        uint8_t greatestKnownStrength = 0;
+        const auto getIfStrongest = [&](AstAssignW* const strongestCandidatep, bool value) {
+            if (!strongestCandidatep) return;
+            uint8_t strength = getStrength(strongestCandidatep, value);
+            if (strength >= greatestKnownStrength) {
+                greatestKnownStrength = strength;
+                strongestp = strongestCandidatep;
+            }
+        };
+        getIfStrongest(strongest0p, 0);
+        getIfStrongest(strongest1p, 1);
+
+        if (strongestp) {
+            // Then all weaker assignments can be safely removed.
+            // Assignments of the same strength are also removed, because duplicates aren't needed.
+            // One problem is with 2 assignments of different values and equal strengths. It should
+            // result in assignment of x value, but these values aren't supported now.
+            auto removedIt
+                = std::remove_if(assigns.begin(), assigns.end(), [&](AstAssignW* assignp) {
+                      if (assignp == strongestp) return false;
+                      const uint8_t strength0 = getStrength(assignp, 0);
+                      const uint8_t strength1 = getStrength(assignp, 1);
+                      const bool toRemove = (strength0 <= greatestKnownStrength
+                                             && strength1 <= greatestKnownStrength)
+                                            || (strength0 <= greatestKnownStrength
+                                                && assignmentOfValueOnAllBits(assignp, 0))
+                                            || (strength1 <= greatestKnownStrength
+                                                && assignmentOfValueOnAllBits(assignp, 1));
+                      if (toRemove) {
+                          // Don't propagate tristate if its assignment is removed.
+                          TristateVertex* const vertexp
+                              = reinterpret_cast<TristateVertex*>(assignp->rhsp()->user5p());
+                          if (vertexp) vertexp->isTristate(false);
+                          VL_DO_DANGLING(pushDeletep(assignp->unlinkFrBack()), assignp);
+                          return true;
+                      }
+                      return false;
+                  });
+            assigns.erase(removedIt, assigns.end());
+        }
+    }
+
+    void resolveMultipleNetAssignments() {
+        for (auto& varpAssigns : m_assigns) {
+            if (varpAssigns.second.size() > 1) {
+                // first the static resolution is tried
+                removeWeakerAssignments(varpAssigns.second);
+            }
+        }
+    }
+
     // VISITORS
     virtual void visit(AstConst* nodep) override {
         UINFO(9, dbgState() << nodep << endl);
@@ -889,6 +1030,8 @@ class TristateVisitor final : public TristateBaseVisitor {
 
     void visitAssign(AstNodeAssign* nodep) {
         if (m_graphing) {
+            if (AstAssignW* assignWp = VN_CAST(nodep, AssignW)) addToAssignmentList(assignWp);
+
             if (nodep->user2() & U2_GRAPHING) return;
             VL_RESTORER(m_logicp);
             m_logicp = nodep;
@@ -1373,6 +1516,7 @@ class TristateVisitor final : public TristateBaseVisitor {
         VL_RESTORER(m_graphing);
         VL_RESTORER(m_unique);
         VL_RESTORER(m_lhsmap);
+        VL_RESTORER(m_assigns);
         // Not preserved, needs pointer instead: TristateGraph origTgraph = m_tgraph;
         UASSERT_OBJ(m_tgraph.empty(), nodep, "Unsupported: NodeModule under NodeModule");
         {
@@ -1382,6 +1526,7 @@ class TristateVisitor final : public TristateBaseVisitor {
             m_unique = 0;
             m_logicp = nullptr;
             m_lhsmap.clear();
+            m_assigns.clear();
             m_modp = nodep;
             // Walk the graph, finding all variables and tristate constructs
             {
@@ -1389,6 +1534,8 @@ class TristateVisitor final : public TristateBaseVisitor {
                 iterateChildren(nodep);
                 m_graphing = false;
             }
+            // resolve multiple net assignments and signal strengths
+            resolveMultipleNetAssignments();
             // Use graph to find tristate signals
             m_tgraph.graphWalk(nodep);
             // Build the LHS drivers map for this module
diff --git a/src/V3Waiver.cpp b/src/V3Waiver.cpp
index 42d222fe8..41a07c1ff 100644
--- a/src/V3Waiver.cpp
+++ b/src/V3Waiver.cpp
@@ -6,9 +6,10 @@
 //
 //*************************************************************************
 //
-// Copyright 2020 by Wilson Snyder. This program is free software; you can
-// redistribute it and/or modify it under the terms of either the GNU Lesser
-// General Public License Version 3 or the Perl Artistic License Version 2.0.
+// Copyright 2020-2022 by Wilson Snyder. This program is free software; you
+// can redistribute it and/or modify it under the terms of either the GNU
+// Lesser General Public License Version 3 or the Perl Artistic License
+// Version 2.0.
 // SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
 //
 //*************************************************************************
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index a2b6ace1e..1e625d4f7 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -538,7 +538,7 @@ private:
                 || VN_IS(vdtypep, DynArrayDType)  //
                 || VN_IS(vdtypep, QueueDType)) {
                 nodep->v3warn(E_UNSUPPORTED, "Unsupported: Concatenation to form "
-                                                 << vdtypep->prettyDTypeNameQ() << "data type");
+                                                 << vdtypep->prettyDTypeNameQ() << " data type");
             }
 
             iterateCheckSizedSelf(nodep, "LHS", nodep->lhsp(), SELF, BOTH);
@@ -3256,6 +3256,7 @@ private:
                     nodep->dtypeFrom(ftaskp);
                     nodep->classOrPackagep(classp);
                     if (VN_IS(ftaskp, Task)) nodep->makeStatement();
+                    processFTaskRefArgs(nodep);
                 }
                 return;
             }
@@ -5910,7 +5911,8 @@ private:
                     "Node has no type");  // Perhaps forgot to do a prelim visit on it?
         //
         // For DOUBLE under a logical op, add implied test against zero, never a warning
-        if (underp && underp->isDouble()) {
+        AstNodeDType* const underVDTypep = underp ? underp->dtypep()->skipRefp() : nullptr;
+        if (underp && underVDTypep->isDouble()) {
             UINFO(6, "   spliceCvtCmpD0: " << underp << endl);
             VNRelinker linker;
             underp->unlinkFrBack(&linker);
@@ -5918,13 +5920,12 @@ private:
                 = new AstNeqD(nodep->fileline(), underp,
                               new AstConst(nodep->fileline(), AstConst::RealDouble(), 0.0));
             linker.relink(newp);
-        } else if (VN_IS(underp->dtypep(), ClassRefDType)
-                   || (VN_IS(underp->dtypep(), BasicDType)
-                       && VN_AS(underp->dtypep(), BasicDType)->keyword()
-                              == VBasicDTypeKwd::CHANDLE)) {
+        } else if (VN_IS(underVDTypep, ClassRefDType)
+                   || (VN_IS(underVDTypep, BasicDType)
+                       && VN_AS(underVDTypep, BasicDType)->keyword() == VBasicDTypeKwd::CHANDLE)) {
             // Allow warning-free "if (handle)"
             VL_DO_DANGLING(fixWidthReduce(underp), underp);  // Changed
-        } else if (!underp->dtypep()->basicp()) {
+        } else if (!underVDTypep->basicp()) {
             nodep->v3error("Logical operator " << nodep->prettyTypeName()
                                                << " expects a non-complex data type on the "
                                                << side << ".");
@@ -6065,7 +6066,7 @@ private:
             }
             if ((VN_IS(nodep, Add) && underp->width() == 1 && underp->isOne())
                 || (VN_IS(nodep, Sub) && underp->width() == 1 && underp->isOne()
-                    && 0 == strcmp(side, "RHS"))) {
+                    && 0 == std::strcmp(side, "RHS"))) {
                 // "foo + 1'b1", or "foo - 1'b1" are very common, people assume
                 // they extend correctly
                 warnOn = false;
diff --git a/src/astgen b/src/astgen
index 44529a0e4..f8860dce0 100755
--- a/src/astgen
+++ b/src/astgen
@@ -8,9 +8,125 @@ import re
 import sys
 # from pprint import pprint, pformat
 
-Types = []
-Classes = {}
-Children = {}
+
+class Node:
+    def __init__(self, name, superClass):
+        self._name = name
+        self._superClass = superClass
+        self._subClasses = []  # Initially list, but tuple after completion
+        self._allSuperClasses = None  # Computed on demand after completion
+        self._allSubClasses = None  # Computed on demand after completion
+        self._typeId = None  # Concrete type identifier number for leaf classes
+        self._typeIdMin = None  # Lowest type identifier number for class
+        self._typeIdMax = None  # Highest type identifier number for class
+
+    @property
+    def name(self):
+        return self._name
+
+    @property
+    def superClass(self):
+        return self._superClass
+
+    @property
+    def isCompleted(self):
+        return isinstance(self._subClasses, tuple)
+
+    # Pre completion methods
+    def addSubClass(self, subClass):
+        assert not self.isCompleted
+        self._subClasses.append(subClass)
+
+    # Computes derived properties over entire class hierarchy.
+    # No more changes to the hierarchy are allowed once this was called
+    def complete(self, typeId=0):
+        assert not self.isCompleted
+        # Sort sub-classes and convert to tuple, which marks completion
+        self._subClasses = tuple(sorted(self._subClasses,
+                                        key=lambda _: _.name))
+        # Leaves
+        if self.isLeaf:
+            self._typeId = typeId
+            return typeId + 1
+
+        # Non-leaves
+        for subClass in self._subClasses:
+            typeId = subClass.complete(typeId)
+        return typeId
+
+    # Post completion methods
+    @property
+    def subClasses(self):
+        assert self.isCompleted
+        return self._subClasses
+
+    @property
+    def isRoot(self):
+        assert self.isCompleted
+        return self.superClass is None
+
+    @property
+    def isLeaf(self):
+        assert self.isCompleted
+        return not self.subClasses
+
+    @property
+    def allSuperClasses(self):
+        assert self.isCompleted
+        if self._allSuperClasses is None:
+            if self.superClass is None:
+                self._allSuperClasses = ()
+            else:
+                self._allSuperClasses = self.superClass.allSuperClasses + (
+                    self.superClass, )
+        return self._allSuperClasses
+
+    @property
+    def allSubClasses(self):
+        assert self.isCompleted
+        if self._allSubClasses is None:
+            if self.isLeaf:
+                self._allSubClasses = ()
+            else:
+                self._allSubClasses = self.subClasses + tuple(
+                    _ for subClass in self.subClasses
+                    for _ in subClass.allSubClasses)
+        return self._allSubClasses
+
+    @property
+    def typeId(self):
+        assert self.isCompleted
+        assert self.isLeaf
+        return self._typeId
+
+    @property
+    def typeIdMin(self):
+        assert self.isCompleted
+        if self.isLeaf:
+            return self.typeId
+        if self._typeIdMin is None:
+            self._typeIdMin = min(_.typeIdMin for _ in self.allSubClasses)
+        return self._typeIdMin
+
+    @property
+    def typeIdMax(self):
+        assert self.isCompleted
+        if self.isLeaf:
+            return self.typeId
+        if self._typeIdMax is None:
+            self._typeIdMax = max(_.typeIdMax for _ in self.allSubClasses)
+        return self._typeIdMax
+
+    def isSubClassOf(self, other):
+        assert self.isCompleted
+        if self is other:
+            return True
+        return self in other.allSubClasses
+
+
+Nodes = {}
+SortedNodes = None
+
 ClassRefs = {}
 Stages = {}
 
@@ -111,7 +227,7 @@ class Cpt:
                 self.error("Can't parse from function: " + func)
             typen = match.group(1)
             subnodes = match.group(2)
-            if not subclasses_of(typen):
+            if Nodes[typen].isRoot:
                 self.error("Unknown AstNode typen: " + typen + ": in " + func)
 
             mif = ""
@@ -166,7 +282,7 @@ class Cpt:
         elif match_skip:
             typen = match_skip.group(1)
             self.tree_skip_visit[typen] = 1
-            if typen not in Classes:
+            if typen not in Nodes:
                 self.error("Unknown node type: " + typen)
 
         else:
@@ -296,12 +412,13 @@ class Cpt:
         self.print(
             "    // Bottom class up, as more simple transforms are generally better\n"
         )
-        for typen in sorted(Classes.keys()):
+        for node in SortedNodes:
             out_for_type_sc = []
             out_for_type = []
-            bases = subclasses_of(typen)
-            bases.append(typen)
-            for base in bases:
+            classes = list(node.allSuperClasses)
+            classes.append(node)
+            for base in classes:
+                base = base.name
                 if base not in self.treeop:
                     continue
                 for typefunc in self.treeop[base]:
@@ -328,23 +445,23 @@ class Cpt:
             if len(out_for_type_sc) > 0:  # Short-circuited types
                 self.print(
                     "    // Generated by astgen with short-circuiting\n" +
-                    "    virtual void visit(Ast" + typen +
+                    "    virtual void visit(Ast" + node.name +
                     "* nodep) override {\n" +
                     "      iterateAndNextNull(nodep->lhsp());\n" +
                     "".join(out_for_type_sc))
                 if out_for_type[0]:
                     self.print("      iterateAndNextNull(nodep->rhsp());\n")
-                    if is_subclass_of(typen, "NodeTriop"):
+                    if node.isSubClassOf(Nodes["NodeTriop"]):
                         self.print(
                             "      iterateAndNextNull(nodep->thsp());\n")
                     self.print("".join(out_for_type) + "    }\n")
             elif len(out_for_type) > 0:  # Other types with something to print
-                skip = typen in self.tree_skip_visit
+                skip = node.name in self.tree_skip_visit
                 gen = "Gen" if skip else ""
                 override = "" if skip else " override"
                 self.print(
                     "    // Generated by astgen\n" + "    virtual void visit" +
-                    gen + "(Ast" + typen + "* nodep)" + override + " {\n" +
+                    gen + "(Ast" + node.name + "* nodep)" + override + " {\n" +
                     ("" if skip else "        iterateChildren(nodep);\n") +
                     ''.join(out_for_type) + "    }\n")
 
@@ -368,11 +485,13 @@ def read_types(filename):
                 if re.search(r'Ast', supern) or classn == "AstNode":
                     classn = re.sub(r'^Ast', '', classn)
                     supern = re.sub(r'^Ast', '', supern)
-                    Classes[classn] = supern
-                    if supern != '':
-                        if supern not in Children:
-                            Children[supern] = {}
-                        Children[supern][classn] = 1
+                    if supern:
+                        superClass = Nodes[supern]
+                        node = Node(classn, superClass)
+                        Nodes[supern].addSubClass(node)
+                    else:
+                        node = Node(classn, None)
+                    Nodes[classn] = node
 
 
 def read_stages(filename):
@@ -424,37 +543,6 @@ def open_file(filename):
     return fh
 
 
-def subclasses_of(typen):
-    cllist = []
-    subclass = Classes[typen]
-    while True:
-        if subclass not in Classes:
-            break
-        cllist.append(subclass)
-        subclass = Classes[subclass]
-
-    cllist.reverse()
-    return cllist
-
-
-def children_of(typen):
-    cllist = []
-    todo = []
-    todo.append(typen)
-    while len(todo) != 0:
-        subclass = todo.pop(0)
-        if subclass in Children:
-            for child in sorted(Children[subclass].keys()):
-                todo.append(child)
-                cllist.append(child)
-
-    return cllist
-
-
-def is_subclass_of(typen, what):
-    return typen == what or (typen in children_of(what))
-
-
 # ---------------------------------------------------------------------
 
 
@@ -468,20 +556,19 @@ def write_report(filename):
             fh.write("  " + classn + "\n")
 
         fh.write("\nClasses:\n")
-        for typen in sorted(Classes.keys()):
-            fh.write("  class Ast%-17s\n" % typen)
+        for node in SortedNodes:
+            fh.write("  class Ast%-17s\n" % node.name)
             fh.write("    parent: ")
-            for subclass in subclasses_of(typen):
-                if subclass != 'Node':
-                    fh.write("Ast%-12s " % subclass)
+            for superClass in node.allSuperClasses:
+                if not superClass.isRoot:
+                    fh.write("Ast%-12s " % superClass.name)
             fh.write("\n")
             fh.write("    childs:  ")
-            for subclass in children_of(typen):
-                if subclass != 'Node':
-                    fh.write("Ast%-12s " % subclass)
+            for subClass in node.allSubClasses:
+                fh.write("Ast%-12s " % subClass.name)
             fh.write("\n")
-            if ("Ast" + typen) in ClassRefs:  # pylint: disable=superfluous-parens
-                refs = ClassRefs["Ast" + typen]
+            if ("Ast" + node.name) in ClassRefs:  # pylint: disable=superfluous-parens
+                refs = ClassRefs["Ast" + node.name]
                 fh.write("    newed:  ")
                 for stage in sorted(refs['newed'].keys(),
                                     key=lambda val: Stages[val]
@@ -500,27 +587,27 @@ def write_report(filename):
 def write_classes(filename):
     with open_file(filename) as fh:
         fh.write("class AstNode;\n")
-        for typen in sorted(Classes.keys()):
-            fh.write("class Ast%-17s // " % (typen + ";"))
-            for subclass in subclasses_of(typen):
-                fh.write("Ast%-12s " % subclass)
+        for node in SortedNodes:
+            fh.write("class Ast%-17s // " % (node.name + ";"))
+            for superClass in node.allSuperClasses:
+                fh.write("Ast%-12s " % superClass.name)
             fh.write("\n")
 
 
 def write_visitor_decls(filename):
     with open_file(filename) as fh:
-        for typen in sorted(Classes.keys()):
-            if typen != "Node":
-                fh.write("virtual void visit(Ast" + typen + "*);\n")
+        for node in SortedNodes:
+            if not node.isRoot:
+                fh.write("virtual void visit(Ast" + node.name + "*);\n")
 
 
 def write_visitor_defns(filename):
     with open_file(filename) as fh:
-        for typen in sorted(Classes.keys()):
-            if typen != "Node":
-                base = Classes[typen]
-                fh.write("void VNVisitor::visit(Ast" + typen +
-                         "* nodep) { visit(static_cast<Ast" + base +
+        for node in SortedNodes:
+            base = node.superClass
+            if base is not None:
+                fh.write("void VNVisitor::visit(Ast" + node.name +
+                         "* nodep) { visit(static_cast<Ast" + base.name +
                          "*>(nodep)); }\n")
 
 
@@ -528,75 +615,51 @@ def write_impl(filename):
     with open_file(filename) as fh:
         fh.write("\n")
         fh.write("// For internal use. They assume argument is not nullptr.\n")
-        for typen in sorted(Classes.keys()):
+        for node in SortedNodes:
             fh.write("template<> inline bool AstNode::privateTypeTest<Ast" +
-                     typen + ">(const AstNode* nodep) { ")
-            if typen == "Node":
+                     node.name + ">(const AstNode* nodep) { ")
+            if node.isRoot:
                 fh.write("return true; ")
             else:
                 fh.write("return ")
-                if re.search(r'^Node', typen):
+                if not node.isLeaf:
                     fh.write(
                         "static_cast<int>(nodep->type()) >= static_cast<int>(VNType::first"
-                        + typen + ") && ")
+                        + node.name + ") && ")
                     fh.write(
                         "static_cast<int>(nodep->type()) <= static_cast<int>(VNType::last"
-                        + typen + "); ")
+                        + node.name + "); ")
                 else:
-                    fh.write("nodep->type() == VNType::at" + typen + "; ")
+                    fh.write("nodep->type() == VNType::at" + node.name + "; ")
             fh.write("}\n")
 
 
-def write_type_enum(fh, typen, idx, processed, kind, indent):
-    # Skip this if it has already been processed
-    if typen in processed:
-        return idx
-    # Mark processed
-    processed[typen] = 1
-
-    # The last used index
-    last = None
-
-    if not re.match(r'^Node', typen):
-        last = idx
-        if kind == "concrete-enum":
-            fh.write(" " * (indent * 4) + "at" + typen + " = " + str(idx) +
-                     ",\n")
-        elif kind == "concrete-ascii":
-            fh.write(" " * (indent * 4) + "\"" + typen.upper() + "\",\n")
-        idx += 1
-    elif kind == "abstract-enum":
-        fh.write(" " * (indent * 4) + "first" + typen + " = " + str(idx) +
-                 ",\n")
-
-    if typen in Children:
-        for child in sorted(Children[typen].keys()):
-            (idx, last) = write_type_enum(fh, child, idx, processed, kind,
-                                          indent)
-
-    if re.match(r'^Node', typen) and kind == "abstract-enum":
-        fh.write(" " * (indent * 4) + "last" + typen + " = " + str(last) +
-                 ",\n")
-
-    return [idx, last]
-
-
 def write_types(filename):
     with open_file(filename) as fh:
         fh.write("    enum en : uint16_t {\n")
-        (final, ignored) = write_type_enum(  # pylint: disable=W0612
-            fh, "Node", 0, {}, "concrete-enum", 2)
-        fh.write("        _ENUM_END = " + str(final) + "\n")
+        for node in sorted(filter(lambda _: _.isLeaf, SortedNodes),
+                           key=lambda _: _.typeId):
+            fh.write("        at" + node.name + " = " + str(node.typeId) +
+                     ",\n")
+        fh.write("        _ENUM_END = " + str(Nodes["Node"].typeIdMax + 1) +
+                 "\n")
         fh.write("    };\n")
 
         fh.write("    enum bounds : uint16_t {\n")
-        write_type_enum(fh, "Node", 0, {}, "abstract-enum", 2)
+        for node in sorted(filter(lambda _: not _.isLeaf, SortedNodes),
+                           key=lambda _: _.typeIdMin):
+            fh.write("        first" + node.name + " = " +
+                     str(node.typeIdMin) + ",\n")
+            fh.write("        last" + node.name + " = " + str(node.typeIdMax) +
+                     ",\n")
         fh.write("        _BOUNDS_END\n")
         fh.write("    };\n")
 
         fh.write("    const char* ascii() const {\n")
         fh.write("        static const char* const names[_ENUM_END + 1] = {\n")
-        write_type_enum(fh, "Node", 0, {}, "concrete-ascii", 3)
+        for node in sorted(filter(lambda _: _.isLeaf, SortedNodes),
+                           key=lambda _: _.typeId):
+            fh.write("            \"" + node.name.upper() + "\",\n")
         fh.write("            \"_ENUM_END\"\n")
         fh.write("        };\n")
         fh.write("        return names[m_e];\n")
@@ -605,45 +668,21 @@ def write_types(filename):
 
 def write_yystype(filename):
     with open_file(filename) as fh:
-        for typen in sorted(Classes.keys()):
-            fh.write("Ast{t}* {m}p;\n".format(t=typen,
-                                              m=typen[0].lower() + typen[1:]))
+        for node in SortedNodes:
+            fh.write("Ast{t}* {m}p;\n".format(t=node.name,
+                                              m=node.name[0].lower() +
+                                              node.name[1:]))
 
 
 def write_macros(filename):
     with open_file(filename) as fh:
-        typen = "None"
-        base = "None"
-
-        in_filename = "V3AstNodes.h"
-        ifile = Args.I + "/" + in_filename
-        with open(ifile) as ifh:
-            for (lineno, line) in enumerate(ifh, 1):
-                # Drop expanded macro definitions - but keep empty line so compiler
-                # message locations are accurate
-                line = re.sub(r'^\s*#(define|undef)\s+ASTGEN_.*$', '', line)
-
-                # Track current node type and base class
-                match = re.search(
-                    r'\s*class\s*Ast(\S+)\s*(final|VL_NOT_FINAL)?\s*:\s*(public)?\s*(AstNode\S*)',
-                    line)
-                if match:
-                    typen = match.group(1)
-                    base = match.group(4)
-                    if not typen.startswith("Node"):
-                        macro = "#define ASTGEN_SUPER_{t}(...) {b}(VNType::at{t}, __VA_ARGS__)\n" \
-                                .format(b=base, t=typen)
-                        fh.write(macro)
-
-                match = re.search(r"ASTGEN_SUPER_(\w+)", line)
-                if match:
-                    if typen != match.group(1):
-                        print((
-                            "V3AstNodes.h:{l} ERROR: class Ast{t} calls wrong superclass "
-                            +
-                            "constructor macro (should call ASTGEN_SUPER_{t})"
-                        ).format(l=lineno, t=typen))
-                        sys.exit(1)
+        for node in SortedNodes:
+            # Only care about leaf classes
+            if not node.isLeaf:
+                continue
+            fh.write(
+                "#define ASTGEN_SUPER_{t}(...) Ast{b}(VNType::at{t}, __VA_ARGS__)\n"
+                .format(t=node.name, b=node.superClass.name))
 
 
 ######################################################################
@@ -673,19 +712,24 @@ Args = parser.parse_args()
 
 read_types(Args.I + "/V3Ast.h")
 read_types(Args.I + "/V3AstNodes.h")
-for typen in sorted(Classes.keys()):
+
+# Compute derived properties over the whole AstNode hierarchy
+Nodes["Node"].complete()
+
+SortedNodes = tuple(map(lambda _: Nodes[_], sorted(Nodes.keys())))
+
+for node in SortedNodes:
     # Check all leaves are not AstNode* and non-leaves are AstNode*
-    children = children_of(typen)
-    if re.match(r'^Node', typen):
-        if len(children) == 0:
+    if re.match(r'^Node', node.name):
+        if node.isLeaf:
             sys.exit(
                 "%Error: Final AstNode subclasses must not be named AstNode*: Ast"
-                + typen)
+                + node.name)
     else:
-        if len(children) != 0:
+        if not node.isLeaf:
             sys.exit(
                 "%Error: Non-final AstNode subclasses must be named AstNode*: Ast"
-                + typen)
+                + node.name)
 
 read_stages(Args.I + "/Verilator.cpp")
 
diff --git a/src/verilog.l b/src/verilog.l
index 798b44ef3..2f32764ac 100644
--- a/src/verilog.l
+++ b/src/verilog.l
@@ -327,8 +327,8 @@ vnum    {vnum1}|{vnum2}|{vnum3}|{vnum4}|{vnum5}
   "forever"             { FL; return yFOREVER; }
   "fork"                { FL; return yFORK; }
   "function"            { FL; return yFUNCTION; }
-  "highz0"              { FL; return ygenSTRENGTH; }
-  "highz1"              { FL; return ygenSTRENGTH; }
+  "highz0"              { FL; return yHIGHZ0; }
+  "highz1"              { FL; return yHIGHZ1; }
   "if"                  { FL; return yIF; }
   "initial"             { FL; return yINITIAL; }
   "inout"               { FL; return yINOUT; }
@@ -352,8 +352,8 @@ vnum    {vnum1}|{vnum2}|{vnum3}|{vnum4}|{vnum5}
   "pmos"                { FL; return yPMOS; }
   "posedge"             { FL; return yPOSEDGE; }
   "primitive"           { FL; return yPRIMITIVE; }
-  "pull0"               { FL; return ygenSTRENGTH; }
-  "pull1"               { FL; return ygenSTRENGTH; }
+  "pull0"               { FL; return yPULL0; }
+  "pull1"               { FL; return yPULL1; }
   "pulldown"            { FL; return yPULLDOWN; }
   "pullup"              { FL; return yPULLUP; }
   "rcmos"               { FL; return yRCMOS; }
@@ -371,8 +371,8 @@ vnum    {vnum1}|{vnum2}|{vnum3}|{vnum4}|{vnum5}
   "small"               { FL; return ygenSTRENGTH; }
   "specify"             { FL; return ySPECIFY; }
   "specparam"           { FL; return ySPECPARAM; }
-  "strong0"             { FL; return ygenSTRENGTH; }
-  "strong1"             { FL; return ygenSTRENGTH; }
+  "strong0"             { FL; return ySTRONG0; }
+  "strong1"             { FL; return ySTRONG1; }
   "supply0"             { FL; return ySUPPLY0; }
   "supply1"             { FL; return ySUPPLY1; }
   "table"               { FL; yy_push_state(TABLE); return yTABLE; }
@@ -390,8 +390,8 @@ vnum    {vnum1}|{vnum2}|{vnum3}|{vnum4}|{vnum5}
   "vectored"            { FL; return yVECTORED; }
   "wait"                { FL; return yWAIT; }
   "wand"                { FL; return yWAND; }
-  "weak0"               { FL; return ygenSTRENGTH; }
-  "weak1"               { FL; return ygenSTRENGTH; }
+  "weak0"               { FL; return yWEAK0; }
+  "weak1"               { FL; return yWEAK1; }
   "while"               { FL; return yWHILE; }
   "wire"                { FL; return yWIRE; }
   "wor"                 { FL; return yWOR; }
@@ -1008,7 +1008,7 @@ vnum    {vnum1}|{vnum2}|{vnum3}|{vnum4}|{vnum5}
                                           return yaT_RESETALL; }  // Rest handled by preproc
   "`suppress_faults"                    { FL_FWD; FL_BRK; }  // Verilog-XL compatibility
   "`timescale"{ws}+[^\n\r]*             { FL; PARSEP->lexTimescaleParse(yylval.fl,
-                                                                        yytext + strlen("`timescale"));
+                                                                        yytext + std::strlen("`timescale"));
                                           FL_BRK; }
   "`unconnected_drive"{ws}+"pull0"      { FL; return yaT_UNCONNECTED_PULL0; }
   "`unconnected_drive"{ws}+"pull1"      { FL; return yaT_UNCONNECTED_PULL1; }
diff --git a/src/verilog.y b/src/verilog.y
index 3d9cbb88e..60f90255d 100644
--- a/src/verilog.y
+++ b/src/verilog.y
@@ -58,6 +58,13 @@
             assignp->timingControlp(nodep == assignsp ? delayp : delayp->cloneTree(false)); \
         } \
     }
+#define STRENGTHUNSUP(nodep) \
+    { \
+        if (nodep) { \
+            BBUNSUP((nodep->fileline()), "Unsupported: Strength specifier on this gate type"); \
+            nodep->deleteTree(); \
+        } \
+    }
 
 //======================================================================
 // Statics (for here only)
@@ -79,6 +86,7 @@ public:
     AstNodeDType* m_varDTypep = nullptr;  // Pointer to data type for next signal declaration
     AstNodeDType* m_memDTypep = nullptr;  // Pointer to data type for next member declaration
     AstNode* m_netDelayp = nullptr;  // Pointer to delay for next signal declaration
+    AstStrengthSpec* m_netStrengthp = nullptr;  // Pointer to strength for next net declaration
     AstNodeModule* m_modp = nullptr;  // Last module for timeunits
     bool m_pinAnsi = false;  // In ANSI port list
     FileLine* m_instModuleFl = nullptr;  // Fileline of module referenced for instantiations
@@ -183,6 +191,7 @@ public:
         m_varDTypep = dtypep;
     }
     void setNetDelay(AstNode* netDelayp) { m_netDelayp = netDelayp; }
+    void setNetStrength(AstStrengthSpec* netStrengthp) { m_netStrengthp = netStrengthp; }
     void pinPush() {
         m_pinStack.push(m_pinNum);
         m_pinNum = 1;
@@ -302,6 +311,16 @@ int V3ParseGrammar::s_modTypeImpNum = 0;
         if (nodep) nodep->deleteTree(); \
     }
 
+#define APPLY_STRENGTH_TO_LIST(beginp, strengthSpecNodep, typeToCast) \
+    { \
+        if (AstStrengthSpec* specp = VN_CAST(strengthSpecNodep, StrengthSpec)) { \
+            for (auto* nodep = beginp; nodep; nodep = nodep->nextp()) { \
+                auto* const assignp = VN_AS(nodep, typeToCast); \
+                assignp->strengthSpecp(nodep == beginp ? specp : specp->cloneTree(false)); \
+            } \
+        } \
+    }
+
 static void ERRSVKWD(FileLine* fileline, const string& tokname) {
     static int toldonce = 0;
     fileline->v3error(
@@ -557,6 +576,8 @@ BISONPRE_VERSION(3.7,%define api.header.include {"V3ParseBison.h"})
 %token<fl>              yGLOBAL__CLOCKING "global-then-clocking"
 %token<fl>              yGLOBAL__ETC    "global"
 %token<fl>              yGLOBAL__LEX    "global-in-lex"
+%token<fl>              yHIGHZ0         "highz0"
+%token<fl>              yHIGHZ1         "highz1"
 %token<fl>              yIF             "if"
 %token<fl>              yIFF            "iff"
 //UNSUP %token<fl>      yIGNORE_BINS    "ignore_bins"
@@ -611,6 +632,8 @@ BISONPRE_VERSION(3.7,%define api.header.include {"V3ParseBison.h"})
 %token<fl>              yPROGRAM        "program"
 %token<fl>              yPROPERTY       "property"
 %token<fl>              yPROTECTED      "protected"
+%token<fl>              yPULL0          "pull0"
+%token<fl>              yPULL1          "pull1"
 %token<fl>              yPULLDOWN       "pulldown"
 %token<fl>              yPULLUP         "pullup"
 %token<fl>              yPURE           "pure"
@@ -648,6 +671,8 @@ BISONPRE_VERSION(3.7,%define api.header.include {"V3ParseBison.h"})
 %token<fl>              ySTATIC__LEX    "static-in-lex"
 %token<fl>              ySTRING         "string"
 //UNSUP %token<fl>      ySTRONG         "strong"
+%token<fl>              ySTRONG0        "strong0"
+%token<fl>              ySTRONG1        "strong1"
 %token<fl>              ySTRUCT         "struct"
 %token<fl>              ySUPER          "super"
 %token<fl>              ySUPPLY0        "supply0"
@@ -701,6 +726,8 @@ BISONPRE_VERSION(3.7,%define api.header.include {"V3ParseBison.h"})
 //UNSUP %token<fl>      yWAIT_ORDER     "wait_order"
 %token<fl>              yWAND           "wand"
 //UNSUP %token<fl>      yWEAK           "weak"
+%token<fl>              yWEAK0          "weak0"
+%token<fl>              yWEAK1          "weak1"
 %token<fl>              yWHILE          "while"
 //UNSUP %token<fl>      yWILDCARD       "wildcard"
 %token<fl>              yWIRE           "wire"
@@ -1731,11 +1758,18 @@ parameter_port_declarationTypeFrontE: // IEEE: parameter_port_declaration w/o as
         ;
 
 net_declaration<nodep>:         // IEEE: net_declaration - excluding implict
-                net_declarationFront netSigList ';'     { $$ = $2; }
+                net_declarationFront netSigList ';'
+                        { $$ = $2;
+                          if (GRAMMARP->m_netStrengthp) {
+                              VL_DO_CLEAR(delete GRAMMARP->m_netStrengthp, GRAMMARP->m_netStrengthp = nullptr);
+                          }}
         ;
 
 net_declarationFront:           // IEEE: beginning of net_declaration
-                net_declRESET net_type   strengthSpecE net_scalaredE net_dataTypeE { VARDTYPE_NDECL($5); }
+                net_declRESET net_type driveStrengthE net_scalaredE net_dataTypeE
+                        { VARDTYPE_NDECL($5);
+                          GRAMMARP->setNetStrength(VN_CAST($3, StrengthSpec));
+                        }
         //UNSUP net_declRESET yINTERCONNECT signingE rangeListE { VARNET($2); VARDTYPE(x); }
         ;
 
@@ -2441,10 +2475,11 @@ module_common_item<nodep>:      // ==IEEE: module_common_item
         ;
 
 continuous_assign<nodep>:       // IEEE: continuous_assign
-                yASSIGN strengthSpecE delay_controlE assignList ';'
+                yASSIGN driveStrengthE delay_controlE assignList ';'
                 {
                     $$ = $4;
-                    PUT_DLYS_IN_ASSIGNS($3, $$);
+                    APPLY_STRENGTH_TO_LIST($4, $2, AssignW);
+                    PUT_DLYS_IN_ASSIGNS($3, $4);
                 }
         ;
 
@@ -2733,6 +2768,7 @@ netSig<varp>:                   // IEEE: net_decl_assignment -  one element from
         |       netId sigAttrListE '=' expr
                         { $$ = VARDONEA($<fl>1, *$1, nullptr, $2);
                           auto* const assignp = new AstAssignW{$3, new AstVarRef{$<fl>1, *$1, VAccess::WRITE}, $4};
+                          if (GRAMMARP->m_netStrengthp) assignp->strengthSpecp(GRAMMARP->m_netStrengthp->cloneTree(false));
                           if ($$->delayp()) assignp->timingControlp($$->delayp()->unlinkFrBack());  // IEEE 1800-2017 10.3.3
                           $$->addNext(assignp); }
         |       netId variable_dimensionList sigAttrListE
@@ -4715,22 +4751,22 @@ stream_expressionOrDataType<nodep>:     // IEEE: from streaming_concatenation
 // Gate declarations
 
 gateDecl<nodep>:
-                yBUF    delay_controlE gateBufList ';'          { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yBUFIF0 delay_controlE gateBufif0List ';'       { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yBUFIF1 delay_controlE gateBufif1List ';'       { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yNOT    delay_controlE gateNotList ';'          { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yNOTIF0 delay_controlE gateNotif0List ';'       { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yNOTIF1 delay_controlE gateNotif1List ';'       { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yAND  delay_controlE gateAndList ';'            { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yNAND delay_controlE gateNandList ';'           { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yOR   delay_controlE gateOrList ';'             { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yNOR  delay_controlE gateNorList ';'            { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yXOR  delay_controlE gateXorList ';'            { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yXNOR delay_controlE gateXnorList ';'           { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yPULLUP delay_controlE gatePullupList ';'       { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
+                yBUF      driveStrengthE delay_controlE gateBufList ';'        { $$ = $4; STRENGTHUNSUP($2); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yBUFIF0   driveStrengthE delay_controlE gateBufif0List ';'     { $$ = $4; STRENGTHUNSUP($2); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yBUFIF1   driveStrengthE delay_controlE gateBufif1List ';'     { $$ = $4; STRENGTHUNSUP($2); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yNOT      driveStrengthE delay_controlE gateNotList ';'        { $$ = $4; APPLY_STRENGTH_TO_LIST($4, $2, AssignW); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yNOTIF0   driveStrengthE delay_controlE gateNotif0List ';'     { $$ = $4; STRENGTHUNSUP($2); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yNOTIF1   driveStrengthE delay_controlE gateNotif1List ';'     { $$ = $4; STRENGTHUNSUP($2); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yAND      driveStrengthE delay_controlE gateAndList ';'        { $$ = $4; APPLY_STRENGTH_TO_LIST($4, $2, AssignW); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yNAND     driveStrengthE delay_controlE gateNandList ';'       { $$ = $4; APPLY_STRENGTH_TO_LIST($4, $2, AssignW); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yOR       driveStrengthE delay_controlE gateOrList ';'         { $$ = $4; APPLY_STRENGTH_TO_LIST($4, $2, AssignW); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yNOR      driveStrengthE delay_controlE gateNorList ';'        { $$ = $4; APPLY_STRENGTH_TO_LIST($4, $2, AssignW); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yXOR      driveStrengthE delay_controlE gateXorList ';'        { $$ = $4; APPLY_STRENGTH_TO_LIST($4, $2, AssignW); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yXNOR     driveStrengthE delay_controlE gateXnorList ';'       { $$ = $4; APPLY_STRENGTH_TO_LIST($4, $2, AssignW); PUT_DLYS_IN_ASSIGNS($3, $4); }
+        |       yPULLUP   delay_controlE gatePullupList ';'     { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
         |       yPULLDOWN delay_controlE gatePulldownList ';'   { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
-        |       yNMOS delay_controlE gateBufif1List ';'         { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }  // ~=bufif1, as don't have strengths yet
-        |       yPMOS delay_controlE gateBufif0List ';'         { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }  // ~=bufif0, as don't have strengths yet
+        |       yNMOS     delay_controlE gateBufif1List ';'     { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
+        |       yPMOS     delay_controlE gateBufif0List ';'     { $$ = $3; PUT_DLYS_IN_ASSIGNS($2, $3); }
         //
         |       yTRAN delay_controlE gateUnsupList ';'          { $$ = $3; GATEUNSUP($3,"tran"); } // Unsupported
         |       yRCMOS delay_controlE gateUnsupList ';'         { $$ = $3; GATEUNSUP($3,"rcmos"); } // Unsupported
@@ -4898,21 +4934,33 @@ gatePinExpr<nodep>:
                 expr                                    { $$ = GRAMMARP->createGatePin($1); }
         ;
 
-// This list is also hardcoded in VParseLex.l
-strength:                       // IEEE: strength0+strength1 - plus HIGHZ/SMALL/MEDIUM/LARGE
-                ygenSTRENGTH                            { BBUNSUP($1, "Unsupported: Verilog 1995 strength specifiers"); }
-        |       ySUPPLY0                                { BBUNSUP($1, "Unsupported: Verilog 1995 strength specifiers"); }
-        |       ySUPPLY1                                { BBUNSUP($1, "Unsupported: Verilog 1995 strength specifiers"); }
+strength0<strength>:
+                ySUPPLY0                                { $$ = VStrength::SUPPLY; }
+        |       ySTRONG0                                { $$ = VStrength::STRONG; }
+        |       yPULL0                                  { $$ = VStrength::PULL; }
+        |       yWEAK0                                  { $$ = VStrength::WEAK; }
         ;
 
-strengthSpecE:                  // IEEE: drive_strength + pullup_strength + pulldown_strength + charge_strength - plus empty
-                /* empty */                             { }
-        |       strengthSpec                            { }
+strength1<strength>:
+                ySUPPLY1                                { $$ = VStrength::SUPPLY; }
+        |       ySTRONG1                                { $$ = VStrength::STRONG; }
+        |       yPULL1                                  { $$ = VStrength::PULL; }
+        |       yWEAK1                                  { $$ = VStrength::WEAK; }
         ;
 
-strengthSpec:                   // IEEE: drive_strength + pullup_strength + pulldown_strength + charge_strength - plus empty
-                yP_PAR__STRENGTH strength ')'                   { }
-        |       yP_PAR__STRENGTH strength ',' strength ')'      { }
+driveStrengthE<nodep>:
+                /* empty */                             { $$ = nullptr; }
+        |       driveStrength                           { $$ = $1; }
+        ;
+
+
+driveStrength<nodep>:
+                yP_PAR__STRENGTH strength0 ',' strength1 ')' { $$ = new AstStrengthSpec{$1, $2, $4}; }
+        |       yP_PAR__STRENGTH strength1 ',' strength0 ')' { $$ = new AstStrengthSpec{$1, $4, $2}; }
+        |       yP_PAR__STRENGTH strength0 ',' yHIGHZ1 ')' { BBUNSUP($<fl>4, "Unsupported: highz strength"); }
+        |       yP_PAR__STRENGTH strength1 ',' yHIGHZ0 ')' { BBUNSUP($<fl>4, "Unsupported: highz strength"); }
+        |       yP_PAR__STRENGTH yHIGHZ0 ',' strength1 ')' { BBUNSUP($<fl>2, "Unsupported: highz strength"); }
+        |       yP_PAR__STRENGTH yHIGHZ1 ',' strength0 ')' { BBUNSUP($<fl>2, "Unsupported: highz strength"); }
         ;
 
 //************************************************
diff --git a/test_regress/driver.pl b/test_regress/driver.pl
index 5f33c65eb..720d44008 100755
--- a/test_regress/driver.pl
+++ b/test_regress/driver.pl
@@ -1856,7 +1856,7 @@ sub _make_main {
 
     if ($self->{savable}) {
         $fh->print("    const char* save_time_strp = contextp->commandArgsPlusMatch(\"save_time=\");\n");
-        $fh->print("    unsigned int save_time = !save_time_strp[0] ? 0 : atoi(save_time_strp+strlen(\"+save_time=\"));\n");
+        $fh->print("    unsigned int save_time = !save_time_strp[0] ? 0 : std::atoi(save_time_strp + std::strlen(\"+save_time=\"));\n");
         $fh->print("    const char* save_restore_strp = contextp->commandArgsPlusMatch(\"save_restore=\");\n");
         $fh->print("    unsigned int save_restore = !save_restore_strp[0] ? 0 : 1;\n");
     }
diff --git a/test_regress/t/TestCheck.h b/test_regress/t/TestCheck.h
index ac42dde3b..2f8cf2283 100644
--- a/test_regress/t/TestCheck.h
+++ b/test_regress/t/TestCheck.h
@@ -34,7 +34,7 @@ static const bool verbose = false;
 
 #define TEST_CHECK_EQ(got, exp) TEST_CHECK(got, exp, ((got) == (exp)));
 #define TEST_CHECK_NE(got, exp) TEST_CHECK(got, exp, ((got) != (exp)));
-#define TEST_CHECK_CSTR(got, exp) TEST_CHECK(got, exp, 0 == strcmp((got), (exp)));
+#define TEST_CHECK_CSTR(got, exp) TEST_CHECK(got, exp, 0 == std::strcmp((got), (exp)));
 
 #define TEST_CHECK_HEX_EQ(got, exp) \
     do { \
diff --git a/test_regress/t/TestSimulator.h b/test_regress/t/TestSimulator.h
index 6272887d8..c25304f6e 100644
--- a/test_regress/t/TestSimulator.h
+++ b/test_regress/t/TestSimulator.h
@@ -28,13 +28,13 @@ private:
 public:
     TestSimulator() {
         vpi_get_vlog_info(&m_info);
-        if (0 == strcmp(m_info.product, "Verilator")) {
+        if (0 == std::strcmp(m_info.product, "Verilator")) {
             m_simulators.verilator = true;
-        } else if (0 == strcmp(m_info.product, "Verilator")) {
+        } else if (0 == std::strcmp(m_info.product, "Verilator")) {
             m_simulators.icarus = true;
         } else if (0
                    == strncmp(m_info.product, "Chronologic Simulation VCS",
-                              strlen("Chronologic Simulation VCS"))) {
+                              std::strlen("Chronologic Simulation VCS"))) {
             m_simulators.vcs = true;
         } else {
             printf("%%Warning: %s:%d: Unknown simulator in TestSimulator.h: %s\n", __FILE__,
diff --git a/test_regress/t/t_EXAMPLE.v b/test_regress/t/t_EXAMPLE.v
index 0e3a9b428..236e0f85d 100644
--- a/test_regress/t/t_EXAMPLE.v
+++ b/test_regress/t/t_EXAMPLE.v
@@ -13,7 +13,7 @@
 // please note it here, otherwise:**
 //
 // This file ONLY is placed under the Creative Commons Public Domain, for
-// any use, without warranty, 2022 by ____YOUR_NAME_HERE____.
+// any use, without warranty, 2022 by Wilson Snyder.
 // SPDX-License-Identifier: CC0-1.0
 
 module t(/*AUTOARG*/
diff --git a/test_regress/t/t_class1.v b/test_regress/t/t_class1.v
index b584c5be6..c10125c51 100644
--- a/test_regress/t/t_class1.v
+++ b/test_regress/t/t_class1.v
@@ -12,14 +12,20 @@ class Cls;
 endclass : Cls
 
 module t (/*AUTOARG*/);
+   typedef Cls Cls2;
+
    initial begin
       Cls c;
+      Cls2 c2;
       if (c != null) $stop;
       if (c) $stop;
+      if (c2) $stop;
       $display("Display: null = \"%p\"", c);  // null
       c = new;
+      c2 = new;
       if (c == null) $stop;
       if (!c) $stop;
+      if (!c2) $stop;
       $display("Display: newed = \"%p\"", c);  // '{imembera:0, imemberb:0}
       c.imembera = 10;
       c.imemberb = 20;
diff --git a/test_regress/t/t_class_method_str_literal.pl b/test_regress/t/t_class_method_str_literal.pl
new file mode 100755
index 000000000..b46d46042
--- /dev/null
+++ b/test_regress/t/t_class_method_str_literal.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_class_method_str_literal.v b/test_regress/t/t_class_method_str_literal.v
new file mode 100644
index 000000000..3e5e9225d
--- /dev/null
+++ b/test_regress/t/t_class_method_str_literal.v
@@ -0,0 +1,28 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t;
+
+class T;
+    function automatic void print_str(input string a_string);
+        $display(a_string);
+    endfunction
+
+    static function automatic void static_print_str(input string a_string);
+        $display(a_string);
+    endfunction
+endclass
+
+
+initial begin
+    T t_c = new;
+    t_c.print_str("function though member");
+    t_c.static_print_str("static function through member");
+    T::static_print_str("static function through class");
+    $write("*-* All Finished *-*\n");
+    $finish;
+end
+endmodule
diff --git a/test_regress/t/t_dpi_arg_inout_type.cpp b/test_regress/t/t_dpi_arg_inout_type.cpp
index a5c346d8f..f5b109b39 100644
--- a/test_regress/t/t_dpi_arg_inout_type.cpp
+++ b/test_regress/t/t_dpi_arg_inout_type.cpp
@@ -168,10 +168,10 @@ void i_string(const char** x) {
     static int n = 0;
     printf("i_string %d\n", n);
     if (n++ % 2 == 0) {
-        if (strcmp(*x, "Hello") != 0) stop();
+        if (std::strcmp(*x, "Hello") != 0) stop();
         *x = "Good";
     } else {
-        if (strcmp(*x, "World") != 0) stop();
+        if (std::strcmp(*x, "World") != 0) stop();
         *x = "Bye";
     }
 }
@@ -296,10 +296,10 @@ void i_string_t(const char** x) {
     static int n = 0;
     printf("i_string_t %d\n", n);
     if (n++ % 2 == 0) {
-        if (strcmp(*x, "World") != 0) stop();
+        if (std::strcmp(*x, "World") != 0) stop();
         *x = "Bye";
     } else {
-        if (strcmp(*x, "Hello") != 0) stop();
+        if (std::strcmp(*x, "Hello") != 0) stop();
         *x = "Good";
     }
 }
@@ -962,10 +962,10 @@ void check_exports() {
     e_string(&x_string);
     if ((n % 2) == 0) {
         if (x_chandle) stop();
-        if (strcmp(x_string, "Hello") != 0) stop();
+        if (std::strcmp(x_string, "Hello") != 0) stop();
     } else {
         if (x_chandle) stop();
-        if (strcmp(x_string, "World") != 0) stop();
+        if (std::strcmp(x_string, "World") != 0) stop();
     }
 
     x_bit = n % 2;
@@ -1045,10 +1045,10 @@ void check_exports() {
     e_string_t(&x_string_t);
     if ((n % 2) == 0) {
         if (x_chandle_t != NULL) stop();
-        if (strcmp(x_string_t, "World") != 0) stop();
+        if (std::strcmp(x_string_t, "World") != 0) stop();
     } else {
         if (x_chandle_t != NULL) stop();
-        if (strcmp(x_string_t, "Hello") != 0) stop();
+        if (std::strcmp(x_string_t, "Hello") != 0) stop();
     }
 
     x_bit_t = n % 2;
diff --git a/test_regress/t/t_dpi_arg_input_type.cpp b/test_regress/t/t_dpi_arg_input_type.cpp
index 1593e1dfc..ee7f56d79 100644
--- a/test_regress/t/t_dpi_arg_input_type.cpp
+++ b/test_regress/t/t_dpi_arg_input_type.cpp
@@ -155,9 +155,9 @@ void i_string(const char* i) {
     static int n = 0;
     printf("i_string %d\n", n);
     if (n++ % 2 == 0) {
-        if (strcmp(i, "World") != 0) stop();
+        if (std::strcmp(i, "World") != 0) stop();
     } else {
-        if (strcmp(i, "Hello") != 0) stop();
+        if (std::strcmp(i, "Hello") != 0) stop();
     }
 }
 
@@ -266,9 +266,9 @@ void i_string_t(const char* i) {
     static int n = 0;
     printf("i_string_t %d\n", n);
     if (n++ % 2 == 0) {
-        if (strcmp(i, "World") != 0) stop();
+        if (std::strcmp(i, "World") != 0) stop();
     } else {
-        if (strcmp(i, "Hello") != 0) stop();
+        if (std::strcmp(i, "Hello") != 0) stop();
     }
 }
 
diff --git a/test_regress/t/t_dpi_arg_output_type.cpp b/test_regress/t/t_dpi_arg_output_type.cpp
index cf127ee6e..b8eda4a74 100644
--- a/test_regress/t/t_dpi_arg_output_type.cpp
+++ b/test_regress/t/t_dpi_arg_output_type.cpp
@@ -711,9 +711,9 @@ void check_exports() {
 
     e_string(&x_string);
     if ((n % 2) == 0) {
-        if (strcmp(x_string, "Hello") != 0) stop();
+        if (std::strcmp(x_string, "Hello") != 0) stop();
     } else {
-        if (strcmp(x_string, "World") != 0) stop();
+        if (std::strcmp(x_string, "World") != 0) stop();
     }
 
     e_bit(&x_bit);
@@ -772,9 +772,9 @@ void check_exports() {
 
     e_string_t(&x_string_t);
     if ((n % 2) == 0) {
-        if (strcmp(x_string_t, "Hello") != 0) stop();
+        if (std::strcmp(x_string_t, "Hello") != 0) stop();
     } else {
-        if (strcmp(x_string_t, "World") != 0) stop();
+        if (std::strcmp(x_string_t, "World") != 0) stop();
     }
 
     e_bit_t(&x_bit_t);
diff --git a/test_regress/t/t_dpi_export_c.cpp b/test_regress/t/t_dpi_export_c.cpp
index da9fee221..8b60a1c66 100644
--- a/test_regress/t/t_dpi_export_c.cpp
+++ b/test_regress/t/t_dpi_export_c.cpp
@@ -115,9 +115,10 @@ int dpix_run_tests() {
 
 #ifndef CADENCE  // Unimplemented; how hard is it?
     printf("svDpiVersion: %s\n", svDpiVersion());
-    CHECK_RESULT(
-        bool,
-        strcmp(svDpiVersion(), "1800-2005") == 0 || strcmp(svDpiVersion(), "P1800-2005") == 0, 1);
+    CHECK_RESULT(bool,
+                 std::strcmp(svDpiVersion(), "1800-2005") == 0
+                     || std::strcmp(svDpiVersion(), "P1800-2005") == 0,
+                 1);
 #endif
 
     CHECK_RESULT(int, dpix_int123(), 0x123);
diff --git a/test_regress/t/t_dpi_result_type.cpp b/test_regress/t/t_dpi_result_type.cpp
index a0d7b3cb5..bc8314a15 100644
--- a/test_regress/t/t_dpi_result_type.cpp
+++ b/test_regress/t/t_dpi_result_type.cpp
@@ -303,9 +303,9 @@ void check_exports() {
 #endif
     if (e_chandle()) stop();
     if ((n % 2) == 0) {
-        if (strcmp(e_string(), "Hello") != 0) stop();
+        if (std::strcmp(e_string(), "Hello") != 0) stop();
     } else {
-        if (strcmp(e_string(), "World") != 0) stop();
+        if (std::strcmp(e_string(), "World") != 0) stop();
     }
     if (e_bit() != (n % 2)) stop();
     if (e_logic() != !(n % 2)) stop();
@@ -327,9 +327,9 @@ void check_exports() {
 #endif
     if (e_chandle_t()) stop();
     if ((n % 2) == 0) {
-        if (strcmp(e_string_t(), "Hello") != 0) stop();
+        if (std::strcmp(e_string_t(), "Hello") != 0) stop();
     } else {
-        if (strcmp(e_string_t(), "World") != 0) stop();
+        if (std::strcmp(e_string_t(), "World") != 0) stop();
     }
     if (e_bit_t() != (n % 2)) stop();
     if (e_logic_t() != !(n % 2)) stop();
diff --git a/test_regress/t/t_dpi_string_c.cpp b/test_regress/t/t_dpi_string_c.cpp
index 05b001886..9216d9316 100644
--- a/test_regress/t/t_dpi_string_c.cpp
+++ b/test_regress/t/t_dpi_string_c.cpp
@@ -39,5 +39,5 @@ extern int dpii_string(const char* s);
 
 int dpii_string(const char* s) {
     printf("dpii_string: %s\n", s);
-    return strlen(s);
+    return std::strlen(s);
 }
diff --git a/test_regress/t/t_dpi_var.cpp b/test_regress/t/t_dpi_var.cpp
index f35647d41..5f9ee79f1 100644
--- a/test_regress/t/t_dpi_var.cpp
+++ b/test_regress/t/t_dpi_var.cpp
@@ -60,9 +60,9 @@ void mon_scope_name(const char* namep) {
 #ifdef TEST_VERBOSE
     VL_PRINTF("-     mon_scope_name('%s', \"%s\");\n", modp, namep);
 #endif
-    if (strcmp(namep, "t.sub"))
+    if (std::strcmp(namep, "t.sub"))
         vl_fatal(__FILE__, __LINE__, "", (std::string{"Unexp scope name "} + namep).c_str());
-    if (strcmp(modp, "t.sub"))
+    if (std::strcmp(modp, "t.sub"))
         vl_fatal(__FILE__, __LINE__, "", (std::string{"Unexp dpiscope name "} + modp).c_str());
 }
 
diff --git a/test_regress/t/t_flag_main.pl b/test_regress/t/t_flag_main.pl
index 381004460..57041562f 100755
--- a/test_regress/t/t_flag_main.pl
+++ b/test_regress/t/t_flag_main.pl
@@ -11,6 +11,9 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 scenarios(simulator => 1);
 
 compile(
+    verilator_flags => [# Custom as don't want -cc
+                        "-Mdir $Self->{obj_dir}",
+                        "--debug-check", ],
     verilator_flags2 => ['--exe --build --main'],
     verilator_make_cmake => 0,
     verilator_make_gmake => 0,
diff --git a/test_regress/t/t_flag_prefix.pl b/test_regress/t/t_flag_prefix.pl
new file mode 100755
index 000000000..adcce742d
--- /dev/null
+++ b/test_regress/t/t_flag_prefix.pl
@@ -0,0 +1,49 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Geza Lore. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+compile(
+    verilator_flags2 => ["--prefix t_flag_prefix", # should be overridden
+                         "--prefix Vprefix",
+                         "--exe", "--main", "--stats", "--build"],
+    verilator_make_cmake => 0,
+    verilator_make_gmake => 0,
+    make_main => 0,
+    );
+
+execute(
+    check_finished => 1,
+    executable => "$Self->{obj_dir}/Vprefix",
+    );
+
+sub check_files {
+    foreach my $path (glob("$Self->{obj_dir}/*")) {
+        my $filename = substr $path, ((length $Self->{obj_dir}) + 1);
+        next if ($filename =~ /^.*\.log$/);
+        if ($filename =~ /t_flag_prefix/) {
+            error("bad filename $filename");
+            next;
+        }
+        next if ($filename =~ /^(.*\.(o|a)|Vprefix)$/);
+        my $fh = IO::File->new("<$path") or error("$! $filenme");
+        while (defined(my $line = $fh->getline)) {
+            $line =~ s/--prefix V?t_flag_prefix//g;
+            $line =~ s/obj_vlt\/t_flag_prefix//g;
+            $line =~ s/t\/t_flag_prefix\.v//g;
+            error("bad line in $filename: $line") if $line =~ /t_flag_prefix/;
+        }
+    }
+}
+
+check_files();
+
+ok(1);
+1;
diff --git a/test_regress/t/t_flag_prefix.v b/test_regress/t/t_flag_prefix.v
new file mode 100755
index 000000000..00634520b
--- /dev/null
+++ b/test_regress/t/t_flag_prefix.v
@@ -0,0 +1,35 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Geza Lore.
+// SPDX-License-Identifier: CC0-1.0
+
+module t;
+   sub sub();
+endmodule
+
+module sub;
+   // no_inline_module, so it goes into separate file
+   /* verilator no_inline_module */
+
+   // Goes into const pool which is separate file
+   wire bit   [255:0] C = {32'h1111_1111,
+                           32'h2222_2222,
+                           32'h3333_3333,
+                           32'h4444_4444,
+                           32'h5555_5555,
+                           32'h6666_6666,
+                           32'h7777_7777,
+                           32'h8888_8888};
+
+   initial begin
+      // Note: Base index via $c to prevent optimization
+      $display("0x%32x", C[$c(0*32)+:32]);
+      $display("0x%32x", C[$c(2*32)+:32]);
+      $display("0x%32x", C[$c(4*32)+:32]);
+      $display("0x%32x", C[$c(6*32)+:32]);
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule
diff --git a/test_regress/t/t_mailbox.out b/test_regress/t/t_mailbox.out
index 5a7cc1581..4d5432212 100644
--- a/test_regress/t/t_mailbox.out
+++ b/test_regress/t/t_mailbox.out
@@ -1,4 +1,6 @@
 %Error: t/t_mailbox.v:20:4: Can't find typedef: 'mailbox'
-   20 |    mailbox m;
+   20 |    mailbox #(int) m;
       |    ^~~~~~~
-%Error: Exiting due to
+%Error: Internal Error: t/t_mailbox.v:20:14: ../V3LinkDot.cpp:#: Pin not under instance?
+   20 |    mailbox #(int) m;
+      |              ^~~
diff --git a/test_regress/t/t_mailbox.v b/test_regress/t/t_mailbox.v
index 21eadf323..06ea1f834 100644
--- a/test_regress/t/t_mailbox.v
+++ b/test_regress/t/t_mailbox.v
@@ -17,7 +17,7 @@
 //  endclass
 
 module t(/*AUTOARG*/);
-   mailbox m;
+   mailbox #(int) m;
    int     msg;
    int     out;
 
diff --git a/test_regress/t/t_mailbox_bad.out b/test_regress/t/t_mailbox_bad.out
new file mode 100644
index 000000000..4d5432212
--- /dev/null
+++ b/test_regress/t/t_mailbox_bad.out
@@ -0,0 +1,6 @@
+%Error: t/t_mailbox.v:20:4: Can't find typedef: 'mailbox'
+   20 |    mailbox #(int) m;
+      |    ^~~~~~~
+%Error: Internal Error: t/t_mailbox.v:20:14: ../V3LinkDot.cpp:#: Pin not under instance?
+   20 |    mailbox #(int) m;
+      |              ^~~
diff --git a/test_regress/t/t_mailbox_bad.pl b/test_regress/t/t_mailbox_bad.pl
new file mode 100755
index 000000000..8de551634
--- /dev/null
+++ b/test_regress/t/t_mailbox_bad.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+top_filename("t_mailbox.v");
+
+lint(
+    verilator_flags2 => ["--xml-only"],
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_mailbox_bad.v b/test_regress/t/t_mailbox_bad.v
new file mode 100644
index 000000000..a8bcb84fc
--- /dev/null
+++ b/test_regress/t/t_mailbox_bad.v
@@ -0,0 +1,17 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t(/*AUTOARG*/);
+   mailbox #(int) m;
+
+   initial begin
+      m = new(4);
+      if (m.bad_method() != 0) $stop;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule
diff --git a/test_regress/t/t_process.v b/test_regress/t/t_process.v
index f6ee27bac..0d495ab17 100644
--- a/test_regress/t/t_process.v
+++ b/test_regress/t/t_process.v
@@ -6,16 +6,16 @@
 
 // Methods defined by IEEE:
 //  class process;
-//     enum state { FINISHED, RUNNING, WAITING, SUSPENDED, KILLED };
+//     enum state { FINISHED, RUNNING, WAITING, SUSPENDED, KILLED };  // UVM uses KILLED, FINISHED
 //     static function process self();
 //     function state status();
 //     function void kill();
 //     task await();  // Warn as unsupported (no UVM library use)
 //     function void suspend();  // Warn as unsupported (no UVM library use)
 //     function void resume();  // Warn as unsupported (no UVM library use)
-//     function void srandom( int seed );  // Just ignore?
-//     function string get_randstate();  // Just ignore?
-//     function void set_randstate( string state );  // Just ignore?
+//     function void srandom( int seed );  // Operate on all proceses for now?
+//     function string get_randstate();  // Operate on all proceses for now?
+//     function void set_randstate( string state );  // Operate on all proceses for now?
 //   endclass
 
 module t(/*AUTOARG*/);
diff --git a/test_regress/t/t_process_bad.out b/test_regress/t/t_process_bad.out
new file mode 100644
index 000000000..a4ada3778
--- /dev/null
+++ b/test_regress/t/t_process_bad.out
@@ -0,0 +1,10 @@
+%Error: t/t_process.v:22:4: Can't find typedef: 'process'
+   22 |    process p;
+      |    ^~~~~~~
+%Error-UNSUPPORTED: t/t_process.v:26:20: Unsupported: 'process'
+   26 |       p = process::self();
+      |                    ^~~~
+                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
+%Error: Internal Error: t/t_process.v:26:11: ../V3LinkDot.cpp:#: Bad package link
+   26 |       p = process::self();
+      |           ^~~~~~~
diff --git a/test_regress/t/t_process_bad.pl b/test_regress/t/t_process_bad.pl
new file mode 100755
index 000000000..7be24ae56
--- /dev/null
+++ b/test_regress/t/t_process_bad.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+top_filename("t_process.v");
+
+lint(
+    verilator_flags2 => ["--xml-only"],
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_process_bad.v b/test_regress/t/t_process_bad.v
new file mode 100644
index 000000000..d32afb72b
--- /dev/null
+++ b/test_regress/t/t_process_bad.v
@@ -0,0 +1,20 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t(/*AUTOARG*/);
+   process p;
+
+   initial begin
+      if (p != null) $stop;
+      p = process::self();
+      if (p.bad_method() != 0) $stop;
+
+      p.bad_method_2();
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule
diff --git a/test_regress/t/t_sc_names.cpp b/test_regress/t/t_sc_names.cpp
index 6839252b0..6f73c4c1d 100644
--- a/test_regress/t/t_sc_names.cpp
+++ b/test_regress/t/t_sc_names.cpp
@@ -15,7 +15,7 @@ int sc_main(int argc, char* argv[]) {
 
     /* We expect to find clk in here. */
     for (int i = 0; i < ch.size(); ++i) {
-        if (!strcmp(ch[i]->basename(), "clk")) found = true;
+        if (!std::strcmp(ch[i]->basename(), "clk")) found = true;
     }
 
     if (found) {
diff --git a/test_regress/t/t_scope_map.cpp b/test_regress/t/t_scope_map.cpp
index 9136c8ee3..d9f554d8b 100644
--- a/test_regress/t/t_scope_map.cpp
+++ b/test_regress/t/t_scope_map.cpp
@@ -100,7 +100,7 @@ int main(int argc, char** argv, char** env) {
 #endif
 
             // Clear out the data
-            memset(varData, 0, (varBits + 7) / 8);
+            std::memset(varData, 0, (varBits + 7) / 8);
         }
     }
 
diff --git a/test_regress/t/t_semaphore.out b/test_regress/t/t_semaphore.out
index 21345fd35..76d60e04d 100644
--- a/test_regress/t/t_semaphore.out
+++ b/test_regress/t/t_semaphore.out
@@ -1,4 +1,7 @@
 %Error: t/t_semaphore.v:17:4: Can't find typedef: 'semaphore'
    17 |    semaphore s;
       |    ^~~~~~~~~
+%Error: t/t_semaphore.v:18:4: Can't find typedef: 'semaphore'
+   18 |    semaphore s2;
+      |    ^~~~~~~~~
 %Error: Exiting due to
diff --git a/test_regress/t/t_semaphore.v b/test_regress/t/t_semaphore.v
index 322a8541a..bc229ad75 100644
--- a/test_regress/t/t_semaphore.v
+++ b/test_regress/t/t_semaphore.v
@@ -13,8 +13,9 @@
 //  endclass
 
 module t(/*AUTOARG*/);
-   //From UVM:
+   // From UVM:
    semaphore s;
+   semaphore s2;
    int       msg;
 
    initial begin
@@ -30,6 +31,7 @@ module t(/*AUTOARG*/);
       s.put(2);
       if (s.try_get(2) <= 0) $stop;
 
+`ifndef VERILATOR
       fork
          begin
             #10;  // So later then get() starts below
@@ -42,6 +44,10 @@ module t(/*AUTOARG*/);
             s.get();
          end
       join
+`endif
+
+      s2 = new;
+      if (s2.try_get() != 0) $stop;
 
       $write("*-* All Finished *-*\n");
       $finish;
diff --git a/test_regress/t/t_semaphore_bad.out b/test_regress/t/t_semaphore_bad.out
new file mode 100644
index 000000000..76d60e04d
--- /dev/null
+++ b/test_regress/t/t_semaphore_bad.out
@@ -0,0 +1,7 @@
+%Error: t/t_semaphore.v:17:4: Can't find typedef: 'semaphore'
+   17 |    semaphore s;
+      |    ^~~~~~~~~
+%Error: t/t_semaphore.v:18:4: Can't find typedef: 'semaphore'
+   18 |    semaphore s2;
+      |    ^~~~~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_semaphore_bad.pl b/test_regress/t/t_semaphore_bad.pl
new file mode 100755
index 000000000..92483cce2
--- /dev/null
+++ b/test_regress/t/t_semaphore_bad.pl
@@ -0,0 +1,22 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+top_filename("t_semaphore.v");
+
+lint(
+    verilator_flags2 => ["--xml-only"],
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_semaphore_bad.v b/test_regress/t/t_semaphore_bad.v
new file mode 100644
index 000000000..68e6ee38b
--- /dev/null
+++ b/test_regress/t/t_semaphore_bad.v
@@ -0,0 +1,17 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+module t(/*AUTOARG*/);
+   semaphore s;
+
+   initial begin
+      s = new(4);
+      if (s.bad_method() != 0) $stop;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule
diff --git a/test_regress/t/t_strength_assignments.pl b/test_regress/t/t_strength_assignments.pl
new file mode 100755
index 000000000..f5e338520
--- /dev/null
+++ b/test_regress/t/t_strength_assignments.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Antmicro Ltd. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_strength_assignments.v b/test_regress/t/t_strength_assignments.v
new file mode 100644
index 000000000..8344adbdd
--- /dev/null
+++ b/test_regress/t/t_strength_assignments.v
@@ -0,0 +1,38 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/);
+   wire a;
+   assign (weak0, weak1) a = 1;
+   assign (weak0, supply1) a = 1;
+   assign (strong0, strong1) a = 0;
+
+   wire (weak0, weak1) b = 1;
+   assign (strong0, strong1) b = 0;
+
+   wire [1:0] c;
+   assign (weak0, supply1) c = '1;
+   assign (supply0, pull1) c = '1;
+   assign (strong0, strong1) c = '0;
+
+   supply0 d;
+   assign (strong0, strong1) d = 1;
+
+   wire (supply0, supply1) e = 'z;
+   assign (weak0, weak1) e = 1;
+
+   always begin
+      if (a && !b && c === '1 && !d && e) begin
+         $write("*-* All Finished *-*\n");
+         $finish;
+      end
+      else begin
+         $write("Error: a = %b, b = %b, c = %b, d = %b, e = %b ", a, b, c, d, e);
+         $write("expected: a = 1, b = 0, c = 11, d = 0, e = 1\n");
+         $stop;
+      end
+   end
+endmodule
diff --git a/test_regress/t/t_strength_bufif1.out b/test_regress/t/t_strength_bufif1.out
new file mode 100644
index 000000000..0ac300369
--- /dev/null
+++ b/test_regress/t/t_strength_bufif1.out
@@ -0,0 +1,5 @@
+%Error-UNSUPPORTED: t/t_strength_bufif1.v:9:11: Unsupported: Strength specifier on this gate type
+    9 |    bufif1 (strong0, strong1) (a, 1'b1, 1'b1);
+      |           ^
+                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
+%Error: Exiting due to
diff --git a/test_regress/t/t_strength_bufif1.pl b/test_regress/t/t_strength_bufif1.pl
new file mode 100755
index 000000000..35c0dfe5b
--- /dev/null
+++ b/test_regress/t/t_strength_bufif1.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Antmicro Ltd. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+lint(
+    fails => $Self->{vlt_all},
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_strength_bufif1.v b/test_regress/t/t_strength_bufif1.v
new file mode 100644
index 000000000..0a78b107c
--- /dev/null
+++ b/test_regress/t/t_strength_bufif1.v
@@ -0,0 +1,17 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/);
+   wire a;
+   bufif1 (strong0, strong1) (a, 1'b1, 1'b1);
+
+   always begin
+      if (a) begin
+         $write("*-* All Finished *-*\n");
+         $finish;
+      end
+   end
+endmodule
diff --git a/test_regress/t/t_strength_highz.out b/test_regress/t/t_strength_highz.out
new file mode 100644
index 000000000..06f32f6e9
--- /dev/null
+++ b/test_regress/t/t_strength_highz.out
@@ -0,0 +1,14 @@
+%Error-UNSUPPORTED: t/t_strength_highz.v:8:17: Unsupported: highz strength
+    8 |    wire (weak0, highz1) a = 1;
+      |                 ^~~~~~
+                    ... For error description see https://verilator.org/warn/UNSUPPORTED?v=latest
+%Error-UNSUPPORTED: t/t_strength_highz.v:9:19: Unsupported: highz strength
+    9 |    wire (strong1, highz0) b = 0;
+      |                   ^~~~~~
+%Error-UNSUPPORTED: t/t_strength_highz.v:10:10: Unsupported: highz strength
+   10 |    wire (highz0, pull1) c = 0;
+      |          ^~~~~~
+%Error-UNSUPPORTED: t/t_strength_highz.v:11:10: Unsupported: highz strength
+   11 |    wire (highz1, supply0) d = 1;
+      |          ^~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_strength_highz.pl b/test_regress/t/t_strength_highz.pl
new file mode 100755
index 000000000..48bf31461
--- /dev/null
+++ b/test_regress/t/t_strength_highz.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt => 1);
+
+lint(
+    fails => $Self->{vlt_all},
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_strength_highz.v b/test_regress/t/t_strength_highz.v
new file mode 100644
index 000000000..340723aba
--- /dev/null
+++ b/test_regress/t/t_strength_highz.v
@@ -0,0 +1,19 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/);
+   wire (weak0, highz1) a = 1;
+   wire (strong1, highz0) b = 0;
+   wire (highz0, pull1) c = 0;
+   wire (highz1, supply0) d = 1;
+
+   always begin
+      if (a === 1'bz && b === 1'bz && c === 1'bz && d === 1'bz) begin
+         $write("*-* All Finished *-*\n");
+         $finish;
+      end
+   end
+endmodule
diff --git a/test_regress/t/t_strength_strong1_strong1_bad.out b/test_regress/t/t_strength_strong1_strong1_bad.out
new file mode 100644
index 000000000..b1e299714
--- /dev/null
+++ b/test_regress/t/t_strength_strong1_strong1_bad.out
@@ -0,0 +1,4 @@
+%Error: t/t_strength_strong1_strong1_bad.v:8:19: syntax error, unexpected strong1
+    8 |    wire (strong1, strong1) a = 1;
+      |                   ^~~~~~~
+%Error: Exiting due to
diff --git a/test_regress/t/t_strength_strong1_strong1_bad.pl b/test_regress/t/t_strength_strong1_strong1_bad.pl
new file mode 100755
index 000000000..19ba90d40
--- /dev/null
+++ b/test_regress/t/t_strength_strong1_strong1_bad.pl
@@ -0,0 +1,19 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Antmicro Ltd. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(linter => 1);
+
+lint(
+    fails => 1,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_strength_strong1_strong1_bad.v b/test_regress/t/t_strength_strong1_strong1_bad.v
new file mode 100644
index 000000000..ab84216cc
--- /dev/null
+++ b/test_regress/t/t_strength_strong1_strong1_bad.v
@@ -0,0 +1,13 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/);
+   wire (strong1, strong1) a = 1;
+   initial begin
+      $stop;
+   end
+
+endmodule
diff --git a/test_regress/t/t_var_sc_bv.cpp b/test_regress/t/t_var_sc_bv.cpp
new file mode 100644
index 000000000..d8324bf2f
--- /dev/null
+++ b/test_regress/t/t_var_sc_bv.cpp
@@ -0,0 +1,220 @@
+// -*- mode: C++; c-file-style: "cc-mode" -*-
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2022 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+#include VM_PREFIX_INCLUDE
+
+VM_PREFIX* tb = nullptr;
+bool pass = true;
+
+double sc_time_stamp() { return 0; }
+
+void compare_signals(const sc_signal<sc_bv<256>>& ls, const sc_signal<sc_bv<256>>& rs) {
+    if (ls.read() != rs.read()) {
+        pass &= false;
+        VL_PRINTF("%%Error: Data missmatch in signals %s and %s\n", ls.name(), rs.name());
+    }
+}
+
+void compareWls(int obits, WDataInP const lwp, WDataInP const rwp) {
+    const int words = VL_WORDS_I(obits);
+    bool same = true;
+
+    for (int i = 0; (i < (words - 1)); ++i) {
+        if (lwp[i] != rwp[i]) { same = false; }
+    }
+    if ((lwp[words - 1] & VL_MASK_E(obits)) != (rwp[words - 1] & VL_MASK_E(obits))) {
+        same = false;
+    }
+
+    if (!same) {
+        pass &= false;
+        VL_PRINTF("%%Error: There is a difference in VlWide variable %d bits wide\n", obits);
+    }
+}
+
+// old macro which is correct but has MT issue with range
+#define VL_ASSIGN_SBW_MT_ISSUE(obits, svar, rwp) \
+    { \
+        sc_biguint<(obits)> _butemp; \
+        for (int i = 0; i < VL_WORDS_I(obits); ++i) { \
+            int msb = ((i + 1) * VL_IDATASIZE) - 1; \
+            msb = (msb >= (obits)) ? ((obits)-1) : msb; \
+            _butemp.range(msb, i* VL_IDATASIZE) = (rwp)[i]; \
+        } \
+        (svar).write(_butemp); \
+    }
+
+#ifdef SYSTEMC_VERSION
+int sc_main(int, char**)
+#else
+int main()
+#endif
+{
+    Verilated::debug(0);
+    tb = new VM_PREFIX("tb");
+
+    VlWide<8> /*255:0*/ input_var;
+    VlWide<8> /*255:0*/ out_var;
+
+    // msb is always set to F not to be false positive on checking equality
+    input_var.m_storage[0] = 0xF2341234;
+    input_var.m_storage[1] = 0xFEADBEEF;
+    input_var.m_storage[2] = 0xF5A5A5A5;
+    input_var.m_storage[3] = 0xF1B2C3D4;
+    input_var.m_storage[4] = 0xFFFFFFFF;
+    input_var.m_storage[5] = 0xFAAABBBB;
+    input_var.m_storage[6] = 0xF000AAAA;
+    input_var.m_storage[7] = 0xF0101010;
+
+#ifdef SYSTEMC_VERSION
+    // clang-format off
+    sc_signal<sc_bv<256>> SC_NAMED(i_29_s), SC_NAMED(i_29_old_s), SC_NAMED(o_29_s), SC_NAMED(o_29_old_s),
+                          SC_NAMED(i_30_s), SC_NAMED(i_30_old_s), SC_NAMED(o_30_s), SC_NAMED(o_30_old_s),
+                          SC_NAMED(i_31_s), SC_NAMED(i_31_old_s), SC_NAMED(o_31_s), SC_NAMED(o_31_old_s),
+                          SC_NAMED(i_32_s), SC_NAMED(i_32_old_s), SC_NAMED(o_32_s), SC_NAMED(o_32_old_s),
+                          SC_NAMED(i_59_s), SC_NAMED(i_59_old_s), SC_NAMED(o_59_s), SC_NAMED(o_59_old_s),
+                          SC_NAMED(i_60_s), SC_NAMED(i_60_old_s), SC_NAMED(o_60_s), SC_NAMED(o_60_old_s),
+                          SC_NAMED(i_62_s), SC_NAMED(i_62_old_s), SC_NAMED(o_62_s), SC_NAMED(o_62_old_s),
+                          SC_NAMED(i_64_s), SC_NAMED(i_64_old_s), SC_NAMED(o_64_s), SC_NAMED(o_64_old_s),
+                          SC_NAMED(i_119_s), SC_NAMED(i_119_old_s), SC_NAMED(o_119_s), SC_NAMED(o_119_old_s),
+                          SC_NAMED(i_120_s), SC_NAMED(i_120_old_s), SC_NAMED(o_120_s), SC_NAMED(o_120_old_s),
+                          SC_NAMED(i_121_s), SC_NAMED(i_121_old_s), SC_NAMED(o_121_s), SC_NAMED(o_121_old_s),
+                          SC_NAMED(i_127_s), SC_NAMED(i_127_old_s), SC_NAMED(o_127_s), SC_NAMED(o_127_old_s),
+                          SC_NAMED(i_128_s), SC_NAMED(i_128_old_s), SC_NAMED(o_128_s), SC_NAMED(o_128_old_s),
+                          SC_NAMED(i_255_s), SC_NAMED(i_255_old_s), SC_NAMED(o_255_s), SC_NAMED(o_255_old_s),
+                          SC_NAMED(i_256_s), SC_NAMED(i_256_old_s), SC_NAMED(o_256_s), SC_NAMED(o_256_old_s);
+
+
+    tb->i_29(i_29_s); tb->i_29_old(i_29_old_s); tb->o_29(o_29_s); tb->o_29_old(o_29_old_s);
+    tb->i_30(i_30_s); tb->i_30_old(i_30_old_s); tb->o_30(o_30_s); tb->o_30_old(o_30_old_s);
+    tb->i_31(i_31_s); tb->i_31_old(i_31_old_s); tb->o_31(o_31_s); tb->o_31_old(o_31_old_s);
+    tb->i_32(i_32_s); tb->i_32_old(i_32_old_s); tb->o_32(o_32_s); tb->o_32_old(o_32_old_s);
+    tb->i_59(i_59_s); tb->i_59_old(i_59_old_s); tb->o_59(o_59_s); tb->o_59_old(o_59_old_s);
+    tb->i_60(i_60_s); tb->i_60_old(i_60_old_s); tb->o_60(o_60_s); tb->o_60_old(o_60_old_s);
+    tb->i_62(i_62_s); tb->i_62_old(i_62_old_s); tb->o_62(o_62_s); tb->o_62_old(o_62_old_s);
+    tb->i_64(i_64_s); tb->i_64_old(i_64_old_s); tb->o_64(o_64_s); tb->o_64_old(o_64_old_s);
+    tb->i_119(i_119_s); tb->i_119_old(i_119_old_s); tb->o_119(o_119_s); tb->o_119_old(o_119_old_s);
+    tb->i_120(i_120_s); tb->i_120_old(i_120_old_s); tb->o_120(o_120_s); tb->o_120_old(o_120_old_s);
+    tb->i_121(i_121_s); tb->i_121_old(i_121_old_s); tb->o_121(o_121_s); tb->o_121_old(o_121_old_s);
+    tb->i_127(i_127_s); tb->i_127_old(i_127_old_s); tb->o_127(o_127_s); tb->o_127_old(o_127_old_s);
+    tb->i_128(i_128_s); tb->i_128_old(i_128_old_s); tb->o_128(o_128_s); tb->o_128_old(o_128_old_s);
+    tb->i_255(i_255_s); tb->i_255_old(i_255_old_s); tb->o_255(o_255_s); tb->o_255_old(o_255_old_s);
+    tb->i_256(i_256_s); tb->i_256_old(i_256_old_s); tb->o_256(o_256_s); tb->o_256_old(o_256_old_s);
+
+    // clang-format on
+
+#endif
+
+// clang-format off
+#ifdef SYSTEMC_VERSION
+    sc_start(1, SC_NS);
+#else
+    tb->eval();
+#endif
+    // This testcase is testing multi-thread safe VL_ASSIGN_SBW and VL_ASSIGN_WSB macros.
+    // Testbench is assigning different number of bits from VlWide input_var variable to different inputs.
+    // Values around multiple of 30 (i.e. BITS_PER_DIGIT defined in SystemC sc_nbdefs.h) are tested with the special care, since
+    // it is the value by which the data_ptr of sc_biguint underlying data type is increased by (and not expected 32, as width of uint32_t).
+    // Correctness of the output is compared against the 'old' macro, which is correct but has multi-threaded issue since it's using range function.
+    // Second part is testing VL_ASSIGN_WSB in a reverse way, it is reading signals from the previous test,
+    // and comparing the output with (fraction) of VlWide input_var variable.
+
+    // clang-format on
+    VL_ASSIGN_SBW(29, i_29_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(29, i_29_old_s, input_var);
+    VL_ASSIGN_SBW(30, i_30_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(30, i_30_old_s, input_var);
+    VL_ASSIGN_SBW(31, i_31_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(31, i_31_old_s, input_var);
+    VL_ASSIGN_SBW(32, i_32_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(32, i_32_old_s, input_var);
+    VL_ASSIGN_SBW(59, i_59_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(59, i_59_old_s, input_var);
+    VL_ASSIGN_SBW(60, i_60_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(60, i_60_old_s, input_var);
+    VL_ASSIGN_SBW(62, i_62_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(62, i_62_old_s, input_var);
+    VL_ASSIGN_SBW(64, i_64_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(64, i_64_old_s, input_var);
+    VL_ASSIGN_SBW(119, i_119_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(119, i_119_old_s, input_var);
+    VL_ASSIGN_SBW(120, i_120_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(120, i_120_old_s, input_var);
+    VL_ASSIGN_SBW(121, i_121_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(121, i_121_old_s, input_var);
+    VL_ASSIGN_SBW(127, i_127_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(127, i_127_old_s, input_var);
+    VL_ASSIGN_SBW(128, i_128_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(128, i_128_old_s, input_var);
+    VL_ASSIGN_SBW(255, i_255_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(255, i_255_old_s, input_var);
+    VL_ASSIGN_SBW(256, i_256_s, input_var);
+    VL_ASSIGN_SBW_MT_ISSUE(256, i_256_old_s, input_var);
+
+#ifdef SYSTEMC_VERSION
+    sc_start(1, SC_NS);
+#else
+    tb->eval();
+#endif
+    compare_signals(o_29_s, o_29_old_s);
+    compare_signals(o_30_s, o_30_old_s);
+    compare_signals(o_31_s, o_31_old_s);
+    compare_signals(o_32_s, o_32_old_s);
+    compare_signals(o_59_s, o_59_old_s);
+    compare_signals(o_60_s, o_60_old_s);
+    compare_signals(o_62_s, o_62_old_s);
+    compare_signals(o_64_s, o_64_old_s);
+    compare_signals(o_119_s, o_119_old_s);
+    compare_signals(o_120_s, o_120_old_s);
+    compare_signals(o_121_s, o_121_old_s);
+    compare_signals(o_127_s, o_127_old_s);
+    compare_signals(o_128_s, o_128_old_s);
+    compare_signals(o_255_s, o_255_old_s);
+    compare_signals(o_256_s, o_256_old_s);
+
+    ////////////////////////////////
+
+    VL_ASSIGN_WSB(29, out_var, o_29_s);
+    compareWls(29, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(30, out_var, o_30_s);
+    compareWls(30, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(31, out_var, o_31_s);
+    compareWls(31, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(32, out_var, o_32_s);
+    compareWls(32, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(59, out_var, o_59_s);
+    compareWls(59, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(60, out_var, o_60_s);
+    compareWls(60, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(62, out_var, o_62_s);
+    compareWls(62, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(64, out_var, o_64_s);
+    compareWls(64, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(119, out_var, o_119_s);
+    compareWls(119, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(120, out_var, o_120_s);
+    compareWls(120, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(121, out_var, o_121_s);
+    compareWls(121, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(127, out_var, o_127_s);
+    compareWls(127, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(128, out_var, o_128_s);
+    compareWls(128, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(255, out_var, o_255_s);
+    compareWls(255, input_var.data(), out_var.data());
+    VL_ASSIGN_WSB(256, out_var, o_256_s);
+    compareWls(256, input_var.data(), out_var.data());
+
+    tb->final();
+    VL_DO_DANGLING(delete tb, tb);
+
+    if (pass) {
+        VL_PRINTF("*-* All Finished *-*\n");
+    } else {
+        vl_fatal(__FILE__, __LINE__, "top", "Unexpected results from test\n");
+    }
+    return 0;
+}
diff --git a/test_regress/t/t_var_sc_bv.pl b/test_regress/t/t_var_sc_bv.pl
new file mode 100755
index 000000000..0091e49f0
--- /dev/null
+++ b/test_regress/t/t_var_sc_bv.pl
@@ -0,0 +1,24 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2003-2009 by Wilson Snyder. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(vlt_all => 1);
+
+compile(
+    make_top_shell => 0,
+    make_main => 0,
+    verilator_flags2 => ["--exe $Self->{t_dir}/t_var_sc_bv.cpp --sc -fno-inline"],
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_var_sc_bv.v b/test_regress/t/t_var_sc_bv.v
new file mode 100644
index 000000000..d3164ee09
--- /dev/null
+++ b/test_regress/t/t_var_sc_bv.v
@@ -0,0 +1,246 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2008 by Lane Brooks.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/
+   // Outputs
+   o_29,o_29_old,
+   o_30,o_30_old,
+   o_31,o_31_old,
+   o_32,o_32_old,
+   o_59,o_59_old,
+   o_60,o_60_old,
+   o_62,o_62_old,
+   o_64,o_64_old,
+   o_119,o_119_old,
+   o_120,o_120_old,
+   o_121,o_121_old,
+   o_127,o_127_old,
+   o_128,o_128_old,
+   o_255,o_255_old,
+   o_256,o_256_old,
+   // Inputs
+   i_29,i_29_old,
+   i_30,i_30_old,
+   i_31,i_31_old,
+   i_32,i_32_old,
+   i_59,i_59_old,
+   i_60,i_60_old,
+   i_62,i_62_old,
+   i_64,i_64_old,
+   i_119,i_119_old,
+   i_120,i_120_old,
+   i_121,i_121_old,
+   i_127,i_127_old,
+   i_128,i_128_old,
+   i_255,i_255_old,
+   i_256,i_256_old
+   );
+   input [255:0]        i_29;
+   output wire [255:0]  o_29;
+   input [255:0]        i_29_old;
+   output wire [255:0]  o_29_old;
+   input [255:0]        i_30;
+   output wire [255:0]  o_30;
+   input [255:0]        i_30_old;
+   output wire [255:0]  o_30_old;
+   input [255:0]        i_31;
+   output wire [255:0]  o_31;
+   input [255:0]        i_31_old;
+   output wire [255:0]  o_31_old;
+   input [255:0]        i_32;
+   output wire [255:0]  o_32;
+   input [255:0]        i_32_old;
+   output wire [255:0]  o_32_old;
+   input [255:0]        i_59;
+   output wire [255:0]  o_59;
+   input [255:0]        i_59_old;
+   output wire [255:0]  o_59_old;
+   input [255:0]        i_60;
+   output wire [255:0]  o_60;
+   input [255:0]        i_60_old;
+   output wire [255:0]  o_60_old;
+   input [255:0]        i_62;
+   output wire [255:0]  o_62;
+   input [255:0]        i_62_old;
+   output wire [255:0]  o_62_old;
+   input [255:0]        i_64;
+   output wire [255:0]  o_64;
+   input [255:0]        i_64_old;
+   output wire [255:0]  o_64_old;
+   input [255:0]       i_119;
+   output wire [255:0] o_119;
+   input [255:0]       i_119_old;
+   output wire [255:0] o_119_old;
+   input [255:0]       i_120;
+   output wire [255:0] o_120;
+   input [255:0]       i_120_old;
+   output wire [255:0] o_120_old;
+   input [255:0]       i_121;
+   output wire [255:0] o_121;
+   input [255:0]       i_121_old;
+   output wire [255:0] o_121_old;
+   input [255:0]       i_127;
+   output wire [255:0] o_127;
+   input [255:0]       i_127_old;
+   output wire [255:0] o_127_old;
+   input [255:0]       i_128;
+   output wire [255:0] o_128;
+   input [255:0]       i_128_old;
+   output wire [255:0] o_128_old;
+   input [255:0]       i_255;
+   output wire [255:0] o_255;
+   input [255:0]       i_255_old;
+   output wire [255:0] o_255_old;
+   input [255:0]       i_256;
+   output wire [255:0] o_256;
+   input [255:0]       i_256_old;
+   output wire [255:0] o_256_old;
+
+   sub sub (.*);
+endmodule
+
+module sub (/*AUTOARG*/
+   // Outputs
+   o_29,o_29_old,
+   o_30,o_30_old,
+   o_31,o_31_old,
+   o_32,o_32_old,
+   o_59,o_59_old,
+   o_60,o_60_old,
+   o_62,o_62_old,
+   o_64,o_64_old,
+   o_119,o_119_old,
+   o_120,o_120_old,
+   o_121,o_121_old,
+   o_127,o_127_old,
+   o_128,o_128_old,
+   o_255,o_255_old,
+   o_256,o_256_old,
+   // Inputs
+   i_29,i_29_old,
+   i_30,i_30_old,
+   i_31,i_31_old,
+   i_32,i_32_old,
+   i_59,i_59_old,
+   i_60,i_60_old,
+   i_62,i_62_old,
+   i_64,i_64_old,
+   i_119,i_119_old,
+   i_120,i_120_old,
+   i_121,i_121_old,
+   i_127,i_127_old,
+   i_128,i_128_old,
+   i_255,i_255_old,
+   i_256,i_256_old
+   );
+
+   input [255:0]        i_29;
+   output wire [255:0]  o_29;
+   input [255:0]        i_29_old;
+   output wire [255:0]  o_29_old;
+   input [255:0]        i_30;
+   output wire [255:0]  o_30;
+   input [255:0]        i_30_old;
+   output wire [255:0]  o_30_old;
+   input [255:0]        i_31;
+   output wire [255:0]  o_31;
+   input [255:0]        i_31_old;
+   output wire [255:0]  o_31_old;
+   input [255:0]        i_32;
+   output wire [255:0]  o_32;
+   input [255:0]        i_32_old;
+   output wire [255:0]  o_32_old;
+   input [255:0]        i_59;
+   output wire [255:0]  o_59;
+   input [255:0]        i_59_old;
+   output wire [255:0]  o_59_old;
+   input [255:0]        i_60;
+   output wire [255:0]  o_60;
+   input [255:0]        i_60_old;
+   output wire [255:0]  o_60_old;
+   input [255:0]        i_62;
+   output wire [255:0]  o_62;
+   input [255:0]        i_62_old;
+   output wire [255:0]  o_62_old;
+   input [255:0]        i_64;
+   output wire [255:0]  o_64;
+   input [255:0]        i_64_old;
+   output wire [255:0]  o_64_old;
+   input [255:0]       i_119;
+   output wire [255:0] o_119;
+   input [255:0]       i_119_old;
+   output wire [255:0] o_119_old;
+   input [255:0]       i_120;
+   output wire [255:0] o_120;
+   input [255:0]       i_120_old;
+   output wire [255:0] o_120_old;
+   input [255:0]       i_121;
+   output wire [255:0] o_121;
+   input [255:0]       i_121_old;
+   output wire [255:0] o_121_old;
+   input [255:0]       i_127;
+   output wire [255:0] o_127;
+   input [255:0]       i_127_old;
+   output wire [255:0] o_127_old;
+   input [255:0]       i_128;
+   output wire [255:0] o_128;
+   input [255:0]       i_128_old;
+   output wire [255:0] o_128_old;
+   input [255:0]       i_255;
+   output wire [255:0] o_255;
+   input [255:0]       i_255_old;
+   output wire [255:0] o_255_old;
+   input [255:0]       i_256;
+   output wire [255:0] o_256;
+   input [255:0]       i_256_old;
+   output wire [255:0] o_256_old;
+
+   assign o_29 = i_29;
+   assign o_29_old = i_29_old;
+
+   assign o_30 = i_30;
+   assign o_30_old = i_30_old;
+
+   assign o_31 = i_31;
+   assign o_31_old = i_31_old;
+
+   assign o_32 = i_32;
+   assign o_32_old = i_32_old;
+
+   assign o_59 = i_59;
+   assign o_59_old = i_59_old;
+
+   assign o_60 = i_60;
+   assign o_60_old = i_60_old;
+
+   assign o_62 = i_62;
+   assign o_62_old = i_62_old;
+
+   assign o_64 = i_64;
+   assign o_64_old = i_64_old;
+
+   assign o_119 = i_119;
+   assign o_119_old = i_119_old;
+
+   assign o_120 = i_120;
+   assign o_120_old = i_120_old;
+
+   assign o_121 = i_121;
+   assign o_121_old = i_121_old;
+
+   assign o_127 = i_127;
+   assign o_127_old = i_127_old;
+
+   assign o_128 = i_128;
+   assign o_128_old = i_128_old;
+
+   assign o_255 = i_255;
+   assign o_255_old = i_255_old;
+
+   assign o_256 = i_256;
+   assign o_256_old = i_256_old;
+
+endmodule
diff --git a/test_regress/t/t_vpi_get.cpp b/test_regress/t/t_vpi_get.cpp
index fdd93ee01..898664841 100644
--- a/test_regress/t/t_vpi_get.cpp
+++ b/test_regress/t/t_vpi_get.cpp
@@ -71,7 +71,7 @@
     }
 
 #define CHECK_RESULT_CSTR(got, exp) \
-    if (strcmp((got), (exp))) { \
+    if (std::strcmp((got), (exp))) { \
         printf("%%Error: %s:%d: GOT = '%s'   EXP = '%s'\n", FILENM, __LINE__, \
                (got) ? (got) : "<null>", (exp) ? (exp) : "<null>"); \
         return __LINE__; \
diff --git a/test_regress/t/t_vpi_module.cpp b/test_regress/t/t_vpi_module.cpp
index 754cc2660..1c2de048c 100644
--- a/test_regress/t/t_vpi_module.cpp
+++ b/test_regress/t/t_vpi_module.cpp
@@ -61,7 +61,7 @@
     }
 
 #define CHECK_RESULT_CSTR(got, exp) \
-    if (strcmp((got), (exp))) { \
+    if (std::strcmp((got), (exp))) { \
         printf("%%Error: %s:%d: GOT = '%s'   EXP = '%s'\n", FILENM, __LINE__, \
                (got) ? (got) : "<null>", (exp) ? (exp) : "<null>"); \
         return __LINE__; \
@@ -100,7 +100,7 @@ int mon_check() {
     CHECK_RESULT_NZ(t_name);
 
     // Icarus reports the top most module as "top"
-    if (strcmp(t_name, "top") == 0) {
+    if (std::strcmp(t_name, "top") == 0) {
         it = vpi_iterate(vpiModule, topmod);
         CHECK_RESULT_NZ(it);
         CHECK_RESULT(vpi_get(vpiType, it), vpiModule);
@@ -129,7 +129,7 @@ int mon_check() {
     CHECK_RESULT_NZ(mod3);
 
     const char* mod_c_name = vpi_get_str(vpiName, mod3);
-    if (strcmp(mod_c_name, "mod_b") == 0) {
+    if (std::strcmp(mod_c_name, "mod_b") == 0) {
         // Full visibility in other simulators, skip mod_b
         TestVpiHandle mod4 = vpi_scan(it3);
         CHECK_RESULT_NZ(mod4);
diff --git a/test_regress/t/t_vpi_param.cpp b/test_regress/t/t_vpi_param.cpp
index 51415a38b..dcc4a7fb9 100644
--- a/test_regress/t/t_vpi_param.cpp
+++ b/test_regress/t/t_vpi_param.cpp
@@ -71,7 +71,7 @@
     }
 
 #define CHECK_RESULT_CSTR(got, exp) \
-    if (strcmp((got), (exp))) { \
+    if (std::strcmp((got), (exp))) { \
         printf("%%Error: %s:%d: GOT = '%s'   EXP = '%s'\n", FILENM, __LINE__, \
                (got) ? (got) : "<null>", (exp) ? (exp) : "<null>"); \
         return __LINE__; \
diff --git a/test_regress/t/t_vpi_unimpl.cpp b/test_regress/t/t_vpi_unimpl.cpp
index 549d66e1e..e91515a6e 100644
--- a/test_regress/t/t_vpi_unimpl.cpp
+++ b/test_regress/t/t_vpi_unimpl.cpp
@@ -66,7 +66,7 @@ unsigned int callback_count = 0;
     }
 
 #define CHECK_RESULT_CSTR(got, exp) \
-    if (strcmp((got), (exp))) { \
+    if (std::strcmp((got), (exp))) { \
         printf("%%Error: %s:%d: GOT = '%s'   EXP = '%s'\n", FILENM, __LINE__, \
                (got) ? (got) : "<null>", (exp) ? (exp) : "<null>"); \
         return __LINE__; \
diff --git a/test_regress/t/t_vpi_var.cpp b/test_regress/t/t_vpi_var.cpp
index b8186c281..1c5c76f50 100644
--- a/test_regress/t/t_vpi_var.cpp
+++ b/test_regress/t/t_vpi_var.cpp
@@ -90,7 +90,7 @@ bool verbose = false;
     }
 
 #define CHECK_RESULT_CSTR(got, exp) \
-    if (strcmp((got), (exp))) { \
+    if (std::strcmp((got), (exp))) { \
         printf("%%Error: %s:%d: GOT = '%s'   EXP = '%s'\n", FILENM, __LINE__, \
                ((got) != NULL) ? (got) : "<null>", ((exp) != NULL) ? (exp) : "<null>"); \
         return __LINE__; \
@@ -117,7 +117,7 @@ int _mon_check_mcd() {
     }
 
     status = vpi_mcd_printf(mcd, (PLI_BYTE8*)"hello %s", "vpi_mcd_printf");
-    CHECK_RESULT(status, strlen("hello vpi_mcd_printf"));
+    CHECK_RESULT(status, std::strlen("hello vpi_mcd_printf"));
 
     status = vpi_mcd_printf(0, (PLI_BYTE8*)"empty");
     CHECK_RESULT(status, 0);
@@ -634,7 +634,7 @@ int _mon_check_vlog_info() {
     CHECK_RESULT_Z(vlog_info.argv[4]);
     if (TestSimulator::is_verilator()) {
         CHECK_RESULT_CSTR(vlog_info.product, "Verilator");
-        CHECK_RESULT(strlen(vlog_info.version) > 0, 1);
+        CHECK_RESULT(std::strlen(vlog_info.version) > 0, 1);
     }
     return 0;
 }
diff --git a/test_regress/t/t_weak_nor_strong_assign.pl b/test_regress/t/t_weak_nor_strong_assign.pl
new file mode 100755
index 000000000..f5e338520
--- /dev/null
+++ b/test_regress/t/t_weak_nor_strong_assign.pl
@@ -0,0 +1,21 @@
+#!/usr/bin/env perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2022 by Antmicro Ltd. This program is free software; you
+# can redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+# SPDX-License-Identifier: LGPL-3.0-only OR Artistic-2.0
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    check_finished => 1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_weak_nor_strong_assign.v b/test_regress/t/t_weak_nor_strong_assign.v
new file mode 100644
index 000000000..a3811ca71
--- /dev/null
+++ b/test_regress/t/t_weak_nor_strong_assign.v
@@ -0,0 +1,18 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2022 by Antmicro Ltd.
+// SPDX-License-Identifier: CC0-1.0
+
+module t (/*AUTOARG*/);
+   wire a;
+   nor (pull0, weak1) n1(a, 0, 0);
+   assign (strong0, weak1) a = 0;
+
+   always begin
+      if (!a) begin
+         $write("*-* All Finished *-*\n");
+         $finish;
+      end
+   end
+endmodule