diff --git a/include/verilated.cpp b/include/verilated.cpp
index 627ca744e..c583e5668 100644
--- a/include/verilated.cpp
+++ b/include/verilated.cpp
@@ -285,6 +285,7 @@ IData VL_RANDOM_I(int obits) VL_MT_SAFE {
 QData VL_RANDOM_Q(int obits) VL_MT_SAFE {
     return vl_rand64() & VL_MASK_Q(obits);
 }
+// VL_RANDOM_W currently unused as $random always 32 bits
 WDataOutP VL_RANDOM_W(int obits, WDataOutP outwp) VL_MT_SAFE {
     for (int i=0; i<VL_WORDS_I(obits); ++i) {
         if (i<(VL_WORDS_I(obits)-1)) {
diff --git a/include/verilated.h b/include/verilated.h
index a8d969b8c..0004e244a 100644
--- a/include/verilated.h
+++ b/include/verilated.h
@@ -318,8 +318,8 @@ public:  // But internals only - called from VerilatedModule's
         if (VL_LIKELY(funcnum < scopep->m_funcnumMax)) {
             // m_callbacksp must be declared, as Max'es are > 0
             return scopep->m_callbacksp[funcnum];
-        } else {
-            return scopep->exportFindError(funcnum);
+        } else {  // LCOV_EXCL_LINE
+            return scopep->exportFindError(funcnum);  // LCOV_EXCL_LINE
         }
     }
 };
diff --git a/nodist/code_coverage b/nodist/code_coverage
index 7b46ae17c..86180a972 100755
--- a/nodist/code_coverage
+++ b/nodist/code_coverage
@@ -53,6 +53,7 @@ sub test {
     if ($Opt_Stage <= 1) {
         print "Stage 1: make examples (with coverage on)\n";
         run("make examples");
+        run("make test_regress");
     }
 
     my $cc_dir = "nodist/obj_dir/coverage";
@@ -68,7 +69,7 @@ sub test {
         }
         foreach my $dir (sort keys %dirs) {
             (my $outname = $dir) =~ s![^a-zA-Z0-9]+!_!g;
-            run("cd $cc_dir/info ; lcov -c -d ../../../$dir -o app_test_${outname}.info");
+            run("cd $cc_dir/info ; lcov -c -d ../../../../$dir -o app_test_${outname}.info");
         }
     }
     
@@ -145,7 +146,7 @@ sub clone_sources {
                 chomp $line;
                 if ($line !~ m!// LCOV_EXCL_LINE!
                     && $line =~ /$Exclude_Line_Regexp/) {
-                    $line .= "  //code_coverage: // LCOV_EXCL_LINE\n";
+                    $line .= "  //code_coverage: // LCOV_EXCL_LINE";
                     $excluded_lines++;
                     #print "$infile:$lineno: $line";
                 } else {
@@ -164,9 +165,11 @@ sub cleanup_abs_paths {
     my $fh = IO::File->new("<$infile") or die "%Error: $! $infile,";
     my @lines;
     while (defined(my $line = $fh->getline)) {
-        if ($line =~ m!^SF:/!) {
+        if ($line =~ m!^SF:!) {
             $line =~ s!$ENV{VERILATOR_ROOT}/!!;
             $line =~ s!$cc_dir/!!;
+            $line =~ s!obj_dbg/verilog.y$!verilog.y!;
+            #print "Remaining SF: ",$line;
         }
         push @lines, $line;
     }
diff --git a/src/V3ActiveTop.cpp b/src/V3ActiveTop.cpp
index de9da5e24..f567bb4e6 100644
--- a/src/V3ActiveTop.cpp
+++ b/src/V3ActiveTop.cpp
@@ -101,7 +101,7 @@ private:
             // Move the active's contents to the other active
             UINFO(4,"   merge active "<<sensesp<<" into "<<wantp<<endl);
             if (nodep->sensesStorep()) {
-                if (sensesp != nodep->sensesStorep()) {
+                if (VL_UNCOVERABLE(sensesp != nodep->sensesStorep())) {
                     nodep->v3fatalSrc("sensesStore should have been deleted earlier if different");
                 }
                 sensesp->unlinkFrBack();
diff --git a/src/V3Broken.cpp b/src/V3Broken.cpp
index f5ce7c0c7..fcec7e9e7 100644
--- a/src/V3Broken.cpp
+++ b/src/V3Broken.cpp
@@ -60,7 +60,7 @@ public:
         // Called by operator delete on any node - only if VL_LEAK_CHECKS
         if (debug()>=9) cout<<"-nodeDel:  "<<cvtToHex(nodep)<<endl;
         NodeMap::iterator iter = s_nodes.find(nodep);
-        if (iter==s_nodes.end() || !(iter->second & FLAG_ALLOCATED)) {
+        if (VL_UNCOVERABLE(iter==s_nodes.end() || !(iter->second & FLAG_ALLOCATED))) {
             reinterpret_cast<const AstNode*>(nodep)
                 ->v3fatalSrc("Deleting AstNode object that was never tracked or already deleted");
         }
@@ -74,7 +74,7 @@ public:
         // Called by operator new on any node - only if VL_LEAK_CHECKS
         if (debug()>=9) cout<<"-nodeNew:  "<<cvtToHex(nodep)<<endl;
         NodeMap::iterator iter = s_nodes.find(nodep);
-        if (iter !=s_nodes.end() && (iter->second & FLAG_ALLOCATED)) {
+        if (VL_UNCOVERABLE(iter !=s_nodes.end() && (iter->second & FLAG_ALLOCATED))) {
             nodep->v3fatalSrc("Newing AstNode object that is already allocated");
         }
         if (iter == s_nodes.end()) {
@@ -96,17 +96,17 @@ public:
         if (!linkable) return;  // save some time, else the map will get huge!
 #endif
         NodeMap::iterator iter = s_nodes.find(nodep);
-        if (iter == s_nodes.end()) {
+        if (VL_UNCOVERABLE(iter == s_nodes.end())) {
 #ifdef VL_LEAK_CHECKS
             nodep->v3fatalSrc("AstNode is in tree, but not allocated");
 #endif
         } else {
-            if (!(iter->second & FLAG_ALLOCATED)) {
+            if (VL_UNCOVERABLE(!(iter->second & FLAG_ALLOCATED))) {
 #ifdef VL_LEAK_CHECKS
                 nodep->v3fatalSrc("AstNode is in tree, but not allocated");
 #endif
             }
-            if (iter->second & FLAG_IN_TREE) {
+            if (VL_UNCOVERABLE(iter->second & FLAG_IN_TREE)) {
                 nodep->v3fatalSrc("AstNode is already in tree at another location");
             }
         }
@@ -230,34 +230,35 @@ public:
 class BrokenCheckVisitor : public AstNVisitor {
 private:
     void checkWidthMin(const AstNode* nodep) {
-        if (nodep->width() != nodep->widthMin()
-            && v3Global.widthMinUsage()==VWidthMinUsage::MATCHES_WIDTH) {
+        if (VL_UNCOVERABLE(nodep->width() != nodep->widthMin()
+                           && v3Global.widthMinUsage()==VWidthMinUsage::MATCHES_WIDTH)) {
             nodep->v3fatalSrc("Width != WidthMin");
         }
     }
     void processAndIterate(AstNode* nodep) {
         BrokenTable::setUnder(nodep, true);
-        if (const char* whyp=nodep->broken()) {
+        const char* whyp = nodep->broken();
+        if (VL_UNCOVERABLE(whyp)) {
             nodep->v3fatalSrc("Broken link in node (or something without maybePointedTo): "<<whyp);
         }
         if (nodep->dtypep()) {
-            if (!nodep->dtypep()->brokeExists()) {
+            if (VL_UNCOVERABLE(!nodep->dtypep()->brokeExists())) {
                 nodep->v3fatalSrc("Broken link in node->dtypep() to "
                                   <<cvtToHex(nodep->dtypep()));
-            } else if (!VN_IS(nodep->dtypep(), NodeDType)) {
+            } else if (VL_UNCOVERABLE(!VN_IS(nodep->dtypep(), NodeDType))) {
                 nodep->v3fatalSrc("Non-dtype link in node->dtypep() to "
                                   <<cvtToHex(nodep->dtypep()));
             }
         }
         if (v3Global.assertDTypesResolved()) {
             if (nodep->hasDType()) {
-                if (!nodep->dtypep()) nodep->v3fatalSrc(
+                if (VL_UNCOVERABLE(!nodep->dtypep())) nodep->v3fatalSrc(
                     "No dtype on node with hasDType(): "<<nodep->prettyTypeName());
             } else {
-                if (nodep->dtypep()) nodep->v3fatalSrc(
+                if (VL_UNCOVERABLE(nodep->dtypep())) nodep->v3fatalSrc(
                     "DType on node without hasDType(): "<<nodep->prettyTypeName());
             }
-            if (nodep->getChildDTypep()) nodep->v3fatalSrc(
+            if (VL_UNCOVERABLE(nodep->getChildDTypep())) nodep->v3fatalSrc(
                 "childDTypep() non-null on node after should have removed");
             if (const AstNodeDType* dnodep = VN_CAST(nodep, NodeDType)) checkWidthMin(dnodep);
         }
@@ -267,10 +268,10 @@ private:
     }
     virtual void visit(AstNodeAssign* nodep) {
         processAndIterate(nodep);
-        if (v3Global.assertDTypesResolved()
-            && nodep->brokeLhsMustBeLvalue()
-            && VN_IS(nodep->lhsp(), NodeVarRef)
-            && !VN_CAST(nodep->lhsp(), NodeVarRef)->lvalue()) {
+        if (VL_UNCOVERABLE(v3Global.assertDTypesResolved()
+                           && nodep->brokeLhsMustBeLvalue()
+                           && VN_IS(nodep->lhsp(), NodeVarRef)
+                           && !VN_CAST(nodep->lhsp(), NodeVarRef)->lvalue())) {
             nodep->v3fatalSrc("Assignment LHS is not an lvalue");
         }
     }
@@ -291,9 +292,9 @@ public:
 void V3Broken::brokenAll(AstNetlist* nodep) {
     //UINFO(9,__FUNCTION__<<": "<<endl);
     static bool inBroken = false;
-    if (inBroken) {
+    if (VL_UNCOVERABLE(inBroken)) {
         // A error called by broken can recurse back into broken; avoid this
-        UINFO(1,"Broken called under broken, skipping recursion.\n");
+        UINFO(1,"Broken called under broken, skipping recursion.\n");  // LCOV_EXCL_LINE
     } else {
         inBroken = true;
         BrokenTable::prepForTree();
diff --git a/src/V3ParseGrammar.cpp b/src/V3ParseGrammar.cpp
index 7e5cebf67..fbe43d095 100644
--- a/src/V3ParseGrammar.cpp
+++ b/src/V3ParseGrammar.cpp
@@ -109,7 +109,7 @@ AstNodeDType* V3ParseGrammar::createArray(AstNodeDType* basep,
             if (prevp) nrangep->unlinkFrBack();
             AstRange* rangep = VN_CAST(nrangep, Range);
             if (!rangep) {
-                if (!VN_IS(nrangep, UnsizedRange)) {
+                if (VL_UNCOVERABLE(!VN_IS(nrangep, UnsizedRange))) {
                     nrangep->v3fatalSrc("Expected range or unsized range");
                 }
                 arrayp = new AstUnsizedArrayDType
diff --git a/src/V3Table.cpp b/src/V3Table.cpp
index 210939638..4204dfa47 100644
--- a/src/V3Table.cpp
+++ b/src/V3Table.cpp
@@ -219,7 +219,7 @@ private:
             nodeap->bodysp()->unlinkFrBackWithNext()->deleteTree();
             nodeap->addStmtp(stmtsp);
             if (debug()>=6) nodeap->dumpTree(cout, "  table_new: ");
-        } else {
+        } else {  // LCOV_EXCL_LINE
             nodep->v3fatalSrc("Creating table under unknown node type");
         }
 
@@ -316,7 +316,7 @@ private:
 
             // Simulate
             simvis.mainTableEmulate(nodep);
-            if (!simvis.optimizable()) {
+            if (VL_UNCOVERABLE(!simvis.optimizable())) {
                 simvis.whyNotNodep()->v3fatalSrc("Optimizable cleared, even though earlier test run said not: "
                                                  <<simvis.whyNotMessage());
             }
@@ -348,8 +348,9 @@ private:
             }
 
             {   // Set changed table
-                if (inValue != inValueNextInitArray++)
+                if (VL_UNCOVERABLE(inValue != inValueNextInitArray++)) {
                     nodep->v3fatalSrc("InitArray requires us to have the values in inValue order");
+                }
                 AstNode* setp = new AstConst(nodep->fileline(), outputChgMask);
                 VN_CAST(chgVscp->varp()->valuep(), InitArray)->addValuep(setp);
             }
diff --git a/src/V3WidthSel.cpp b/src/V3WidthSel.cpp
index b0f1da711..92c85693a 100644
--- a/src/V3WidthSel.cpp
+++ b/src/V3WidthSel.cpp
@@ -227,9 +227,11 @@ private:
                     subp = newSubNeg(subp, fromRange.lo());
                 }
             }
-            if (!fromRange.elements() || (adtypep->width() % fromRange.elements())!=0)
+            if (VL_UNCOVERABLE(!fromRange.elements()
+                               || (adtypep->width() % fromRange.elements())!=0)) {
                 adtypep->v3fatalSrc("Array extraction with width miscomputed "
                                     <<adtypep->width()<<"/"<<fromRange.elements());
+            }
             int elwidth = adtypep->width() / fromRange.elements();
             AstSel* newp
                 = new AstSel(nodep->fileline(),
@@ -316,9 +318,11 @@ private:
         else if (AstPackArrayDType* adtypep = VN_CAST(ddtypep, PackArrayDType)) {
             // SELEXTRACT(array, msb, lsb) -> SEL(array,
             //             lsb*width-of-subindex, width-of-subindex*(msb-lsb))
-            if (!fromRange.elements() || (adtypep->width() % fromRange.elements())!=0)
+            if (VL_UNCOVERABLE(!fromRange.elements()
+                               || (adtypep->width() % fromRange.elements())!=0)) {
                 adtypep->v3fatalSrc("Array extraction with width miscomputed "
                                     <<adtypep->width()<<"/"<<fromRange.elements());
+            }
             if (fromRange.littleEndian()) {
                 // Below code assumes big bit endian; just works out if we swap
                 int x = msb; msb = lsb; lsb = x;
@@ -478,7 +482,7 @@ private:
 
     //--------------------
     // Default
-    virtual void visit(AstNode* nodep) {
+    virtual void visit(AstNode* nodep) {  // LCOV_EXCL_LINE
         // See notes above; we never iterate
         nodep->v3fatalSrc("Shouldn't iterate in V3WidthSel");
     }
diff --git a/src/VlcTest.h b/src/VlcTest.h
index 4196eb6bb..e3a60a0f3 100644
--- a/src/VlcTest.h
+++ b/src/VlcTest.h
@@ -76,9 +76,9 @@ public:
         cout<<"  Covered,     Rank,  RankPts,  Filename"<<endl;
     }
     void dump(bool bucketsToo) {
-        if (testrun() || computrons()!=0.0) {
-            cout<<"  "<<std::setw(8)<<std::setfill('0')<<testrun()
-                <<",  "<<std::setw(7)<<std::setfill(' ')<<computrons()<<",";
+        if (testrun() || computrons()!=0.0) {  // currently unused // LCOV_EXCL_LINE
+            cout<<"  "<<std::setw(8)<<std::setfill('0')<<testrun()  // LCOV_EXCL_LINE
+                <<",  "<<std::setw(7)<<std::setfill(' ')<<computrons()<<",";  // LCOV_EXCL_LINE
         }
         cout<<"  "<<std::setw(7)<<std::setfill(' ')<<bucketsCovered()
             <<",  "<<std::setw(7)<<std::setfill(' ')<<rank()
diff --git a/test_regress/t/t_flag_debugi9.pl b/test_regress/t/t_flag_debugi9.pl
index d854713e8..bb7e70e7c 100755
--- a/test_regress/t/t_flag_debugi9.pl
+++ b/test_regress/t/t_flag_debugi9.pl
@@ -10,7 +10,7 @@ if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); di
 scenarios(vlt_all => 1);
 
 compile(
-    v_flags2 => ["--debugi 9"],
+    v_flags2 => ["--debug --debugi 9"],
     tee => 0,
     verilator_make_gcc => 0,
     make_top_shell => 0,
diff --git a/test_regress/t/t_flag_debugi9.v b/test_regress/t/t_flag_debugi9.v
index 6b8661775..5d61f1f0d 100644
--- a/test_regress/t/t_flag_debugi9.v
+++ b/test_regress/t/t_flag_debugi9.v
@@ -3,7 +3,18 @@
 // This file ONLY is placed into the Public Domain, for any use,
 // without warranty, 2008 by Wilson Snyder.
 
-module t;
+module t (/*AUTOARG*/
+   // Outputs
+   o,
+   // Inputs
+   i
+   );
+
+   // Need some logic to get mtask debug fully covered
+   input i;
+   output wire o;
+   assign o = i;
+
    initial begin
       $write("*-* All Finished *-*\n");
       $finish;
diff --git a/test_regress/t/t_stop_bad.out b/test_regress/t/t_stop_bad.out
new file mode 100644
index 000000000..a5b0b94b3
--- /dev/null
+++ b/test_regress/t/t_stop_bad.out
@@ -0,0 +1,3 @@
+Intentional stop
+%Error: t/t_stop_bad.v:9: Verilog $stop
+Aborting...
diff --git a/test_regress/t/t_stop_bad.pl b/test_regress/t/t_stop_bad.pl
new file mode 100755
index 000000000..477a847d8
--- /dev/null
+++ b/test_regress/t/t_stop_bad.pl
@@ -0,0 +1,23 @@
+#!/usr/bin/perl
+if (!$::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.
+
+scenarios(simulator => 1);
+
+compile(
+    );
+
+execute(
+    fails => 1,
+    check_finished => 0,
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+
+1;
diff --git a/test_regress/t/t_stop_bad.v b/test_regress/t/t_stop_bad.v
new file mode 100644
index 000000000..950a2d00f
--- /dev/null
+++ b/test_regress/t/t_stop_bad.v
@@ -0,0 +1,11 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2019 by Wilson Snyder.
+
+module t;
+   initial begin
+      $write("Intentional stop\n");
+      $stop;
+   end
+endmodule
diff --git a/test_regress/t/t_sys_system.v b/test_regress/t/t_sys_system.v
index eda684c94..612797f7c 100644
--- a/test_regress/t/t_sys_system.v
+++ b/test_regress/t/t_sys_system.v
@@ -22,6 +22,8 @@ module t;
       if (i!==0) $stop;
       i = $system("exit 10");
       if (i!==10) $stop;
+      i = $system("exit     20"); // Wide
+      if (i!==20) $stop;
 `endif
 
       $write("*-* All Finished *-*\n");
diff --git a/test_regress/t/t_vlcov_debugi.pl b/test_regress/t/t_vlcov_debugi.pl
new file mode 100755
index 000000000..a310de3ab
--- /dev/null
+++ b/test_regress/t/t_vlcov_debugi.pl
@@ -0,0 +1,26 @@
+#!/usr/bin/perl
+if (!$::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.
+
+scenarios(dist => 1);
+
+foreach my $basename ("t_vlcov_data_a.dat",
+                      "t_vlcov_data_b.dat",
+                      "t_vlcov_data_c.dat",
+                      "t_vlcov_data_d.dat",
+    ) {
+    run(cmd => ["../bin/verilator_coverage",
+                "t/${basename}",
+                "--debugi 9",
+        ],
+        tee => $Self->{verbose},
+        );
+}
+
+ok(1);
+1;
diff --git a/test_regress/t/t_vlcov_nfound_bad.out b/test_regress/t/t_vlcov_nfound_bad.out
new file mode 100644
index 000000000..e9884e58a
--- /dev/null
+++ b/test_regress/t/t_vlcov_nfound_bad.out
@@ -0,0 +1,2 @@
+%Error: Can't read t/t_NOT_FOUND
+%Error: Command Failed
diff --git a/test_regress/t/t_vlcov_nfound_bad.pl b/test_regress/t/t_vlcov_nfound_bad.pl
new file mode 100755
index 000000000..9b7a627db
--- /dev/null
+++ b/test_regress/t/t_vlcov_nfound_bad.pl
@@ -0,0 +1,20 @@
+#!/usr/bin/perl
+if (!$::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.
+
+scenarios(dist => 1);
+
+run(fails => 1,
+    cmd => ["../bin/verilator_coverage",
+            "t/t_NOT_FOUND",],
+    logfile => $Self->{run_log_filename},
+    expect_filename => $Self->{golden_filename},
+    );
+
+ok(1);
+1;