Fix range check in V3SplitVar to be consistent with #2507 (#2511)

* test:Add more tests for checking split_var for unpacked array.

* Fix range calculation of SliceSel and change to UASSERT_OBJ because the range check is done in V3Width beforehand.

src/V3SplitVar.cpp

@@ -275,10 +275,6 @@ public:
         return m_index;
     }
     AstNode* context() const { return m_contextp; }
-    std::pair<int, int> range() const {
-        UASSERT_OBJ(VN_IS(m_nodep, SliceSel), m_nodep, "not slice sel");
-        return std::make_pair(m_msb, m_lsb);
-    }
     bool lvalue() const { return m_lvalue; }
     bool ftask() const { return m_ftask; }
     bool operator<(const UnpackRef& other) const {
@@ -584,16 +580,16 @@ class SplitUnpackedVarVisitor : public AstNVisitor, public SplitVarImpl {
         if (AstVarRef* refp = isTargetVref(nodep->fromp())) {
             AstUnpackArrayDType* dtypep
                 = VN_CAST(refp->varp()->dtypep()->skipRefp(), UnpackArrayDType);
-            if (dtypep->lsb() <= nodep->declRange().lo()
-                && nodep->declRange().hi() <= dtypep->msb()) {  // Range is ok
-                UINFO(4, "add " << nodep << " for " << refp->varp()->prettyName() << "\n");
-                m_refs.tryAdd(m_contextp, refp, nodep, nodep->declRange().hi(),
-                              nodep->declRange().lo(), m_inFTask);
-            } else {
-                nodep->v3warn(SPLITVAR, refp->prettyNameQ()
-                                            << notSplitMsg << "index if out of range.\n");
-                m_refs.remove(refp->varp());
-            }
+            // declRange() of AstSliceSel is shifted by dtypep->declRange().lo() in V3WidthSel.cpp
+            // restore the original decl range here.
+            const VNumRange selRange{nodep->declRange().hi() + dtypep->declRange().lo(),
+                                     nodep->declRange().lo() + dtypep->declRange().lo(),
+                                     nodep->declRange().littleEndian()};
+            UASSERT_OBJ(dtypep->lsb() <= selRange.lo() && selRange.hi() <= dtypep->msb(), nodep,
+                        "Range check for AstSliceSel must have been finished in V3Width.cpp");
+            UINFO(4, "add " << nodep << " for " << refp->varp()->prettyName() << "\n");
+            m_refs.tryAdd(m_contextp, refp, nodep, nodep->declRange().hi(),
+                          nodep->declRange().lo(), m_inFTask);
         } else {
             iterateChildren(nodep);
         }

test_regress/t/t_split_var_0.pl

@@ -23,6 +23,6 @@ execute(
     );
 
 file_grep($Self->{stats}, qr/SplitVar,\s+Split packed variables\s+(\d+)/i, 13);
-file_grep($Self->{stats}, qr/SplitVar,\s+Split unpacked arrays\s+(\d+)/i, 23);
+file_grep($Self->{stats}, qr/SplitVar,\s+Split unpacked arrays\s+(\d+)/i, 27);
 ok(1);
 1;

test_regress/t/t_split_var_0.v

@@ -381,6 +381,39 @@ module through #(parameter WIDTH = 8)
 
 endmodule
 
+module delay (input wire clk);
+   logic unpack_sig0 [10:16] /*verilator split_var*/;
+   logic unpack_sig1 [13:16] /*verilator split_var*/;
+   logic unpack_sig2 [16:10] /*verilator split_var*/;
+   logic unpack_sig3 [16:13] /*verilator split_var*/;
+
+   always @(posedge clk) begin
+      if (c <= 5) begin
+         unpack_sig0[13] <= 1'b1;
+         unpack_sig1[13] <= 1'b1;
+         unpack_sig0 [13+1:16] <= unpack_sig0[13:16-1];
+         unpack_sig1 [13+1:16] <= unpack_sig1[13:16-1];
+         unpack_sig2[13] <= 1'b1;
+         unpack_sig3[13] <= 1'b1;
+         unpack_sig2 [16:13+1] <= unpack_sig2[16-1:13];
+         unpack_sig3 [16:13+1] <= unpack_sig3[16-1:13];
+      end
+   end
+
+   int c = 0;
+   always @(posedge clk) begin
+      c <= c + 1;
+      if (c >= 4) begin
+         if (!unpack_sig0[16] || !unpack_sig1[16]) $stop;
+         if (!unpack_sig2[16] || !unpack_sig3[16]) $stop;
+      end else begin
+         if (unpack_sig0[16] || unpack_sig1[16]) $stop;
+         if (unpack_sig2[16] || unpack_sig3[16]) $stop;
+      end
+   end
+endmodule
+
+
 module t(/*AUTOARG*/ clk);
    input clk;
    localparam DEPTH = 3;
@@ -403,6 +436,7 @@ module t(/*AUTOARG*/ clk);
    barshift_1d_packed_struct                     shifter7(.in(in), .out(out[7]), .shift(shift));
    barshift_bitslice            #(.DEPTH(DEPTH)) shifter8(.in(in), .out(out[8]), .shift(shift));
    through                      #(.WIDTH(WIDTH)) though0 (.in(out[8]), .out(through_tmp));
+   delay                                         delay0(.clk(clk));
    var_decl_with_init i_var_decl_with_init();
    t_array_rev i_t_array_rev(clk);
 

test_regress/t/t_split_var_2_trace.pl

@@ -25,7 +25,7 @@ execute(
 
 vcd_identical("$Self->{obj_dir}/simx.vcd", $Self->{golden_filename});
 file_grep($Self->{stats}, qr/SplitVar,\s+Split packed variables\s+(\d+)/i, 12);
-file_grep($Self->{stats}, qr/SplitVar,\s+Split unpacked arrays\s+(\d+)/i, 23);
+file_grep($Self->{stats}, qr/SplitVar,\s+Split unpacked arrays\s+(\d+)/i, 27);
 
 ok(1);
 1;