Support ++/-- on dotted member variables.

Changes

@@ -22,6 +22,7 @@ Verilator 5.009 devel
 * Support method calls without parenthesis (#4034). [Ryszard Rozak, Antmicro Ltd]
 * Support complicated IEEE 'for' assignments.
 * Support $fopen as an expression.
+* Support ++/-- on dotted member variables.
 * Change range order warning from LITENDIAN to ASCRANGE (#4010). [Iztok Jeras]
 * Change ZERODLY to a warning.
 * Fix random internal crashes (#666). [Dag Lem]

src/V3LinkInc.cpp

@@ -240,11 +240,12 @@ private:
             return;
         }
 
-        const AstNodeVarRef* varrefp = nullptr;
-        if (m_unsupportedHere || !(varrefp = VN_CAST(nodep->rhsp(), VarRef))) {
+        if (m_unsupportedHere) {
             nodep->v3warn(E_UNSUPPORTED, "Unsupported: Incrementation in this context.");
             return;
         }
+        AstNodeExpr* const readp = nodep->rhsp();
+        AstNodeExpr* const writep = nodep->thsp();
 
         AstConst* const constp = VN_AS(nodep->lhsp(), Const);
         UASSERT_OBJ(nodep, constp, "Expecting CONST");
@@ -254,8 +255,9 @@ private:
         // Prepare a temporary variable
         FileLine* const fl = backp->fileline();
         const string name = string{"__Vincrement"} + cvtToStr(++m_modIncrementsNum);
-        AstVar* const varp = new AstVar{fl, VVarType::BLOCKTEMP, name, VFlagChildDType{},
-                                        varrefp->varp()->subDTypep()->cloneTree(true)};
+        AstVar* const varp = new AstVar{
+            fl, VVarType::BLOCKTEMP, name, VFlagChildDType{},
+            new AstRefDType{fl, AstRefDType::FlagTypeOfExpr{}, readp->cloneTree(true)}};
         if (m_ftaskp) varp->funcLocal(true);
 
         // Declare the variable
@@ -264,30 +266,29 @@ private:
         // Define what operation will we be doing
         AstNodeExpr* operp;
         if (VN_IS(nodep, PostSub) || VN_IS(nodep, PreSub)) {
-            operp = new AstSub{fl, new AstVarRef{fl, varrefp->varp(), VAccess::READ}, newconstp};
+            operp = new AstSub{fl, readp->cloneTree(true), newconstp};
         } else {
-            operp = new AstAdd{fl, new AstVarRef{fl, varrefp->varp(), VAccess::READ}, newconstp};
+            operp = new AstAdd{fl, readp->cloneTree(true), newconstp};
         }
 
         if (VN_IS(nodep, PreAdd) || VN_IS(nodep, PreSub)) {
             // PreAdd/PreSub operations
             // Immediately after declaration - increment it by one
-            varp->addNextHere(new AstAssign{fl, new AstVarRef{fl, varrefp->varp(), VAccess::WRITE},
+            varp->addNextHere(new AstAssign{fl, writep->cloneTree(true),
                                             new AstVarRef{fl, varp, VAccess::READ}});
             // Immediately after incrementing - assign it to the original variable
             varp->addNextHere(new AstAssign{fl, new AstVarRef{fl, varp, VAccess::WRITE}, operp});
         } else {
             // PostAdd/PostSub operations
             // assign the original variable to the temporary one
-            varp->addNextHere(
-                new AstAssign{fl, new AstVarRef{fl, varrefp->varp(), VAccess::WRITE}, operp});
+            varp->addNextHere(new AstAssign{fl, writep->cloneTree(true), operp});
             // Increment the original variable by one
             varp->addNextHere(new AstAssign{fl, new AstVarRef{fl, varp, VAccess::WRITE},
-                                            new AstVarRef{fl, varrefp->varp(), VAccess::READ}});
+                                            readp->cloneTree(true)});
         }
 
         // Replace the node with the temporary
-        nodep->replaceWith(new AstVarRef{varrefp->fileline(), varp, VAccess::READ});
+        nodep->replaceWith(new AstVarRef{readp->fileline(), varp, VAccess::READ});
         VL_DO_DANGLING(nodep->deleteTree(), nodep);
     }
     void visit(AstPreAdd* nodep) override { prepost_visit(nodep); }

test_regress/t/t_class_inc.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 2023 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;

test_regress/t/t_class_inc.v

@@ -0,0 +1,37 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed under the Creative Commons Public Domain, for
+// any use, without warranty, 2023 by Wilson Snyder.
+// SPDX-License-Identifier: CC0-1.0
+
+class Base #(type T = integer);
+   T m_count;
+
+   function void test1();
+      if (this.m_count != 0) $stop;
+      if (this.m_count++ != 0) $stop;
+      if (this.m_count != 1) $stop;
+      if (m_count++ != 1) $stop;
+      if (this.m_count != 2) $stop;
+   endfunction
+endclass
+
+class Cls #(type T = integer) extends Base #(T);
+endclass
+
+module t;
+   Cls #(int) c;
+
+   initial begin
+      c = new;
+      c.test1();
+
+      c.m_count = 0;
+      if (c.m_count != 0) $stop;
+      if (c.m_count++ != 0) $stop;
+      if (c.m_count != 1) $stop;
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+endmodule

test_regress/t/t_increment_bad.out

@@ -17,9 +17,6 @@
 %Error-UNSUPPORTED: t/t_increment_bad.v:27:29: Unsupported: Incrementation in this context.
    27 |       pos = (a > 0) ? a++ : --b;
       |                             ^~
-%Error-UNSUPPORTED: t/t_increment_bad.v:29:24: Unsupported: Incrementation in this context.
-   29 |       pos = array[0][0]++;
-      |                        ^~
 %Error-UNSUPPORTED: t/t_increment_bad.v:32:37: Unsupported: Incrementation in this context.
    32 |    assert property (@(posedge clk) a++ >= 0);
       |                                     ^~

test_regress/t/t_math_real.v

@@ -138,6 +138,16 @@ module t (/*AUTOARG*/
       r = real'(96'shf0000000_00000000_00000000);
       if (r != -4951760157141521099596496896.0) $stop;
 
+      r = 1.5;
+      if (r++ != 1.5) $stop;
+      if (r != 2.5) $stop;
+      if (r-- != 2.5) $stop;
+      if (r != 1.5) $stop;
+      if (++r != 2.5) $stop;
+      if (r != 2.5) $stop;
+      if (--r != 1.5) $stop;
+      if (r != 1.5) $stop;
+
       r = 1.23456;
       s = $sformatf("%g", r);
       `checks(s, "1.23456");

test_regress/t/t_math_wide_inc.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;

test_regress/t/t_math_wide_inc.v

@@ -0,0 +1,89 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// Copyright 2023 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
+
+module t (/*AUTOARG*/
+   // Inputs
+   clk
+   );
+   input clk;
+
+   integer i;
+   reg [6:0] w7;
+   reg [14:0] w15;
+   reg [30:0] w31;
+   reg [62:0] w63;
+   reg [94:0] w95;
+
+   integer      cyc = 0;
+
+   // Test loop
+   always @ (posedge clk) begin
+`ifdef TEST_VERBOSE
+      $write("[%0t] cyc==%0d\n", $time, cyc);
+`endif
+      cyc <= cyc + 1;
+      if (cyc==0) begin
+         // Setup
+         w7 = {7{1'b1}};
+         w15 = {15{1'b1}};
+         w31 = {31{1'b1}};
+         w63 = {63{1'b1}};
+         w95 = {95{1'b1}};
+      end
+      else if (cyc == 1) begin
+         if (w7++ != {7{1'b1}}) $stop;
+         if (w7 != {7{1'b0}}) $stop;
+         if (w7-- != {7{1'b0}}) $stop;
+         if (w7 != {7{1'b1}}) $stop;
+         if (++w7 != {7{1'b0}}) $stop;
+         if (w7 != {7{1'b0}}) $stop;
+         if (--w7 != {7{1'b1}}) $stop;
+         if (w7 != {7{1'b1}}) $stop;
+
+         if (w15++ != {15{1'b1}}) $stop;
+         if (w15 != {15{1'b0}}) $stop;
+         if (w15-- != {15{1'b0}}) $stop;
+         if (w15 != {15{1'b1}}) $stop;
+         if (++w15 != {15{1'b0}}) $stop;
+         if (w15 != {15{1'b0}}) $stop;
+         if (--w15 != {15{1'b1}}) $stop;
+         if (w15 != {15{1'b1}}) $stop;
+
+         if (w31++ != {31{1'b1}}) $stop;
+         if (w31 != {31{1'b0}}) $stop;
+         if (w31-- != {31{1'b0}}) $stop;
+         if (w31 != {31{1'b1}}) $stop;
+         if (++w31 != {31{1'b0}}) $stop;
+         if (w31 != {31{1'b0}}) $stop;
+         if (--w31 != {31{1'b1}}) $stop;
+         if (w31 != {31{1'b1}}) $stop;
+
+         if (w63++ != {63{1'b1}}) $stop;
+         if (w63 != {63{1'b0}}) $stop;
+         if (w63-- != {63{1'b0}}) $stop;
+         if (w63 != {63{1'b1}}) $stop;
+         if (++w63 != {63{1'b0}}) $stop;
+         if (w63 != {63{1'b0}}) $stop;
+         if (--w63 != {63{1'b1}}) $stop;
+         if (w63 != {63{1'b1}}) $stop;
+
+         if (w95++ != {95{1'b1}}) $stop;
+         if (w95 != {95{1'b0}}) $stop;
+         if (w95-- != {95{1'b0}}) $stop;
+         if (w95 != {95{1'b1}}) $stop;
+         if (++w95 != {95{1'b0}}) $stop;
+         if (w95 != {95{1'b0}}) $stop;
+         if (--w95 != {95{1'b1}}) $stop;
+         if (w95 != {95{1'b1}}) $stop;
+      end
+      else if (cyc==99) begin
+         $write("*-* All Finished *-*\n");
+         $finish;
+      end
+   end
+endmodule