Fix concats with no argments mis-sign extending, bug759.

Changes

@@ -11,9 +11,10 @@ indicates the contributor was also the author of the fix; Thanks!
 
 **    Support streaming operators, bug649. [Glen Gibb]
 
-**    Fix expression problems with -Wno-WIDTH, bug729, bug736, bug737. [Clifford Wolf]
+**    Fix expression problems with -Wno-WIDTH, bug729, bug736, bug737, bug759.
       Where WIDTH warnings were ignored this might result in different
       warning messages and results, though it should better match the spec.
+      [Clifford Wolf]
 
 ***   Add --no-trace-params.
 

src/V3AstNodes.h

@@ -4164,6 +4164,8 @@ struct AstConcat : public AstNodeBiop {
     virtual int instrCount()	const { return widthInstrs()*2; }
 };
 struct AstReplicate : public AstNodeBiop {
+    // Also used as a "Uniop" flavor of Concat, e.g. "{a}"
+    // Verilog {rhs{lhs}} - Note rhsp() is the replicate value, not the lhsp()
 private:
     void init() {
 	if (lhsp()) {
@@ -4173,7 +4175,6 @@ private:
 	}
     }
 public:
-    // Verilog {rhs{lhs}} - Note rhsp() is the replicate value, not the lhsp()
     AstReplicate(FileLine* fl, AstNode* lhsp, AstNode* rhsp)
         : AstNodeBiop(fl, lhsp, rhsp) { init(); }
     AstReplicate(FileLine* fl, AstNode* lhsp, uint32_t repCount)

src/verilog.y

@@ -3003,7 +3003,8 @@ exprNoStr<nodep>:		// expression with string removed
 exprOkLvalue<nodep>:		// expression that's also OK to use as a variable_lvalue
 		~l~exprScope				{ $$ = $1; }
 	//			// IEEE: concatenation/constant_concatenation
-	|	'{' cateList '}'			{ $$ = $2; }
+	//			// Replicate(1) required as otherwise "{a}" would not be self-determined
+	|	'{' cateList '}'			{ $$ = new AstReplicate($1,$2,1); }
 	//			// IEEE: assignment_pattern_expression
 	//			// IEEE: [ assignment_pattern_expression_type ] == [ ps_type_id /ps_paremeter_id/data_type]
 	//			// We allow more here than the spec requires

test_regress/t/t_math_signed4.v

@@ -18,6 +18,7 @@ module t (/*AUTOARG*/);
    reg signed [4:0] w5_s;
    reg [3:0] w4_u;
    reg [4:0] w5_u;
+   reg signed [8:0] w9_s;
    real      r;
    initial begin
       // verilator lint_off WIDTH
@@ -93,7 +94,11 @@ module t (/*AUTOARG*/);
 
       // bug754
       w5_u = 4'sb0010 << -2'sd1;  // << 3
+`ifdef VCS
+      `checkh(w5_u, 5'b00000);  // VCS E-2014.03 bug
+`else
       `checkh(w5_u, 5'b10000);  // VCS E-2014.03 bug
+`endif
       w5_u = 4'sb1000 << 0;   // Sign extends
       `checkh(w5_u, 5'b11000);
 
@@ -112,6 +117,22 @@ module t (/*AUTOARG*/);
 	default: $stop;
       endcase
 
+      // bug759
+      w5_u = { -4'sd7 };
+      `checkh(w5_u, 5'b01001);
+      w5_u = {2{ -2'sd1 }};
+      `checkh(w5_u, 5'b01111);
+      // Don't break concats....
+      w5_u = {{0{1'b1}}, -4'sd7 };
+      `checkh(w5_u, 5'b01001);
+      w9_s = { -4'sd7, -4'sd7 };
+      `checkh(w9_s, 9'b010011001);
+      {w5_u, {w4_u}} = 9'b10101_1100;
+      `checkh(w5_u, 5'b10101);
+      `checkh(w4_u, 4'b1100);
+      {w4_u} = 4'b1011;
+      `checkh(w4_u, 4'b1011);
+
       if (fail) $stop;
       $write("*-* All Finished *-*\n");
       $finish;

test_regress/t/t_param_concat_bad.pl

@@ -15,7 +15,7 @@ compile (
 '%Warning-WIDTHCONCAT: t/t_param_concat.v:\d+: Unsized numbers/parameters not allowed in concatenations.
 %Warning-WIDTHCONCAT: Use "/\* verilator lint_off WIDTHCONCAT \*/" and lint_on around source to disable this message.
 %Warning-WIDTHCONCAT: t/t_param_concat.v:\d+: Unsized numbers/parameters not allowed in replications.
-%Error: Exiting due to.*',
+.*%Error: Exiting due to.*',
 	 );
 
 ok(1);