Support <number>'() sized casts, bug628.

Changes

@@ -20,6 +20,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ****  Support bind in $unit, bug602. [Ed Lander]
 
+****  Support <number>'() sized casts, bug628. [Ed Lander]
+
 ****  Fix DETECTARRAY on packed structures, bug610. [Jeremy Bennett]
 
 ****  Fix LITENDIAN on unpacked structures, bug614. [Wai Sum Mong]

src/V3AstNodes.h

@@ -3184,6 +3184,20 @@ struct AstCast : public AstNode {
     AstNodeDType* childDTypep() const { return op2p()->castNodeDType(); }
 };
 
+struct AstCastSize : public AstNode {
+    // Cast to specific size; signed/twostate inherited from lower element per IEEE
+    AstCastSize(FileLine* fl, AstNode* lhsp, AstConst* rhsp) : AstNode(fl) {
+	setOp1p(lhsp); setOp2p(rhsp);
+    }
+    ASTNODE_NODE_FUNCS(CastSize, CASTSIZE)
+    virtual string emitVerilog() { return "((%r)'(%l))"; }
+    virtual string emitC() { V3ERROR_NA; return ""; }
+    virtual bool cleanOut() { V3ERROR_NA; return true;} virtual bool cleanLhs() {return true;}
+    virtual bool sizeMattersLhs() {return false;}
+    AstNode* lhsp() const { return op1p(); }
+    AstNode* rhsp() const { return op2p(); }
+};
+
 struct AstCCast : public AstNodeUniop {
     // Cast to C-based data type
 private:

src/V3Width.cpp

@@ -805,6 +805,28 @@ private:
 	pushDeletep(nodep); nodep=NULL;
 	//if (debug()) newp->dumpTree(cout,"  CastOut: ");
     }
+    virtual void visit(AstCastSize* nodep, AstNUser* vup) {
+	if (!nodep->rhsp()->castConst()) nodep->v3fatalSrc("Unsupported: Non-const cast of size");
+	//if (debug()) nodep->dumpTree(cout,"  CastPre: ");
+	int width = nodep->rhsp()->castConst()->toSInt();
+	if (width < 1) { nodep->v3error("Size-changing cast to zero or negative size"); width=1; }
+	nodep->lhsp()->iterateAndNext(*this,WidthVP(ANYSIZE,0,BOTH).p());
+	AstBasicDType* underDtp = nodep->lhsp()->dtypep()->castBasicDType();
+	if (!underDtp) {
+	    nodep->v3error("Unsupported: Size-changing cast on non-basic data type");
+	    underDtp = nodep->findLogicBoolDType()->castBasicDType();
+	}
+	AstNodeDType* newDtp = (underDtp->keyword().isFourstate()
+				? nodep->findLogicDType(width, width, underDtp->numeric())
+				: nodep->findBitDType(width, width, underDtp->numeric()));
+	nodep->dtypep(newDtp);
+	AstNode* underp = nodep->lhsp()->unlinkFrBack();
+	nodep->replaceWith(underp);
+	if (underp->width()!=width) {
+	    fixWidthExtend(underp, newDtp);
+	}
+	pushDeletep(nodep); nodep=NULL;
+    }
     virtual void visit(AstVar* nodep, AstNUser* vup) {
 	//if (debug()) nodep->dumpTree(cout,"  InitPre: ");
 	// Must have deterministic constant width

src/verilog.y

@@ -2825,6 +2825,7 @@ expr<nodep>:			// IEEE: part of expression/constant_expression/primary
 	//			// Spec only allows primary with addition of a type reference
 	//			// We'll be more general, and later assert LHS was a type.
 	//UNSUP	~l~expr yP_TICK '(' expr ')'		{ UNSUP }
+	|	yaINTNUM     yP_TICK '(' expr ')'	{ $$ = new AstCastSize($2,$4,new AstConst($1->fileline(),*$1)); }
 	//
 	//			// IEEE: assignment_pattern_expression
 	//			// IEEE: streaming_concatenation

test_regress/t/t_cast.v

@@ -10,11 +10,14 @@ module t;
 
    mc_t o;
 
+   logic [15:0] allones = 16'hffff;
+
    initial begin
       if (4'shf > 4'sh0) $stop;
       if (signed'(4'hf) > 4'sh0) $stop;
       if (4'hf < 4'h0) $stop;
       if (unsigned'(4'shf) < 4'h0) $stop;
+      if (4'(allones) !== 4'hf) $stop;
 
       o = tocast_t'(4'b1);
       if (o != 4'b1) $stop;