Fix constant function assigned to packed structs, bug997.

Signed-off-by: Wilson Snyder <wsnyder@wsnyder.org>

Changes

@@ -5,13 +5,15 @@ indicates the contributor was also the author of the fix; Thanks!
 
 * Verilator 3.879 devel
 
+****  Fix display %u, %v, %p, %z, bug989. [Johan Bjork]
+
 ****  Fix real parameters causing bad module names, bug992. [Johan Bjork]
 
 ****  Fix size-changing cast on packed struct, bug993. [Johan Bjork]
 
 ****  Fix function calls on arrayed interface, bug994. [Johan Bjork]
 
-****  Fix display %u, %v, %p, %z, bug989. [Johan Bjork]
+****  Fix constant function assigned to packed structs, bug997. [Johan Bjork]
 
 
 * Verilator 3.878 2015-11-01

src/V3Simulate.h

@@ -451,6 +451,56 @@ private:
 	    }
 	}
     }
+
+    bool handleAssignSel(AstNodeAssign* nodep, AstSel* selp, AstVarRef** outVarrefp, int depth) {
+	checkNodeInfo(selp);
+	AstVarRef* varrefp = selp->fromp()->castVarRef();
+	if (!varrefp) {
+	    selp = selp->lhsp()->castSel();
+	    if (selp) {
+		if (!handleAssignSel(nodep, selp, &varrefp, depth+1)) {
+		    clearOptimizable(nodep, "Select LHS isn't simple variable");
+		    return false;
+		}
+	    }
+	}
+
+	if (m_checkOnly) {
+	    nodep->iterateChildren(*this);
+	} else {
+	    selp->lsbp()->iterateAndNext(*this);
+	    nodep->rhsp()->iterateAndNext(*this);
+
+	    if (optimizable()) {
+		AstNode* vscp;
+		if (varrefp) {
+		    vscp = varOrScope(varrefp);
+		    V3Number outnum = V3Number(nodep->fileline());
+		    if (V3Number* vscpnump = fetchOutNumberNull(vscp)) {
+			outnum = *vscpnump;
+		    } else if (V3Number* vscpnump = fetchNumberNull(vscp)) {
+			outnum = *vscpnump;
+		    } else {  // Assignment to unassigned variable, all bits are X or 0
+			outnum = V3Number(nodep->fileline(), varrefp->varp()->widthMin());
+			if (varrefp->varp()->basicp() && varrefp->varp()->basicp()->isZeroInit()) {
+			    outnum.setAllBits0();
+			} else {
+			    outnum.setAllBitsX();
+			}
+		    }
+		    if (depth == 0) {
+			outnum.opSelInto(*fetchNumber(nodep->rhsp()),
+					 *fetchNumber(selp->lsbp()),
+					 selp->widthConst());
+			assignOutNumber(nodep, vscp, &outnum);
+		    }
+		}
+	    }
+	}
+	if (outVarrefp) *outVarrefp = varrefp;
+	return true;
+    }
+
     virtual void visit(AstNodeAssign* nodep, AstNUser*) {
 	if (jumpingOver(nodep)) return;
 	if (!optimizable()) return;  // Accelerate
@@ -462,41 +512,10 @@ private:
 	    if (m_anyAssignDly) clearOptimizable(nodep, "Mix of dly/non-dly assigns");
 	    m_anyAssignComb = true;
 	}
+
 	if (AstSel* selp = nodep->lhsp()->castSel()) {
 	    if (!m_params) { clearOptimizable(nodep, "LHS has select"); return; }
-	    checkNodeInfo(selp);
-	    AstVarRef* varrefp = selp->fromp()->castVarRef();
-	    if (!varrefp) {
-		clearOptimizable(nodep, "Select LHS isn't simple variable");
-		return;
-	    }
-	    if (m_checkOnly) {
-		nodep->iterateChildren(*this);
-	    } else {
-		selp->lsbp()->iterateAndNext(*this);
-		nodep->rhsp()->iterateAndNext(*this);
-		if (optimizable()) {
-		    AstNode* vscp = varOrScope(varrefp);
-		    if (optimizable()) {
-			V3Number outnum (nodep->fileline(), varrefp->varp()->widthMin());
-			if (V3Number* outnump = fetchOutNumberNull(vscp)) {
-			    outnum = *outnump;
-			} else if (V3Number* outnump = fetchNumberNull(vscp)) {
-			    outnum = *outnump;
-			} else {  // Assignment to unassigned variable, all bits are X or 0
-			    if (varrefp->varp()->basicp() && varrefp->varp()->basicp()->isZeroInit()) {
-				outnum.setAllBits0();
-			    } else {
-				outnum.setAllBitsX();
-			    }
-			}
-			outnum.opSelInto(*fetchNumber(nodep->rhsp()),
-					 *fetchNumber(selp->lsbp()),
-					 selp->widthConst());
-			assignOutNumber(nodep, vscp, &outnum);
-		    }
-		}
-	    }
+	    handleAssignSel(nodep, selp, NULL, 0);
 	}
 	else if (!nodep->lhsp()->castVarRef()) {
 	    clearOptimizable(nodep, "LHS isn't simple variable");

test_regress/t/t_func_const.v

@@ -13,6 +13,19 @@ module t;
    localparam P6 = f_return(P4);
    localparam P3 = 3;
 
+   typedef struct packed {
+      logic [7:0] data;
+   } type_t;
+   typedef type_t [1:0] flist;
+   localparam flist PLIST = {8'd4,8'd8};
+   localparam flist PARR = f_list_swap_2(PLIST);
+   typedef struct packed {
+      logic first;
+      logic second;
+      logic [31:0] data;
+   } bigstruct_t;
+   localparam bigstruct_t bigparam = f_return_struct(1'b1, 1'b0, 32'hfff12fff);
+
    initial begin
 `ifdef TEST_VERBOSE
       $display("P5=%0d P8=%0d P16=%0d P18=%0d",P5,P8,P16,P18);
@@ -24,6 +37,11 @@ module t;
       if (P8 !== 8) $stop;
       if (P16 !== 16) $stop;
       if (P18 !== 18) $stop;
+      if (PARR[0] != PLIST[1]) $stop;
+      if (PARR[1] != PLIST[0]) $stop;
+      if (bigparam.first != 1'b1) $stop;
+      if (bigparam.second != 1'b0) $stop;
+      if (bigparam.data != 32'hfff12fff) $stop;
       $write("*-* All Finished *-*\n");
       $finish;
    end
@@ -36,7 +54,7 @@ module t;
    function integer f_add2(input [31:0] a, input [31:0] b, input [31:0] c);
       f_add2 = f_add(a,b)+c;
    endfunction
-   
+
    // Speced ok: local variables
    function integer f_for(input [31:0] a);
       integer i;
@@ -84,4 +102,17 @@ module t;
       end
       f_return = 0;
    endfunction
+
+   function flist f_list_swap_2(input flist in_list);
+      f_list_swap_2[0].data = in_list[1].data;
+      f_list_swap_2[1].data = in_list[0].data;
+   endfunction
+
+   function bigstruct_t f_return_struct(input first, input second, input [31:0] data);
+      bigstruct_t result;
+      result.data = data;
+      result.first = first;
+      result.second = second;
+      return result;
+   endfunction
 endmodule