From f9bbf31d6538e73acbfd5a0c77f78b960687e4b6 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Tue, 9 Aug 2011 19:56:22 -0400
Subject: [PATCH] Fix internal error on integer casts, bug374.

---
 Changes                      |  4 ++++
 src/V3Width.cpp              |  7 ++++---
 test_regress/t/t_math_real.v | 11 ++++++++++-
 3 files changed, 18 insertions(+), 4 deletions(-)

diff --git a/Changes b/Changes
index 8b079ea4d..f1b9b5508 100644
--- a/Changes
+++ b/Changes
@@ -3,6 +3,10 @@ Revision history for Verilator
 The contributors that suggested a given feature are shown in [].  [by ...]
 indicates the contributor was also the author of the fix; Thanks!
 
+* Verilator 3.821****
+
+**** Fix internal error on integer casts, bug374. [Chandan Egbert]
+
 * Verilator 3.820 2011/07/28
 
 **   Support 'real' numbers and related functions.
diff --git a/src/V3Width.cpp b/src/V3Width.cpp
index 4b0b8cbff..53bd58bdb 100644
--- a/src/V3Width.cpp
+++ b/src/V3Width.cpp
@@ -642,10 +642,11 @@ private:
 	V3Width::widthParamsEdit(nodep->dtypep()); // MAY CHANGE dtypep()
 	AstBasicDType* basicp = nodep->dtypep()->basicp();  if (!basicp) nodep->v3fatalSrc("Unimplemented: Casting non-simple data type");
 	nodep->widthSignedFrom(basicp);
-	AstNode* newp = nodep->lhsp()->unlinkFrBack();
-	if (!basicp->isDouble() && !newp->isDouble()) {
-	    widthCheck(nodep,"Cast",newp,nodep->width(),nodep->width(),true);
+	if (!basicp->isDouble() && !nodep->lhsp()->isDouble()) {
+	    // Note widthCheck might modify nodep->lhsp()
+	    widthCheck(nodep,"Cast",nodep->lhsp(),nodep->width(),nodep->width(),true);
 	}
+	AstNode* newp = nodep->lhsp()->unlinkFrBack();
 	if (basicp->numeric() == newp->numeric()) {
 	    newp = newp; // Can just remove cast
 	} else if (basicp->isDouble() && !newp->isDouble()) {
diff --git a/test_regress/t/t_math_real.v b/test_regress/t/t_math_real.v
index e97b46e52..9fc2c7749 100644
--- a/test_regress/t/t_math_real.v
+++ b/test_regress/t/t_math_real.v
@@ -19,6 +19,8 @@ module t (/*AUTOARG*/
    realtime  uninit;
    initial if (uninit != 0.0) $stop;
 
+   sub_cast_bug374 sub (.cyc5(cyc[4:0]), .*);
+
    initial begin
       // rtoi truncates
       if ($rtoi(36.7) != 36) $stop;
@@ -132,5 +134,12 @@ module t (/*AUTOARG*/
 	 $finish;
       end
    end
-
+endmodule
+
+module sub_cast_bug374(input clk, input [4:0] cyc5);
+    integer i;
+
+    always @(posedge clk) begin
+       i <= integer'(cyc5);
+    end
 endmodule