From e77b7427b49c7b9c02935f46208eed451bdfe3fd Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Tue, 10 Jun 2014 19:13:55 -0400
Subject: [PATCH] Fix shift corner-case, bug 774.

---
 Changes                         |  2 +-
 src/V3Expand.cpp                |  4 ++--
 test_regress/t/t_math_signed5.v | 10 ++++++++--
 3 files changed, 11 insertions(+), 5 deletions(-)

diff --git a/Changes b/Changes
index e261897e5..3ee8cd4ee 100644
--- a/Changes
+++ b/Changes
@@ -21,7 +21,7 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ****  Fix pattern assignment to conditionals, bug769. [Jie Xu]
 
-****  Fix shift corner-cases, bug765, bug766, bug768, bug772, bug776. [Clifford Wolf]
+****  Fix shift corner-cases, bug765, bug766, bug768, bug772, bug774, bug776. [Clifford Wolf]
 
 ****  Fix C compiler interpreting signing, bug773. [Clifford Wolf]
 
diff --git a/src/V3Expand.cpp b/src/V3Expand.cpp
index bb7293e52..f2a7fbf82 100644
--- a/src/V3Expand.cpp
+++ b/src/V3Expand.cpp
@@ -448,8 +448,8 @@ private:
 	    AstNode* newp = new AstShiftR (nodep->fileline(),
 					   fromp,
 					   dropCondBound(lsbp),
-					   nodep->width());
-	    newp->dtypeFrom(nodep);
+					   fromp->width());  // {large}>>32 requires 64-bit shift operation; then cast
+	    newp->dtypeFrom(fromp);
 	    if (!nodep->isQuad() && fromp->isQuad()) {
 		newp = new AstCCast (newp->fileline(), newp, nodep);
 	    }
diff --git a/test_regress/t/t_math_signed5.v b/test_regress/t/t_math_signed5.v
index 0f4585066..3bd62b75e 100644
--- a/test_regress/t/t_math_signed5.v
+++ b/test_regress/t/t_math_signed5.v
@@ -147,11 +147,17 @@
 `endif
 
       // bug773
-      w5_u = `c(31, "31");
+      w5_u = `c(31, 31);
       w5_s = w5_u >> ((w5_u ? 1 : 2) << w5_u);
       `checkh(w5_s, 5'b0);
 
-      //bug776
+      // bug774
+      w4_u = `c(4, 5);
+      w6_u = `c(6, 35);
+      w4_u = 64'd0 | (w4_u << w6_u);
+      `checkh(w4_u, 0);
+
+      // bug776
       w4_u = `c(4, 1);
       w4_u = (w4_u >> w4_u) ^~ (w4_u >> w4_u);
       `checkh(w4_u, 4'b1111);