From ea51f62e4bdd494f0186633e77ff5e5085aa378e Mon Sep 17 00:00:00 2001
From: Benjamin Kramer <benny.kra@googlemail.com>
Date: Thu, 16 Feb 2012 13:49:39 +0000
Subject: InstSimplify: Ignore pointer casts when constant folding compares
 between pointers.

llvm-svn: 150690
---
 llvm/lib/Analysis/InstructionSimplify.cpp | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

(limited to 'llvm/lib/Analysis/InstructionSimplify.cpp')

diff --git a/llvm/lib/Analysis/InstructionSimplify.cpp b/llvm/lib/Analysis/InstructionSimplify.cpp
index 7656220ba1f..9d5b74c8cf2 100644
--- a/llvm/lib/Analysis/InstructionSimplify.cpp
+++ b/llvm/lib/Analysis/InstructionSimplify.cpp
@@ -1591,8 +1591,11 @@ static Value *SimplifyICmpInst(unsigned Predicate, Value *LHS, Value *RHS,
   // to the case where LHS is a global variable address or null is pointless,
   // since if both LHS and RHS are constants then we already constant folded
   // the compare, and if only one of them is then we moved it to RHS already.
-  if (isa<AllocaInst>(LHS) && (isa<GlobalValue>(RHS) || isa<AllocaInst>(RHS) ||
-                               isa<ConstantPointerNull>(RHS)))
+  Value *LHSPtr = LHS->stripPointerCasts();
+  Value *RHSPtr = RHS->stripPointerCasts();
+  if (isa<AllocaInst>(LHSPtr) && (isa<GlobalValue>(RHSPtr) ||
+                                  isa<AllocaInst>(RHSPtr)  ||
+                                  isa<ConstantPointerNull>(RHSPtr)))
     // We already know that LHS != RHS.
     return ConstantInt::get(ITy, CmpInst::isFalseWhenEqual(Pred));
 
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