From: Dan Gohman <gohman@apple.com>
Date: Tue, 25 Aug 2009 17:56:57 +0000 (+0000)
Subject: Don't assume that two identical instructions that read from memory
X-Git-Url: http://plrg.eecs.uci.edu/git/?a=commitdiff_plain;h=041de42d42f67ab6bb3d012805621e5b7adcc7d9;p=oota-llvm.git

Don't assume that two identical instructions that read from memory
will always return the same value. This isn't currently necessary,
since this code doesn't currently ever get called under circumstances
where it would matter, but it may some day.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@80017 91177308-0d34-0410-b5e6-96231b3b80d8
---

diff --git a/lib/Analysis/ScalarEvolution.cpp b/lib/Analysis/ScalarEvolution.cpp
index 33d8a18412d..d639aee7099 100644
--- a/lib/Analysis/ScalarEvolution.cpp
+++ b/lib/Analysis/ScalarEvolution.cpp
@@ -4349,7 +4349,7 @@ static bool HasSameValue(const SCEV *A, const SCEV *B) {
     if (const SCEVUnknown *BU = dyn_cast<SCEVUnknown>(B))
       if (const Instruction *AI = dyn_cast<Instruction>(AU->getValue()))
         if (const Instruction *BI = dyn_cast<Instruction>(BU->getValue()))
-          if (AI->isIdenticalTo(BI))
+          if (AI->isIdenticalTo(BI) && !AI->mayReadFromMemory())
             return true;
 
   // Otherwise assume they may have a different value.