From ba689b33152d195202e58471d16a49930c8435b3 Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Sun, 25 Aug 2013 10:46:39 +0000
Subject: Fix a bug where we would corrupt the offset when evaluating a
 non-constant GEP.

I don't have any test case that demonstrates this, Nadav (indirectly)
pointed this out in code review. I'm not sure how possible it is to
contrive a test case for the current users of this code that triggers
the bad issue sadly.

llvm-svn: 189188
---
 llvm/lib/IR/Value.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

(limited to 'llvm/lib/IR/Value.cpp')

diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
index afa9291c9ef..6698f832b25 100644
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -411,8 +411,10 @@ Value *Value::stripAndAccumulateInBoundsConstantOffsets(const DataLayout &DL,
     if (GEPOperator *GEP = dyn_cast<GEPOperator>(V)) {
       if (!GEP->isInBounds())
         return V;
-      if (!GEP->accumulateConstantOffset(DL, Offset))
+      APInt GEPOffset(Offset);
+      if (!GEP->accumulateConstantOffset(DL, GEPOffset))
         return V;
+      Offset = GEPOffset;
       V = GEP->getPointerOperand();
     } else if (Operator::getOpcode(V) == Instruction::BitCast) {
       V = cast<Operator>(V)->getOperand(0);
-- 
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