Fix SimplifyLibcalls and ValueTracking to check mayBeOverridden

before performing optimizations based on constant string values.

llvm-svn: 79384

2 files changed, 4 insertions, 2 deletions

diff --git a/llvm/lib/Analysis/ValueTracking.cpp b/llvm/lib/Analysis/ValueTracking.cpp
index 604d10c68b9..3ab10c55d81 100644
--- a/llvm/lib/Analysis/ValueTracking.cpp
+++ b/llvm/lib/Analysis/ValueTracking.cpp
@@ -1061,7 +1061,8 @@ bool llvm::GetConstantStringInfo(Value *V, std::string &Str, uint64_t Offset,
   // variable that is a constant and is initialized. The referenced constant
   // initializer is the array that we'll use for optimization.
   GlobalVariable* GV = dyn_cast<GlobalVariable>(V);
-  if (!GV || !GV->isConstant() || !GV->hasInitializer())
+  if (!GV || !GV->isConstant() || !GV->hasInitializer() ||
+      GV->mayBeOverridden())
     return false;
   Constant *GlobalInit = GV->getInitializer();
   
diff --git a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
index 02b26bdac2b..761c309c200 100644
--- a/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
+++ b/llvm/lib/Transforms/Scalar/SimplifyLibCalls.cpp
@@ -438,7 +438,8 @@ static uint64_t GetStringLengthH(Value *V, SmallPtrSet<PHINode*, 32> &PHIs) {
   // variable that is a constant and is initialized. The referenced constant
   // initializer is the array that we'll use for optimization.
   GlobalVariable* GV = dyn_cast<GlobalVariable>(GEP->getOperand(0));
-  if (!GV || !GV->isConstant() || !GV->hasInitializer())
+  if (!GV || !GV->isConstant() || !GV->hasInitializer() ||
+      GV->mayBeOverridden())
     return 0;
   Constant *GlobalInit = GV->getInitializer();