Don't load values out of global constants with weak

[oota-llvm.git] / lib / Transforms / Scalar / InstructionCombining.cpp

diff --git a/lib/Transforms/Scalar/InstructionCombining.cpp b/lib/Transforms/Scalar/InstructionCombining.cpp
index 4a7f4c74f3358d60e54cb1aa3000bc3290b6eb10..10671cd908b767ca2cd88e4a96ea4c1de4316f11 100644 (file)
--- a/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -11215,14 +11215,15 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
 
     // Instcombine load (constant global) into the value loaded.
     if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op))
-      if (GV->isConstant() && !GV->isDeclaration())
+      if (GV->isConstant() && !GV->isDeclaration() && !GV->mayBeOverridden())
         return ReplaceInstUsesWith(LI, GV->getInitializer());
 
     // Instcombine load (constantexpr_GEP global, 0, ...) into the value loaded.
     if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op)) {
       if (CE->getOpcode() == Instruction::GetElementPtr) {
         if (GlobalVariable *GV = dyn_cast<GlobalVariable>(CE->getOperand(0)))
-          if (GV->isConstant() && !GV->isDeclaration())
+          if (GV->isConstant() && !GV->isDeclaration() &&
+              !GV->mayBeOverridden())
             if (Constant *V = 
                ConstantFoldLoadThroughGEPConstantExpr(GV->getInitializer(), CE))
               return ReplaceInstUsesWith(LI, V);
@@ -11246,7 +11247,7 @@ Instruction *InstCombiner::visitLoadInst(LoadInst &LI) {
   // If this load comes from anywhere in a constant global, and if the global
   // is all undef or zero, we know what it loads.
   if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Op->getUnderlyingObject())){
-    if (GV->isConstant() && GV->hasInitializer()) {
+    if (GV->isConstant() && GV->hasInitializer() && !GV->mayBeOverridden()) {
       if (GV->getInitializer()->isNullValue())
         return ReplaceInstUsesWith(LI, Constant::getNullValue(LI.getType()));
       else if (isa<UndefValue>(GV->getInitializer()))