Fix PR5471 by removing an instcombine xform. Some pieces of the code

generates store to undef and some generates store to null as the idiom
for undefined behavior.  Since simplifycfg zaps both, don't remove the
undefined behavior in instcombine.

llvm-svn: 89971

1 files changed, 0 insertions, 6 deletions

diff --git a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
index 670dd1162bd..f997d60a85e 100644
--- a/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/Scalar/InstructionCombining.cpp
@@ -12096,12 +12096,6 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
   Value *Val = SI.getOperand(0);
   Value *Ptr = SI.getOperand(1);
 
-  if (isa<UndefValue>(Ptr)) {     // store X, undef -> noop (even if volatile)
-    EraseInstFromFunction(SI);
-    ++NumCombined;
-    return 0;
-  }
-  
   // If the RHS is an alloca with a single use, zapify the store, making the
   // alloca dead.
   // If the RHS is an alloca with a two uses, the other one being a