Revert r320407 "[InstCombine] Fix PR35618: Instcombine hangs on single minmax load bitcast."

The tests fail (opt asserts) on Windows.

> Summary:
> If we have pattern `store (load(bitcast(select (cmp(V1, V2), &V1,
> &V2)))), bitcast)`, but the load is used in other instructions, it leads
> to looping in InstCombiner. Patch adds additional check that all users
> of the load instructions are stores and then replaces all uses of load
> instruction by the new one with new type.
>
> Reviewers: RKSimon, spatel, majnemer
>
> Subscribers: llvm-commits
>
> Differential Revision: https://reviews.llvm.org/D41072

llvm-svn: 320421

1 files changed, 2 insertions, 17 deletions

diff --git a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
index a729981a549..29e0a091aa7 100644
--- a/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstCombineLoadStoreAlloca.cpp
@@ -1344,24 +1344,9 @@ bool removeBitcastsFromLoadStoreOnMinMax(InstCombiner &IC, StoreInst &SI) {
   if (!isMinMaxWithLoads(LoadAddr))
     return false;
 
-  if (!all_of(LI->users(), [LI](User *U) {
-        auto *SI = dyn_cast<StoreInst>(U);
-        return SI && SI->getPointerOperand() != LI &&
-               !SI->getPointerOperand()->isSwiftError();
-      }))
-    return false;
-
-  IC.Builder.SetInsertPoint(LI);
   LoadInst *NewLI = combineLoadToNewType(
       IC, *LI, LoadAddr->getType()->getPointerElementType());
-  // Replace all the stores with stores of the newly loaded value.
-  for (auto *UI : LI->users()) {
-    auto *SI = cast<StoreInst>(UI);
-    IC.Builder.SetInsertPoint(SI);
-    combineStoreToNewValue(IC, *SI, NewLI);
-    IC.eraseInstFromFunction(*SI);
-  }
-  IC.eraseInstFromFunction(*LI);
+  combineStoreToNewValue(IC, SI, NewLI);
   return true;
 }
 
@@ -1390,7 +1375,7 @@ Instruction *InstCombiner::visitStoreInst(StoreInst &SI) {
     return eraseInstFromFunction(SI);
 
   if (removeBitcastsFromLoadStoreOnMinMax(*this, SI))
-    return nullptr;
+    return eraseInstFromFunction(SI);
 
   // Replace GEP indices if possible.
   if (Instruction *NewGEPI = replaceGEPIdxWithZero(*this, Ptr, SI)) {