MemorySSA: Add support for caching clobbering access in stores

Summary:
This enables us to cache the clobbering access for stores, despite the
fact that we can't rewrite the use-def chains themselves.

Early testing shows that, after this change, for larger testcases, it will be a significant net positive (memory and time) to remove the walker caching.

Reviewers: george.burgess.iv, davide

Subscribers: Prazek, llvm-commits

Differential Revision: https://reviews.llvm.org/D31567

llvm-svn: 299322

1 files changed, 2 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Utils/MemorySSAUpdater.cpp b/llvm/lib/Transforms/Utils/MemorySSAUpdater.cpp
index 7e043956171..c396bd73504 100644
--- a/llvm/lib/Transforms/Utils/MemorySSAUpdater.cpp
+++ b/llvm/lib/Transforms/Utils/MemorySSAUpdater.cpp
@@ -451,8 +451,8 @@ void MemorySSAUpdater::removeMemoryAccess(MemoryAccess *MA) {
 
     while (!MA->use_empty()) {
       Use &U = *MA->use_begin();
-      if (MemoryUse *MU = dyn_cast<MemoryUse>(U.getUser()))
-        MU->resetOptimized();
+      if (auto *MUD = dyn_cast<MemoryUseOrDef>(U.getUser()))
+        MUD->resetOptimized();
       U.set(NewDefTarget);
     }
   }