Re-apply MemorySSA: Add support for caching clobbering access in

stores with some fixes.

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: 299486

2 files changed, 9 insertions, 9 deletions

diff --git a/llvm/lib/Transforms/Utils/MemorySSA.cpp b/llvm/lib/Transforms/Utils/MemorySSA.cpp
index 5a3b163992e..79c0ac17ad3 100644
--- a/llvm/lib/Transforms/Utils/MemorySSA.cpp
+++ b/llvm/lib/Transforms/Utils/MemorySSA.cpp
@@ -2181,9 +2181,9 @@ MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
   // If this is an already optimized use or def, return the optimized result.
   // Note: Currently, we do not store the optimized def result because we'd need
   // a separate field, since we can't use it as the defining access.
-  if (MemoryUse *MU = dyn_cast<MemoryUse>(StartingAccess))
-    if (MU->isOptimized())
-      return MU->getDefiningAccess();
+  if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
+    if (MUD->isOptimized())
+      return MUD->getOptimized();
 
   const Instruction *I = StartingAccess->getMemoryInst();
   UpwardsMemoryQuery Q(I, StartingAccess);
@@ -2199,8 +2199,8 @@ MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
   if (isUseTriviallyOptimizableToLiveOnEntry(*MSSA->AA, I)) {
     MemoryAccess *LiveOnEntry = MSSA->getLiveOnEntryDef();
     Cache.insert(StartingAccess, LiveOnEntry, Q.StartingLoc, Q.IsCall);
-    if (MemoryUse *MU = dyn_cast<MemoryUse>(StartingAccess))
-      MU->setDefiningAccess(LiveOnEntry, true);
+    if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
+      MUD->setOptimized(LiveOnEntry);
     return LiveOnEntry;
   }
 
@@ -2217,8 +2217,8 @@ MemorySSA::CachingWalker::getClobberingMemoryAccess(MemoryAccess *MA) {
   DEBUG(dbgs() << *DefiningAccess << "\n");
   DEBUG(dbgs() << "Final Memory SSA clobber for " << *I << " is ");
   DEBUG(dbgs() << *Result << "\n");
-  if (MemoryUse *MU = dyn_cast<MemoryUse>(StartingAccess))
-    MU->setDefiningAccess(Result, true);
+  if (auto *MUD = dyn_cast<MemoryUseOrDef>(StartingAccess))
+    MUD->setOptimized(Result);
 
   return Result;
 }
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);
     }
   }