[MemDep] Use PhiValuesAnalysis to improve alias analysis results

This is being done in order to make GVN able to better optimize certain inputs.
MemDep doesn't use PhiValues directly, but does need to notifiy it when things
get invalidated.

Differential Revision: https://reviews.llvm.org/D48489

llvm-svn: 338384

1 files changed, 14 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
index 7eeefd5..feae53c 100644
--- a/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/MemoryDependenceAnalysis.cpp
@@ -26,6 +26,7 @@
 #include "llvm/Analysis/MemoryLocation.h"
 #include "llvm/Analysis/OrderedBasicBlock.h"
 #include "llvm/Analysis/PHITransAddr.h"
+#include "llvm/Analysis/PhiValues.h"
 #include "llvm/Analysis/TargetLibraryInfo.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/Attributes.h"
@@ -1513,6 +1514,8 @@ void MemoryDependenceResults::invalidateCachedPointerInfo(Value *Ptr) {
   RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, false));
   // Flush load info for the pointer.
   RemoveCachedNonLocalPointerDependencies(ValueIsLoadPair(Ptr, true));
+  // Invalidate phis that use the pointer.
+  PV.invalidateValue(Ptr);
 }
 
 void MemoryDependenceResults::invalidateCachedPredecessors() {
@@ -1671,6 +1674,9 @@ void MemoryDependenceResults::removeInstruction(Instruction *RemInst) {
     }
   }
 
+  // Invalidate phis that use the removed instruction.
+  PV.invalidateValue(RemInst);
+
   assert(!NonLocalDeps.count(RemInst) && "RemInst got reinserted?");
   LLVM_DEBUG(verifyRemoved(RemInst));
 }
@@ -1730,7 +1736,8 @@ MemoryDependenceAnalysis::run(Function &F, FunctionAnalysisManager &AM) {
   auto &AC = AM.getResult<AssumptionAnalysis>(F);
   auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
   auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
-  return MemoryDependenceResults(AA, AC, TLI, DT);
+  auto &PV = AM.getResult<PhiValuesAnalysis>(F);
+  return MemoryDependenceResults(AA, AC, TLI, DT, PV);
 }
 
 char MemoryDependenceWrapperPass::ID = 0;
@@ -1741,6 +1748,7 @@ INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
 INITIALIZE_PASS_DEPENDENCY(AAResultsWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfoWrapperPass)
+INITIALIZE_PASS_DEPENDENCY(PhiValuesWrapperPass)
 INITIALIZE_PASS_END(MemoryDependenceWrapperPass, "memdep",
                     "Memory Dependence Analysis", false, true)
 
@@ -1758,6 +1766,7 @@ void MemoryDependenceWrapperPass::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesAll();
   AU.addRequired<AssumptionCacheTracker>();
   AU.addRequired<DominatorTreeWrapperPass>();
+  AU.addRequired<PhiValuesWrapperPass>();
   AU.addRequiredTransitive<AAResultsWrapperPass>();
   AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>();
 }
@@ -1773,7 +1782,8 @@ bool MemoryDependenceResults::invalidate(Function &F, const PreservedAnalyses &P
   // Check whether the analyses we depend on became invalid for any reason.
   if (Inv.invalidate<AAManager>(F, PA) ||
       Inv.invalidate<AssumptionAnalysis>(F, PA) ||
-      Inv.invalidate<DominatorTreeAnalysis>(F, PA))
+      Inv.invalidate<DominatorTreeAnalysis>(F, PA) ||
+      Inv.invalidate<PhiValuesAnalysis>(F, PA))
     return true;
 
   // Otherwise this analysis result remains valid.
@@ -1789,6 +1799,7 @@ bool MemoryDependenceWrapperPass::runOnFunction(Function &F) {
   auto &AC = getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
   auto &TLI = getAnalysis<TargetLibraryInfoWrapperPass>().getTLI();
   auto &DT = getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-  MemDep.emplace(AA, AC, TLI, DT);
+  auto &PV = getAnalysis<PhiValuesWrapperPass>().getResult();
+  MemDep.emplace(AA, AC, TLI, DT, PV);
   return false;
 }