commit cd5f37f3f100beda0370da6e49135f036bbac772
author John Brawn <john.brawn@arm.com> Tue Jul 31 14:19:29 2018 +0000
committer John Brawn <john.brawn@arm.com> Tue Jul 31 14:19:29 2018 +0000
tree 21832a65f276b1b2bfe45ec5ba3fa2bce6193314
parent 16d8a69b90df2effd11315769fefac378cc57aa1

[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

llvm/lib/Analysis/MemoryDependenceAnalysis.cpp

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 @@
   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 @@
     }
   }
 
+  // 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 @@
   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(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 @@
   AU.setPreservesAll();
   AU.addRequired<AssumptionCacheTracker>();
   AU.addRequired<DominatorTreeWrapperPass>();
+  AU.addRequired<PhiValuesWrapperPass>();
   AU.addRequiredTransitive<AAResultsWrapperPass>();
   AU.addRequiredTransitive<TargetLibraryInfoWrapperPass>();
 }
@@ -1773,7 +1782,8 @@
   // 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 @@
   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;
 }