From bf143e2a202010bfbb03d6630235d46e1c57808f Mon Sep 17 00:00:00 2001
From: Chandler Carruth <chandlerc@gmail.com>
Date: Fri, 14 Aug 2015 00:21:10 +0000
Subject: [PATCH] [LIR] Re-instate r244880, reverted in r244884, factoring the
 handling of AliasAnalysis in LoopIdiomRecognize.

The previous commit to LIR, r244879, exposed some scary bug in the loop
pass pipeline with an assert failure that showed up on several bots.
This patch got reverted as part of getting that revision reverted, but
they're actually independent and unrelated. This patch has no functional
change and should be completely safe. It is also useful for my current
work on the AA infrastructure.

llvm-svn: 244993
---
 llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
index e3fe2530c2b8..ee5203105201 100644
--- a/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopIdiomRecognize.cpp
@@ -69,6 +69,7 @@ namespace {
 
 class LoopIdiomRecognize : public LoopPass {
   Loop *CurLoop;
+  AliasAnalysis *AA;
   DominatorTree *DT;
   LoopInfo *LI;
   ScalarEvolution *SE;
@@ -188,6 +189,7 @@ bool LoopIdiomRecognize::runOnLoop(Loop *L, LPPassManager &LPM) {
   if (Name == "memset" || Name == "memcpy")
     return false;
 
+  AA = &getAnalysis<AliasAnalysis>();
   DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
   LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
   SE = &getAnalysis<ScalarEvolution>();
@@ -505,7 +507,7 @@ bool LoopIdiomRecognize::processLoopStridedStore(
                                           Preheader->getTerminator());
 
   if (mayLoopAccessLocation(BasePtr, MRI_ModRef, CurLoop, BECount, StoreSize,
-                            getAnalysis<AliasAnalysis>(), TheStore)) {
+                            *AA, TheStore)) {
     Expander.clear();
     // If we generated new code for the base pointer, clean up.
     RecursivelyDeleteTriviallyDeadInstructions(BasePtr, TLI);
@@ -594,7 +596,7 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(
       Preheader->getTerminator());
 
   if (mayLoopAccessLocation(StoreBasePtr, MRI_ModRef, CurLoop, BECount,
-                            StoreSize, getAnalysis<AliasAnalysis>(), SI)) {
+                            StoreSize, *AA, SI)) {
     Expander.clear();
     // If we generated new code for the base pointer, clean up.
     RecursivelyDeleteTriviallyDeadInstructions(StoreBasePtr, TLI);
@@ -608,7 +610,7 @@ bool LoopIdiomRecognize::processLoopStoreOfLoopLoad(
       Preheader->getTerminator());
 
   if (mayLoopAccessLocation(LoadBasePtr, MRI_Mod, CurLoop, BECount, StoreSize,
-                            getAnalysis<AliasAnalysis>(), SI)) {
+                            *AA, SI)) {
     Expander.clear();
     // If we generated new code for the base pointer, clean up.
     RecursivelyDeleteTriviallyDeadInstructions(LoadBasePtr, TLI);