[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.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@244993 91177308-0d34-0410-b5e6-96231b3b80d8

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);