[LoopAccesses] Change LAA:getInfo to return a constant reference

As expected, this required a few more const-correctness fixes.

Based on Hal's feedback on D7684.

llvm-svn: 229899
diff --git a/llvm/lib/Analysis/LoopAccessAnalysis.cpp b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
index e9815eb..21d4d96 100644
--- a/llvm/lib/Analysis/LoopAccessAnalysis.cpp
+++ b/llvm/lib/Analysis/LoopAccessAnalysis.cpp
@@ -1198,7 +1198,7 @@
   Report = Message;
 }
 
-bool LoopAccessInfo::isUniform(Value *V) {
+bool LoopAccessInfo::isUniform(Value *V) const {
   return (SE->isLoopInvariant(SE->getSCEV(V), TheLoop));
 }
 
@@ -1214,7 +1214,7 @@
 }
 
 std::pair<Instruction *, Instruction *>
-LoopAccessInfo::addRuntimeCheck(Instruction *Loc) {
+LoopAccessInfo::addRuntimeCheck(Instruction *Loc) const {
   Instruction *tnullptr = nullptr;
   if (!PtrRtCheck.Need)
     return std::pair<Instruction *, Instruction *>(tnullptr, tnullptr);
@@ -1326,7 +1326,8 @@
   OS << "\n";
 }
 
-LoopAccessInfo &LoopAccessAnalysis::getInfo(Loop *L, ValueToValueMap &Strides) {
+const LoopAccessInfo &LoopAccessAnalysis::getInfo(Loop *L,
+                                                  ValueToValueMap &Strides) {
   auto &LAI = LoopAccessInfoMap[L];
 
 #ifndef NDEBUG