Fix LSR to tolerate cases where ScalarEvolution initially

[oota-llvm.git] / lib / Analysis / ScalarEvolutionExpander.cpp

diff --git a/lib/Analysis/ScalarEvolutionExpander.cpp b/lib/Analysis/ScalarEvolutionExpander.cpp
index dd8ab431f34433d48a6396d461c1e040d44ae46f..b90f0515a424d38aee72c48ba74158ec7da6b795 100644 (file)
--- a/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -642,6 +642,8 @@ static const Loop *GetRelevantLoop(const SCEV *S, LoopInfo &LI,
   llvm_unreachable("Unexpected SCEV type!");
 }
 
+namespace {
+
 /// LoopCompare - Compare loops by PickMostRelevantLoop.
 class LoopCompare {
   DominatorTree &DT;
@@ -668,6 +670,8 @@ public:
   }
 };
 
+}
+
 Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
   const Type *Ty = SE.getEffectiveSCEVType(S->getType());
 
@@ -705,9 +709,11 @@ Value *SCEVExpander::visitAddExpr(const SCEVAddExpr *S) {
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, Sum);
     } else if (const PointerType *PTy = dyn_cast<PointerType>(Op->getType())) {
       // The running sum is an integer, and there's a pointer at this level.
-      // Try to form a getelementptr.
+      // Try to form a getelementptr. If the running sum is instructions,
+      // use a SCEVUnknown to avoid re-analyzing them.
       SmallVector<const SCEV *, 4> NewOps;
-      NewOps.push_back(SE.getUnknown(Sum));
+      NewOps.push_back(isa<Instruction>(Sum) ? SE.getUnknown(Sum) :
+                                               SE.getSCEV(Sum));
       for (++I; I != E && I->first == CurLoop; ++I)
         NewOps.push_back(I->second);
       Sum = expandAddToGEP(NewOps.begin(), NewOps.end(), PTy, Ty, expand(Op));