When emitting code for an add, don't force a SCEVUnknown wrapper around

a hoisted intermediate result if the intermediate result isn't an
Instruction.

llvm-svn: 100884

1 files changed, 4 insertions, 3 deletions

diff --git a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
index 24825bf5e56..1d1339078de 100644
--- a/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
+++ b/llvm/lib/Analysis/ScalarEvolutionExpander.cpp
@@ -705,10 +705,11 @@ 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. Use a SCEVUnknown so that we don't
-      // re-analyze the instructions that we just emitted.
+      // 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));