Don't attempt to simplify an non-affine IV expression if it can't
be simplified to a loop-invariant value. This fixes PR4315.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@72798 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Scalar/IndVarSimplify.cpp b/lib/Transforms/Scalar/IndVarSimplify.cpp
index ca7aa7b..af61eae 100644
--- a/lib/Transforms/Scalar/IndVarSimplify.cpp
+++ b/lib/Transforms/Scalar/IndVarSimplify.cpp
@@ -465,17 +465,6 @@
// Compute the final addrec to expand into code.
SCEVHandle AR = IU->getReplacementExpr(*UI);
- // FIXME: It is an extremely bad idea to indvar substitute anything more
- // complex than affine induction variables. Doing so will put expensive
- // polynomial evaluations inside of the loop, and the str reduction pass
- // currently can only reduce affine polynomials. For now just disable
- // indvar subst on anything more complex than an affine addrec, unless
- // it can be expanded to a trivial value.
- if (!Stride->isLoopInvariant(L) &&
- !isa<SCEVConstant>(AR) &&
- L->contains(User->getParent()))
- continue;
-
Value *NewVal = 0;
if (AR->isLoopInvariant(L)) {
BasicBlock::iterator I = Rewriter.getInsertionPoint();
@@ -487,6 +476,15 @@
Rewriter.setInsertionPoint(I);
++NumReplaced;
} else {
+ // FIXME: It is an extremely bad idea to indvar substitute anything more
+ // complex than affine induction variables. Doing so will put expensive
+ // polynomial evaluations inside of the loop, and the str reduction pass
+ // currently can only reduce affine polynomials. For now just disable
+ // indvar subst on anything more complex than an affine addrec, unless
+ // it can be expanded to a trivial value.
+ if (!Stride->isLoopInvariant(L))
+ continue;
+
const Type *IVTy = Offset->getType();
const Type *UseTy = Op->getType();
@@ -520,7 +518,7 @@
// induction variable, still in the canonical induction variable's
// type, so that all expanded arithmetic is done in the same type.
SCEVHandle NewAR = SE->getAddRecExpr(SE->getIntegerSCEV(0, LargestType),
- PromotedStride, L);
+ PromotedStride, L);
// Add the PromotedOffset as a separate step, because it may not be
// loop-invariant.
NewAR = SE->getAddExpr(NewAR, PromotedOffset);