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-rw-r--r--llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp11
1 files changed, 5 insertions, 6 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
index 75677079e37..f22e8a69bdb 100644
--- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp
@@ -1048,17 +1048,16 @@ void Cost::RateRegister(const SCEV *Reg,
const Loop *L,
ScalarEvolution &SE, DominatorTree &DT) {
if (const SCEVAddRecExpr *AR = dyn_cast<SCEVAddRecExpr>(Reg)) {
- // If this is an addrec for another loop, don't second-guess its addrec phi
- // nodes. LSR isn't currently smart enough to reason about more than one
- // loop at a time. LSR has already run on inner loops, will not run on outer
- // loops, and cannot be expected to change sibling loops.
+ // If this is an addrec for another loop, it should be an invariant
+ // with respect to L since L is the innermost loop (at least
+ // for now LSR only handles innermost loops).
if (AR->getLoop() != L) {
// If the AddRec exists, consider it's register free and leave it alone.
if (isExistingPhi(AR, SE))
return;
- // Otherwise, do not consider this formula at all.
- Lose();
+ // Otherwise, it will be an invariant with respect to Loop L.
+ ++NumRegs;
return;
}
AddRecCost += 1; /// TODO: This should be a function of the stride.
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