diff options
Diffstat (limited to 'llvm/lib/Transforms')
| -rw-r--r-- | llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp index f22e8a69bdb..75677079e37 100644 --- a/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/llvm/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -1048,16 +1048,17 @@ 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, 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 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 (AR->getLoop() != L) { // If the AddRec exists, consider it's register free and leave it alone. if (isExistingPhi(AR, SE)) return; - // Otherwise, it will be an invariant with respect to Loop L. - ++NumRegs; + // Otherwise, do not consider this formula at all. + Lose(); return; } AddRecCost += 1; /// TODO: This should be a function of the stride. |
