diff options
| -rw-r--r-- | lib/Transforms/Scalar/LoopStrengthReduce.cpp | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 26fc03b18b..d03b86a7e9 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -83,6 +83,12 @@ cl::opt<bool> EnableNested( cl::opt<bool> EnableRetry( "enable-lsr-retry", cl::Hidden, cl::desc("Enable LSR retry")); + +// Temporary flag to cleanup congruent phis after LSR phi expansion. +// It's currently disabled until we can determine whether it's truly useful or +// not. The flag should be removed after the v3.0 release. +cl::opt<bool> EnablePhiElim( + "enable-lsr-phielim", cl::Hidden, cl::desc("Enable LSR phi elimination")); } namespace { @@ -3816,6 +3822,14 @@ LSRInstance::LSRInstance(const TargetLowering *tli, Loop *l, Pass *P) // Skip nested loops until we can model them better with formulae. if (!EnableNested && !L->empty()) { + + if (EnablePhiElim) { + // Remove any extra phis created by processing inner loops. + SmallVector<WeakVH, 16> DeadInsts; + SCEVExpander Rewriter(SE, "lsr"); + Changed |= Rewriter.replaceCongruentIVs(L, &DT, DeadInsts); + Changed |= DeleteTriviallyDeadInstructions(DeadInsts); + } DEBUG(dbgs() << "LSR skipping outer loop " << *L << "\n"); return; } @@ -3861,6 +3875,14 @@ LSRInstance::LSRInstance(const TargetLowering *tli, Loop *l, Pass *P) // Now that we've decided what we want, make it so. ImplementSolution(Solution, P); + + if (EnablePhiElim) { + // Remove any extra phis created by processing inner loops. + SmallVector<WeakVH, 16> DeadInsts; + SCEVExpander Rewriter(SE, "lsr"); + Changed |= Rewriter.replaceCongruentIVs(L, &DT, DeadInsts); + Changed |= DeleteTriviallyDeadInstructions(DeadInsts); + } } void LSRInstance::print_factors_and_types(raw_ostream &OS) const { |