From f143b79b78d1d244809fa59320f2af2edf4e1a86 Mon Sep 17 00:00:00 2001 From: Andrew Trick Date: Tue, 4 Oct 2011 03:50:44 +0000 Subject: LSR should avoid redundant edge splitting. This handles the case in which LSR rewrites an IV user that is a phi and splits critical edges originating from a switch. Fixes LSR is not splitting edges "nicely" git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@141059 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Scalar/LoopStrengthReduce.cpp | 4 +++- lib/Transforms/Utils/BreakCriticalEdges.cpp | 5 +++-- 2 files changed, 6 insertions(+), 3 deletions(-) (limited to 'lib') diff --git a/lib/Transforms/Scalar/LoopStrengthReduce.cpp b/lib/Transforms/Scalar/LoopStrengthReduce.cpp index 7b1a340156..4b6c55e162 100644 --- a/lib/Transforms/Scalar/LoopStrengthReduce.cpp +++ b/lib/Transforms/Scalar/LoopStrengthReduce.cpp @@ -3677,7 +3677,9 @@ void LSRInstance::RewriteForPHI(PHINode *PN, // Split the critical edge. BasicBlock *NewBB = 0; if (!Parent->isLandingPad()) { - NewBB = SplitCriticalEdge(BB, Parent, P); + NewBB = SplitCriticalEdge(BB, Parent, P, + /*MergeIdenticalEdges=*/true, + /*DontDeleteUselessPhis=*/true); } else { SmallVector NewBBs; SplitLandingPadPredecessors(Parent, BB, "", "", P, NewBBs); diff --git a/lib/Transforms/Utils/BreakCriticalEdges.cpp b/lib/Transforms/Utils/BreakCriticalEdges.cpp index 4648f49645..c052910881 100644 --- a/lib/Transforms/Utils/BreakCriticalEdges.cpp +++ b/lib/Transforms/Utils/BreakCriticalEdges.cpp @@ -167,7 +167,8 @@ static void CreatePHIsForSplitLoopExit(SmallVectorImpl &Preds, /// to. /// BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, - Pass *P, bool MergeIdenticalEdges) { + Pass *P, bool MergeIdenticalEdges, + bool DontDeleteUselessPhis) { if (!isCriticalEdge(TI, SuccNum, MergeIdenticalEdges)) return 0; assert(!isa(TI) && @@ -224,7 +225,7 @@ BasicBlock *llvm::SplitCriticalEdge(TerminatorInst *TI, unsigned SuccNum, if (TI->getSuccessor(i) != DestBB) continue; // Remove an entry for TIBB from DestBB phi nodes. - DestBB->removePredecessor(TIBB); + DestBB->removePredecessor(TIBB, DontDeleteUselessPhis); // We found another edge to DestBB, go to NewBB instead. TI->setSuccessor(i, NewBB); -- cgit v1.2.3