From b913863a95a70fcfe2c5b144c574307dc3d29d88 Mon Sep 17 00:00:00 2001 From: Bob Wilson Date: Wed, 21 Apr 2010 18:39:03 +0000 Subject: [PATCH] Fix a performance problem with the new SSAUpdater. This showed up in the GCCAS time for MultiSource/Benchmarks/ASCI_Purple/SMG2000. git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@102009 91177308-0d34-0410-b5e6-96231b3b80d8 --- lib/Transforms/Utils/SSAUpdater.cpp | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/lib/Transforms/Utils/SSAUpdater.cpp b/lib/Transforms/Utils/SSAUpdater.cpp index d491cbb9155..25d50dbf2a8 100644 --- a/lib/Transforms/Utils/SSAUpdater.cpp +++ b/lib/Transforms/Utils/SSAUpdater.cpp @@ -529,9 +529,15 @@ void SSAUpdater::FindAvailableVals(BlockListTy *BlockList) { E = BlockList->rend(); I != E; ++I) { BBInfo *Info = *I; - // Check if this block contains a newly added PHI. - if (Info->DefBB != Info) + if (Info->DefBB != Info) { + // Record the available value at join nodes to speed up subsequent + // uses of this SSAUpdater for the same value. + if (Info->NumPreds > 1) + AvailableVals[Info->BB] = Info->DefBB->AvailableVal; continue; + } + + // Check if this block contains a newly added PHI. PHINode *PHI = dyn_cast(Info->AvailableVal); if (!PHI || PHI->getNumIncomingValues() == Info->NumPreds) continue; -- 2.34.1