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| author | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-08-03 20:10:24 +0000 |
|---|---|---|
| committer | Jakob Stoklund Olesen <stoklund@2pi.dk> | 2012-08-03 20:10:24 +0000 |
| commit | 0ab7103e06ee1da7bde5b196a68be77ab49a005d (patch) | |
| tree | b43967a87c6c80bd83fdcfcc8bd2c48da2dd95d8 /lib/CodeGen/RegisterCoalescer.cpp | |
| parent | 09a887345f283f3ffb46a36e78ca761026ab0cf2 (diff) | |
| download | llvm-0ab7103e06ee1da7bde5b196a68be77ab49a005d.tar.gz llvm-0ab7103e06ee1da7bde5b196a68be77ab49a005d.tar.bz2 llvm-0ab7103e06ee1da7bde5b196a68be77ab49a005d.tar.xz | |
Make the hasPHIKills flag a computed property.
The VNInfo::HAS_PHI_KILL is only half supported. We precompute it in
LiveIntervalAnalysis, but it isn't properly updated by live range
splitting and functions like shrinkToUses().
It is only used in one place: RegisterCoalescer::removeCopyByCommutingDef().
This patch changes that function to use a new LiveIntervals::hasPHIKill()
function that computes the flag for a given value number.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@161254 91177308-0d34-0410-b5e6-96231b3b80d8
Diffstat (limited to 'lib/CodeGen/RegisterCoalescer.cpp')
| -rw-r--r-- | lib/CodeGen/RegisterCoalescer.cpp | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/lib/CodeGen/RegisterCoalescer.cpp b/lib/CodeGen/RegisterCoalescer.cpp index 349fcde5ef..ebac8f14bc 100644 --- a/lib/CodeGen/RegisterCoalescer.cpp +++ b/lib/CodeGen/RegisterCoalescer.cpp @@ -494,6 +494,11 @@ bool RegisterCoalescer::hasOtherReachingDefs(LiveInterval &IntA, LiveInterval &IntB, VNInfo *AValNo, VNInfo *BValNo) { + // If AValNo has PHI kills, conservatively assume that IntB defs can reach + // the PHI values. + if (LIS->hasPHIKill(IntA, AValNo)) + return true; + for (LiveInterval::iterator AI = IntA.begin(), AE = IntA.end(); AI != AE; ++AI) { if (AI->valno != AValNo) continue; @@ -558,10 +563,7 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP, // AValNo is the value number in A that defines the copy, A3 in the example. VNInfo *AValNo = IntA.getVNInfoAt(CopyIdx.getRegSlot(true)); assert(AValNo && "COPY source not live"); - - // If other defs can reach uses of this def, then it's not safe to perform - // the optimization. - if (AValNo->isPHIDef() || AValNo->isUnused() || AValNo->hasPHIKill()) + if (AValNo->isPHIDef() || AValNo->isUnused()) return false; MachineInstr *DefMI = LIS->getInstructionFromIndex(AValNo->def); if (!DefMI) |