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RemoveCopyByCommutingDef doesn't need hasPHIKill().

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Instead, let HasOtherReachingDefs() test for defs in B that overlap any
phi-defs in A as well.  This test is slightly different, but almost
identical.

A perfectly precise test would only check those phi-defs in A that are
reachable from AValNo.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@139782 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-09-15 05:03:50 +00:00
parent 4ea24e993f
commit de07abe35d
1 changed files with 8 additions and 8 deletions
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16
lib/CodeGen/RegisterCoalescer.cpp
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@ -566,14 +566,16 @@ bool RegisterCoalescer::AdjustCopiesBackFrom(const CoalescerPair &CP,
}
/// HasOtherReachingDefs - Return true if there are definitions of IntB
/// other than BValNo val# that can reach uses of AValno val# of IntA.
/// other than BValNo val# that can reach uses of AValno val# of IntA, or any
/// of its phis.
bool RegisterCoalescer::HasOtherReachingDefs(LiveInterval &IntA,
LiveInterval &IntB,
VNInfo *AValNo,
VNInfo *BValNo) {
LiveInterval &IntB,
VNInfo *AValNo,
VNInfo *BValNo) {
for (LiveInterval::iterator AI = IntA.begin(), AE = IntA.end();
AI != AE; ++AI) {
if (AI->valno != AValNo) continue;
if (AI->valno != AValNo && !AI->valno->isPHIDef())
continue;
LiveInterval::Ranges::iterator BI =
std::upper_bound(IntB.ranges.begin(), IntB.ranges.end(), AI->start);
if (BI != IntB.ranges.begin())
@ -645,9 +647,7 @@ bool RegisterCoalescer::RemoveCopyByCommutingDef(const CoalescerPair &CP,
VNInfo *AValNo = IntA.getVNInfoAt(CopyIdx.getUseIndex());
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)