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Fix a bug where splitting cause some unnecessary spilling. 

llvm-svn: 44482
This commit is contained in:
Evan Cheng 2007-12-01 04:42:39 +00:00
parent 7f09c88977
commit 388f6f51a0
1 changed files with 12 additions and 2 deletions
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14
llvm/lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -995,9 +995,9 @@ rewriteInstructionsForSpills(const LiveInterval &li, bool TrySplit,
if (VNI)
HasKill = anyKillInMBBAfterIdx(li, VNI, MBB, getDefIndex(index));
}
std::map<unsigned, std::vector<SRInfo> >::iterator SII =
SpillIdxes.find(MBBId);
if (!HasKill) {
std::map<unsigned, std::vector<SRInfo> >::iterator SII =
SpillIdxes.find(MBBId);
if (SII == SpillIdxes.end()) {
std::vector<SRInfo> S;
S.push_back(SRInfo(index, NewVReg, true));
@ -1013,6 +1013,16 @@ rewriteInstructionsForSpills(const LiveInterval &li, bool TrySplit,
Info.canFold = !HasUse;
}
SpillMBBs.set(MBBId);
} else if (SII != SpillIdxes.end() &&
SII->second.back().vreg == NewVReg &&
(int)index > SII->second.back().index) {
// There is an earlier def that's not killed (must be two-address).
// The spill is no longer needed.
SII->second.pop_back();
if (SII->second.empty()) {
SpillIdxes.erase(MBBId);
SpillMBBs.reset(MBBId);
}
}
}
}