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Update live intervals more accurately for PHI elim. This slightly reduces 

the live intervals for some registers.

llvm-svn: 15125
This commit is contained in:
Chris Lattner 2004-07-23 05:27:43 +00:00
parent b549420cd0
commit 2d75978bc6
1 changed files with 6 additions and 10 deletions
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16
llvm/lib/CodeGen/PHIElimination.cpp
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@ -131,18 +131,9 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) {
std::pair<LiveVariables::killed_iterator, LiveVariables::killed_iterator>
RKs = LV->killed_range(MPhi);
std::vector<std::pair<MachineInstr*, unsigned> > Range;
if (RKs.first != RKs.second) {
// Copy the range into a vector...
Range.assign(RKs.first, RKs.second);
// Delete the range...
if (RKs.first != RKs.second) // Delete the range.
LV->removeVirtualRegistersKilled(RKs.first, RKs.second);
// Add all of the kills back, which will update the appropriate info...
for (unsigned i = 0, e = Range.size(); i != e; ++i)
LV->addVirtualRegisterKilled(Range[i].second, PHICopy);
}
RKs = LV->dead_range(MPhi);
if (RKs.first != RKs.second) {
// Works as above...
@ -252,6 +243,11 @@ bool PNE::EliminatePHINodes(MachineFunction &MF, MachineBasicBlock &MBB) {
if (!ValueIsLive) {
MachineBasicBlock::iterator Prev = prior(I);
LV->addVirtualRegisterKilled(SrcReg, Prev);
// This vreg no longer lives all of the way through opBlock.
unsigned opBlockNum = opBlock.getNumber();
if (opBlockNum < InRegVI.AliveBlocks.size())
InRegVI.AliveBlocks[opBlockNum] = false;
}
}
}