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Don't use an expensive check for two-address-ness when we have the information sitting around to determine it much more quickly,

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This speeds up the local register allocator from 0.37s to 0.31s on instcombine.

llvm-svn: 53359
This commit is contained in:
Owen Anderson 2008-07-09 21:15:10 +00:00
parent 36a38a5ba1
commit 50a64de51e
1 changed files with 13 additions and 2 deletions
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15
lib/CodeGen/RegAllocLocal.cpp
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@ -585,13 +585,24 @@ void RALocal::ComputeLocalLiveness(MachineBasicBlock& MBB) {
// Defs others than 2-addr redefs _do_ trigger flag changes:
// - A def followed by a def is dead
// - A use followed by a def is a kill
if (MO.isReg() && MO.getReg() && MO.isDef() &&
!I->isRegReDefinedByTwoAddr(MO.getReg())) {
if (MO.isReg() && MO.getReg() && MO.isDef()) {
std::map<unsigned, std::pair<MachineInstr*, unsigned> >::iterator
last = LastUseDef.find(MO.getReg());
if (last != LastUseDef.end()) {
// If this is a two address instr, then we don't mark the def
// as killing the use.
if (last->second.first == I &&
I->getDesc().getOperandConstraint(last->second.second,
TOI::TIED_TO) == (signed)i) {
LastUseDef[MO.getReg()] = std::make_pair(I, i);
continue;
}
MachineOperand& lastUD =
last->second.first->getOperand(last->second.second);
if (lastUD.isDef())
lastUD.setIsDead(true);
else if (lastUD.isUse())