Only trim a live interval if the register is not used after the PHI node.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@54421 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2008-08-06 18:36:17 +00:00
parent 788d04152a
commit 9b49120408

View File

@ -896,13 +896,16 @@ bool StrongPHIElimination::runOnMachineFunction(MachineFunction &Fn) {
}
} else {
// Trim live intervals of input registers. They are no longer live into
// this block.
// this block if they died after the PHI. If they lived after it, don't
// trim them because they might have other legitimate uses.
for (unsigned i = 1; i < PInstr->getNumOperands(); i += 2) {
unsigned reg = PInstr->getOperand(i).getReg();
MachineBasicBlock* MBB = PInstr->getOperand(i+1).getMBB();
LiveInterval& InputI = LI.getInterval(reg);
if (MBB != PInstr->getParent() &&
InputI.liveAt(LI.getMBBStartIdx(PInstr->getParent())))
InputI.liveAt(LI.getMBBStartIdx(PInstr->getParent())) &&
InputI.expiredAt(LI.getInstructionIndex(PInstr) +
LiveIntervals::InstrSlots::NUM))
InputI.removeRange(LI.getMBBStartIdx(PInstr->getParent()),
LI.getInstructionIndex(PInstr),
true);