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Allow missing kill flags on an untied operand of a two-address instruction when 

the operand uses the same register as a tied operand:

  %r1 = add %r1, %r1

If add were a three-address instruction, kill flags would be required on at
least one of the uses. Since it is a two-address instruction, the tied use
operand must not have a kill flag.

This change makes the kill flag on the untied use operand optional.

llvm-svn: 122082
This commit is contained in:
Jakob Stoklund Olesen 2010-12-17 19:18:41 +00:00
parent 213de04d75
commit a043b62870
1 changed files with 6 additions and 1 deletions
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7
llvm/lib/CodeGen/MachineVerifier.cpp
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@ -625,7 +625,12 @@ MachineVerifier::visitMachineOperand(const MachineOperand *MO, unsigned MONum) {
*OS << UseIdx << " is not live in " << LI << '\n';
}
// Verify isKill == LI.killedAt.
if (!MI->isRegTiedToDefOperand(MONum)) {
// Two-address instrs don't have kill flags on the tied operands, and
// we even allow
// %r1 = add %r1, %r1
// without a kill flag on the untied operand.
// MI->findRegisterUseOperandIdx finds the first operand using reg.
if (!MI->isRegTiedToDefOperand(MI->findRegisterUseOperandIdx(Reg))) {
// MI could kill register without a kill flag on MO.
bool miKill = MI->killsRegister(Reg);
bool liKill = LI.killedAt(UseIdx.getDefIndex());