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Only ignore <undef> use operands, keep the <def,undef> ops.

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Def operands may also have an <undef> flag, but that just means that a
sub-register redef doesn't actually read the super-register. For physical
registers, it has no meaning.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@130714 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen 2011-05-02 20:06:28 +00:00
parent 8ce864e324
commit 2048e4ab7f
1 changed files with 4 additions and 1 deletions
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5
lib/CodeGen/RegisterScavenging.cpp
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@ -154,13 +154,16 @@ void RegScavenger::forward() {
BitVector DeadRegs(NumPhysRegs);
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i) {
const MachineOperand &MO = MI->getOperand(i);
if (!MO.isReg() || MO.isUndef())
if (!MO.isReg())
continue;
unsigned Reg = MO.getReg();
if (!Reg || isReserved(Reg))
continue;
if (MO.isUse()) {
// Ignore undef uses.
if (MO.isUndef())
continue;
// Two-address operands implicitly kill.
if (!isPred && (MO.isKill() || MI->isRegTiedToDefOperand(i)))
addRegWithSubRegs(KillRegs, Reg);