EXTRACT_SUBREG coalescing support. The coalescer now treats EXTRACT_SUBREG like

(almost) a register copy. However, it always coalesced to the register of the
RHS (the super-register). All uses of the result of a EXTRACT_SUBREG are sub-
register uses which adds subtle complications to load folding, spiller rewrite,
etc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@42899 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng
2007-10-12 08:50:34 +00:00
parent 10136e7c7f
commit 32dfbeada7
12 changed files with 422 additions and 248 deletions

View File

@ -220,6 +220,24 @@ int MachineInstr::findFirstPredOperandIdx() const {
return -1;
}
/// isRegReDefinedByTwoAddr - Returns true if the Reg re-definition is due
/// to two addr elimination.
bool MachineInstr::isRegReDefinedByTwoAddr(unsigned Reg) const {
const TargetInstrDescriptor *TID = getInstrDescriptor();
for (unsigned i = 0, e = getNumOperands(); i != e; ++i) {
const MachineOperand &MO1 = getOperand(i);
if (MO1.isRegister() && MO1.isDef() && MO1.getReg() == Reg) {
for (unsigned j = i+1; j < e; ++j) {
const MachineOperand &MO2 = getOperand(j);
if (MO2.isRegister() && MO2.isUse() && MO2.getReg() == Reg &&
TID->getOperandConstraint(j, TOI::TIED_TO) == (int)i)
return true;
}
}
}
return false;
}
/// copyKillDeadInfo - Copies kill / dead operand properties from MI.
///
void MachineInstr::copyKillDeadInfo(const MachineInstr *MI) {