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Patch r153892 for PR11861 apparently broke an external project (see PR12493).

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This patch restores TwoAddressInstructionPass's pre-r153892 behaviour when
rescheduling instructions in TryInstructionTransform. Hopefully this will fix
PR12493. To refix PR11861, lowering of INSERT_SUBREGS is deferred until after
the copy that unties the operands is emitted (this seems to be a more
appropriate fix for that issue anyway).



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@154338 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Lang Hames 2012-04-09 20:17:30 +00:00
parent 96b66d65c2
commit f31ceaf8b7
1 changed files with 17 additions and 16 deletions
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33
lib/CodeGen/TwoAddressInstructionPass.cpp
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@ -1183,8 +1183,9 @@ TwoAddressInstructionPass::RescheduleKillAboveMI(MachineBasicBlock *MBB,
/// TryInstructionTransform - For the case where an instruction has a single
/// pair of tied register operands, attempt some transformations that may
/// either eliminate the tied operands or improve the opportunities for
/// coalescing away the register copy. Returns true if the tied operands
/// are eliminated altogether.
/// coalescing away the register copy. Returns true if no copy needs to be
/// inserted to untie mi's operands (either because they were untied, or
/// because mi was rescheduled, and will be visited again later).
bool TwoAddressInstructionPass::
TryInstructionTransform(MachineBasicBlock::iterator &mi,
MachineBasicBlock::iterator &nmi,
@ -1248,7 +1249,7 @@ TryInstructionTransform(MachineBasicBlock::iterator &mi,
// re-schedule this MI below it.
if (RescheduleMIBelowKill(mbbi, mi, nmi, regB)) {
++NumReSchedDowns;
return false;
return true;
}
if (TargetRegisterInfo::isVirtualRegister(regA))
@ -1270,7 +1271,7 @@ TryInstructionTransform(MachineBasicBlock::iterator &mi,
// re-schedule it before this MI if it's legal.
if (RescheduleKillAboveMI(mbbi, mi, nmi, regB)) {
++NumReSchedUps;
return false;
return true;
}
// If this is an instruction with a load folded into it, try unfolding
@ -1594,19 +1595,19 @@ bool TwoAddressInstructionPass::runOnMachineFunction(MachineFunction &MF) {
MadeChange = true;
DEBUG(dbgs() << "\t\trewrite to:\t" << *mi);
}
// Rewrite INSERT_SUBREG as COPY now that we no longer need SSA form.
if (mi->isInsertSubreg()) {
// From %reg = INSERT_SUBREG %reg, %subreg, subidx
// To %reg:subidx = COPY %subreg
unsigned SubIdx = mi->getOperand(3).getImm();
mi->RemoveOperand(3);
assert(mi->getOperand(0).getSubReg() == 0 && "Unexpected subreg idx");
mi->getOperand(0).setSubReg(SubIdx);
mi->RemoveOperand(1);
mi->setDesc(TII->get(TargetOpcode::COPY));
DEBUG(dbgs() << "\t\tconvert to:\t" << *mi);
// Rewrite INSERT_SUBREG as COPY now that we no longer need SSA form.
if (mi->isInsertSubreg()) {
// From %reg = INSERT_SUBREG %reg, %subreg, subidx
// To %reg:subidx = COPY %subreg
unsigned SubIdx = mi->getOperand(3).getImm();
mi->RemoveOperand(3);
assert(mi->getOperand(0).getSubReg() == 0 && "Unexpected subreg idx");
mi->getOperand(0).setSubReg(SubIdx);
mi->RemoveOperand(1);
mi->setDesc(TII->get(TargetOpcode::COPY));
DEBUG(dbgs() << "\t\tconvert to:\t" << *mi);
}
}
// Clear TiedOperands here instead of at the top of the loop