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Miscellaneous clean-ups based on Evan's feedback:

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- Cleaned up how the prologue-epilogue inserter loops over the instructions.
- Instead of restarting the processing of an instruction if we remove an
  implicit kill, just update the end iterator and make sure that the iterator
  isn't incremented.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@47870 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Bill Wendling
2008-03-03 23:57:28 +00:00
parent 220a823f8d
commit 405abffd5e
2 changed files with 80 additions and 66 deletions
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96
lib/CodeGen/PrologEpilogInserter.cpp
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@@ -517,53 +517,63 @@ void PEI::replaceFrameIndices(MachineFunction &Fn) {
for (MachineBasicBlock::iterator I = BB->begin(); I != BB->end(); ) {
MachineInstr *MI = I;
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
// Remember how much SP has been adjustment to create the call frame.
int Size = I->getOperand(0).getImm();
if ((!StackGrowsDown && I->getOpcode() == FrameSetupOpcode) ||
(StackGrowsDown && I->getOpcode() == FrameDestroyOpcode))
Size = -Size;
SPAdj += Size;
MachineBasicBlock::iterator PrevI = prior(I);
TRI.eliminateCallFramePseudoInstr(Fn, *BB, I);
// Visit the instructions created by eliminateCallFramePseudoInstr().
I = next(PrevI);
MI = NULL;
} else if (I->getOpcode() == TargetInstrInfo::DECLARE) {
if (I->getOpcode() == TargetInstrInfo::DECLARE) {
// Ignore it.
++I;
} else {
bool DoIncr = true;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
if (MI->getOperand(i).isFrameIndex()) {
// Some instructions (e.g. inline asm instructions) can have
// multiple frame indices and/or cause eliminateFrameIndex to insert
// more than one instruction. We need the register scavenger to go
// through all of these instructions so that it can update its
// register information. We keep the iterator at the point before
// insertion so that we can revisit them in full.
bool AtBeginning = (I == BB->begin());
if (!AtBeginning) --I;
// If this instruction has a FrameIndex operand, we need to use that
// target machine register info object to eliminate it.
TRI.eliminateFrameIndex(MI, SPAdj, RS);
// Reset the iterator if we were at the beginning of the BB.
if (AtBeginning) {
I = BB->begin();
DoIncr = false;
}
MI = 0;
break;
}
if (DoIncr) ++I;
continue;
}
if (I->getOpcode() == FrameSetupOpcode ||
I->getOpcode() == FrameDestroyOpcode) {
// Remember how much SP has been adjusted to create the call
// frame.
int Size = I->getOperand(0).getImm();
if ((!StackGrowsDown && I->getOpcode() == FrameSetupOpcode) ||
(StackGrowsDown && I->getOpcode() == FrameDestroyOpcode))
Size = -Size;
SPAdj += Size;
MachineBasicBlock::iterator PrevI = prior(I);
TRI.eliminateCallFramePseudoInstr(Fn, *BB, I);
// Visit the instructions created by eliminateCallFramePseudoInstr().
I = next(PrevI);
continue;
}
bool DoIncr = true;
for (unsigned i = 0, e = MI->getNumOperands(); i != e; ++i)
if (MI->getOperand(i).isFrameIndex()) {
// Some instructions (e.g. inline asm instructions) can have
// multiple frame indices and/or cause eliminateFrameIndex
// to insert more than one instruction. We need the register
// scavenger to go through all of these instructions so that
// it can update its register information. We keep the
// iterator at the point before insertion so that we can
// revisit them in full.
bool AtBeginning = (I == BB->begin());
if (!AtBeginning) --I;
// If this instruction has a FrameIndex operand, we need to
// use that target machine register info object to eliminate
// it.
TRI.eliminateFrameIndex(MI, SPAdj, RS);
// Reset the iterator if we were at the beginning of the BB.
if (AtBeginning) {
I = BB->begin();
DoIncr = false;
}
MI = 0;
break;
}
if (DoIncr) ++I;
// Update register states.
if (RS && MI) RS->forward(MI);
}