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Try fold re-materialized load instructions into its uses.

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@41598 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Evan Cheng 2007-08-30 05:53:02 +00:00
parent 35b35c5c32
commit 34c2a9f57c
1 changed files with 22 additions and 11 deletions
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33
lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -236,10 +236,17 @@ bool LiveIntervals::isReMaterializable(const LiveInterval &li,
return true;
}
/// tryFoldMemoryOperand - Attempts to fold either a spill / restore from
/// slot / to reg or any rematerialized load into ith operand of specified
/// MI. If it is successul, MI is updated with the newly created MI and
/// returns true.
bool LiveIntervals::tryFoldMemoryOperand(MachineInstr* &MI, VirtRegMap &vrm,
unsigned index, unsigned i,
bool isSS, MachineInstr *DefMI,
int slot, unsigned reg) {
MachineInstr *fmi = mri_->foldMemoryOperand(MI, i, slot);
MachineInstr *fmi = isSS
? mri_->foldMemoryOperand(MI, i, slot)
: mri_->foldMemoryOperand(MI, i, DefMI);
if (fmi) {
// Attempt to fold the memory reference into the instruction. If
// we can do this, we don't need to insert spill code.
@ -340,6 +347,8 @@ addIntervalsForSpills(const LiveInterval &li, VirtRegMap &vrm, unsigned reg) {
bool CanDelete = ReMatDelete[I->valno->id];
int LdSlot = 0;
bool isLoadSS = DefIsReMat && tii_->isLoadFromStackSlot(DefMI, LdSlot);
bool isLoad = isLoadSS ||
(DefIsReMat && (DefMI->getInstrDescriptor()->Flags & M_LOAD_FLAG));
unsigned index = getBaseIndex(I->start);
unsigned end = getBaseIndex(I->end-1) + InstrSlots::NUM;
for (; index != end; index += InstrSlots::NUM) {
@ -362,20 +371,22 @@ addIntervalsForSpills(const LiveInterval &li, VirtRegMap &vrm, unsigned reg) {
RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
break;
} else if (tryFoldMemoryOperand(MI, vrm, index, i, slot, li.reg))
} else if (tryFoldMemoryOperand(MI, vrm, index, i, true,
DefMI, slot, li.reg)) {
// Folding the load/store can completely change the instruction
// in unpredictable ways, rescan it from the beginning.
goto RestartInstruction;
} else if (isLoadSS &&
tryFoldMemoryOperand(MI, vrm, index, i, LdSlot, li.reg)){
// FIXME: Other rematerializable loads can be folded as well.
// Folding the load/store can completely change the
// instruction in unpredictable ways, rescan it from
// the beginning.
goto RestartInstruction;
}
}
} else if (isLoad &&
tryFoldMemoryOperand(MI, vrm, index, i, isLoadSS,
DefMI, LdSlot, li.reg))
// Folding the load/store can completely change the
// instruction in unpredictable ways, rescan it from
// the beginning.
goto RestartInstruction;
} else {
if (tryFoldMemoryOperand(MI, vrm, index, i, slot, li.reg))
if (tryFoldMemoryOperand(MI, vrm, index, i, true, DefMI,
slot, li.reg))
// Folding the load/store can completely change the instruction in
// unpredictable ways, rescan it from the beginning.
goto RestartInstruction;