Author: evancheng
Date: Thu Aug 30 00:53:02 2007
New Revision: 41598
URL: http://llvm.org/viewvc/llvm-project?rev=41598&view=rev
Log:
Try fold re-materialized load instructions into its uses.
Modified:
llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
Modified: llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp
URL:
http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp?rev=41598&r1=41597&r2=41598&view=diff
==============================================================================
--- llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp (original)
+++ llvm/trunk/lib/CodeGen/LiveIntervalAnalysis.cpp Thu Aug 30 00:53:02 2007
@@ -236,10 +236,17 @@
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 @@
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 @@
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;
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