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Pre-alloc splitting needs to be more careful to avoid inserting spills/restores

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between call frame setup/restore points.  Unfortunately, this regresses 
code size a bit, but at least it's correct now!


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63837 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Owen Anderson 2009-02-05 05:58:41 +00:00
parent ce459b1e28
commit 5734c94ec2
1 changed files with 72 additions and 22 deletions
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94
lib/CodeGen/PreAllocSplitting.cpp
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@ -228,28 +228,52 @@ PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI,
++MII;
unsigned Index = LIs->getInstructionIndex(MII);
unsigned Gap = LIs->findGapBeforeInstr(Index);
if (Gap) {
// We can't insert the spill between the barrier (a call), and its
// corresponding call frame setup/teardown.
if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) {
bool reachedBarrier = false;
do {
if (MII == EndPt) {
reachedBarrier = true;
break;
}
++MII;
} while (MII->getOpcode() != TRI->getCallFrameDestroyOpcode());
if (reachedBarrier) break;
} else if (Gap) {
Pt = MII;
SpillIndex = Gap;
break;
// We can't insert the spill between the barrier (a call), and its
// corresponding call frame setup.
} else if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode() &&
MII == MachineBasicBlock::iterator(MI))
break;
}
} while (MII != EndPt);
} else {
MachineBasicBlock::iterator MII = MI;
MachineBasicBlock::iterator EndPt = DefMI
? MachineBasicBlock::iterator(DefMI) : MBB->begin();
// We can't insert the spill between the barrier (a call), and its
// corresponding call frame setup.
if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) --MII;
while (MII != EndPt && !RefsInMBB.count(MII)) {
unsigned Index = LIs->getInstructionIndex(MII);
if (LIs->hasGapBeforeInstr(Index)) {
// We can't insert the spill between the barrier (a call), and its
// corresponding call frame setup.
if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) {
--MII;
continue;
} if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {
bool reachedBarrier = false;
while (MII->getOpcode() != TRI->getCallFrameSetupOpcode()) {
--MII;
if (MII == EndPt) {
reachedBarrier = true;
break;
}
}
if (reachedBarrier) break;
else continue;
} else if (LIs->hasGapBeforeInstr(Index)) {
Pt = MII;
SpillIndex = LIs->findGapBeforeInstr(Index, true);
}
@ -283,25 +307,32 @@ PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI,
do {
unsigned Index = LIs->getInstructionIndex(MII);
unsigned Gap = LIs->findGapBeforeInstr(Index);
if (Gap) {
Pt = MII;
RestoreIndex = Gap;
break;
// We can't insert a restore between the barrier (a call) and its
// corresponding call frame teardown.
} else if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode() &&
prior(MII) == MachineBasicBlock::iterator(MI))
if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {
bool reachedBarrier = false;
while (MII->getOpcode() != TRI->getCallFrameSetupOpcode()) {
--MII;
if (MII == EndPt) {
reachedBarrier = true;
break;
}
}
if (reachedBarrier) break;
else continue;
} else if (Gap) {
Pt = MII;
RestoreIndex = Gap;
break;
}
--MII;
} while (MII != EndPt);
} else {
MachineBasicBlock::iterator MII = MI;
MII = ++MII;
// We can't insert a restore between the barrier (a call) and its
// corresponding call frame teardown.
if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode())
++MII;
// FIXME: Limit the number of instructions to examine to reduce
// compile time?
@ -310,10 +341,29 @@ PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI,
if (Index > LastIdx)
break;
unsigned Gap = LIs->findGapBeforeInstr(Index);
if (Gap) {
// We can't insert a restore between the barrier (a call) and its
// corresponding call frame teardown.
if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {
++MII;
continue;
} else if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) {
bool reachedBarrier = false;
do {
if (MII == MBB->getFirstTerminator() || RefsInMBB.count(MII)) {
reachedBarrier = true;
break;
}
++MII;
} while (MII->getOpcode() != TRI->getCallFrameDestroyOpcode());
if (reachedBarrier) break;
} else if (Gap) {
Pt = MII;
RestoreIndex = Gap;
}
if (RefsInMBB.count(MII))
break;
++MII;