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Remove the "fast" cases for spill and restore point determination, as these were subtlely wrong in obscure cases. Patch the testcase 

to account for this change.

llvm-svn: 68093
This commit is contained in:
Owen Anderson 2009-03-31 08:27:09 +00:00
parent c4b08e5eb0
commit 4486c1fac0
2 changed files with 60 additions and 127 deletions
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185
llvm/lib/CodeGen/PreAllocSplitting.cpp
View File

@ -232,68 +232,38 @@ PreAllocSplitting::findSpillPoint(MachineBasicBlock *MBB, MachineInstr *MI,
unsigned &SpillIndex) {
MachineBasicBlock::iterator Pt = MBB->begin();
// Go top down if RefsInMBB is empty.
if (RefsInMBB.empty() && !DefMI) {
MachineBasicBlock::iterator MII = MBB->begin();
MachineBasicBlock::iterator EndPt = MI;
MachineBasicBlock::iterator MII = MI;
MachineBasicBlock::iterator EndPt = DefMI
? MachineBasicBlock::iterator(DefMI) : MBB->begin();
if (MII == EndPt) return Pt;
while (MII != EndPt && !RefsInMBB.count(MII) &&
MII->getOpcode() != TRI->getCallFrameSetupOpcode())
--MII;
if (MII == EndPt || RefsInMBB.count(MII)) return Pt;
do {
++MII;
unsigned Index = LIs->getInstructionIndex(MII);
unsigned Gap = LIs->findGapBeforeInstr(Index);
// 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;
}
} while (MII != EndPt);
} else {
MachineBasicBlock::iterator MII = MI;
MachineBasicBlock::iterator EndPt = DefMI
? MachineBasicBlock::iterator(DefMI) : MBB->begin();
while (MII != EndPt && !RefsInMBB.count(MII)) {
unsigned Index = LIs->getInstructionIndex(MII);
while (MII != EndPt && !RefsInMBB.count(MII)) {
unsigned Index = LIs->getInstructionIndex(MII);
// We can't insert the spill between the barrier (a call), and its
// corresponding call frame setup.
if (prior(MII)->getOpcode() == TRI->getCallFrameSetupOpcode()) {
// We can't insert the spill between the barrier (a call), and its
// corresponding call frame setup.
if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {
while (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 (MII == EndPt) {
return Pt;
}
if (reachedBarrier) break;
else continue;
} else if (LIs->hasGapBeforeInstr(Index)) {
Pt = MII;
SpillIndex = LIs->findGapBeforeInstr(Index, true);
}
--MII;
continue;
} else if (LIs->hasGapBeforeInstr(Index)) {
Pt = MII;
SpillIndex = LIs->findGapBeforeInstr(Index, true);
}
if (RefsInMBB.count(MII))
return Pt;
--MII;
}
return Pt;
@ -311,81 +281,44 @@ PreAllocSplitting::findRestorePoint(MachineBasicBlock *MBB, MachineInstr *MI,
// FIXME: Allow spill to be inserted to the beginning of the mbb. Update mbb
// begin index accordingly.
MachineBasicBlock::iterator Pt = MBB->end();
unsigned EndIdx = LIs->getMBBEndIdx(MBB);
MachineBasicBlock::iterator EndPt = MBB->getFirstTerminator();
// Go bottom up if RefsInMBB is empty and the end of the mbb isn't beyond
// the last index in the live range.
if (RefsInMBB.empty() && LastIdx >= EndIdx) {
MachineBasicBlock::iterator MII = MBB->getFirstTerminator();
MachineBasicBlock::iterator EndPt = MI;
if (MII == EndPt) return Pt;
--MII;
do {
unsigned Index = LIs->getInstructionIndex(MII);
unsigned Gap = LIs->findGapBeforeInstr(Index);
// We start at the call, so walk forward until we find the call frame teardown
// since we can't insert restores before that. Bail if we encounter a use
// during this time.
MachineBasicBlock::iterator MII = MI;
if (MII == EndPt) return Pt;
while (MII != EndPt && !RefsInMBB.count(MII) &&
MII->getOpcode() != TRI->getCallFrameDestroyOpcode())
++MII;
if (MII == EndPt || RefsInMBB.count(MII)) return Pt;
++MII;
// FIXME: Limit the number of instructions to examine to reduce
// compile time?
while (MII != EndPt) {
unsigned Index = LIs->getInstructionIndex(MII);
if (Index > LastIdx)
break;
unsigned Gap = LIs->findGapBeforeInstr(Index);
// We can't insert a restore between the barrier (a call) and its
// corresponding call frame teardown.
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;
// FIXME: Limit the number of instructions to examine to reduce
// compile time?
while (MII != MBB->getFirstTerminator()) {
unsigned Index = LIs->getInstructionIndex(MII);
if (Index > LastIdx)
break;
unsigned Gap = LIs->findGapBeforeInstr(Index);
// We can't insert a restore between the barrier (a call) and its
// corresponding call frame teardown.
if (MII->getOpcode() == TRI->getCallFrameDestroyOpcode()) {
// We can't insert a restore between the barrier (a call) and its
// corresponding call frame teardown.
if (MII->getOpcode() == TRI->getCallFrameSetupOpcode()) {
do {
if (MII == EndPt || RefsInMBB.count(MII)) return Pt;
++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;
} while (MII->getOpcode() != TRI->getCallFrameDestroyOpcode());
} else if (Gap) {
Pt = MII;
RestoreIndex = Gap;
}
if (RefsInMBB.count(MII))
return Pt;
++MII;
}
return Pt;

2
llvm/test/CodeGen/X86/pre-split4.ll
View File

@ -1,5 +1,5 @@
; RUN: llvm-as < %s | llc -march=x86 -mattr=+sse2 -pre-alloc-split -stats |& \
; RUN: grep {pre-alloc-split} | grep {Number of intervals split} | grep 4
; RUN: grep {pre-alloc-split} | grep {Number of intervals split} | grep 2
define i32 @main(i32 %argc, i8** %argv) nounwind {
entry: