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Teach live intervals to not crash on dead livein regs

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git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@23206 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner 2005-09-02 00:20:32 +00:00
parent fab08875b7
commit 5ab6f5fe66
3 changed files with 15 additions and 8 deletions
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3
include/llvm/CodeGen/LiveIntervalAnalysis.h
View File

@ -164,7 +164,8 @@ namespace llvm {
void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
LiveInterval& interval,
unsigned SrcReg, unsigned DestReg);
unsigned SrcReg, unsigned DestReg,
bool isLiveIn = false);
/// Return true if the two specified registers belong to different
/// register classes. The registers may be either phys or virt regs.

17
lib/CodeGen/LiveIntervalAnalysis.cpp
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@ -131,10 +131,10 @@ bool LiveIntervals::runOnMachineFunction(MachineFunction &fn) {
for (MachineFunction::livein_iterator I = fn.livein_begin(),
E = fn.livein_end(); I != E; ++I) {
handlePhysicalRegisterDef(Entry, Entry->begin(),
getOrCreateInterval(I->first), 0, 0);
getOrCreateInterval(I->first), 0, 0, true);
for (const unsigned* AS = mri_->getAliasSet(I->first); *AS; ++AS)
handlePhysicalRegisterDef(Entry, Entry->begin(),
getOrCreateInterval(*AS), 0, 0);
getOrCreateInterval(*AS), 0, 0, true);
}
}
@ -478,7 +478,8 @@ void LiveIntervals::handleVirtualRegisterDef(MachineBasicBlock* mbb,
void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock *MBB,
MachineBasicBlock::iterator mi,
LiveInterval& interval,
unsigned SrcReg, unsigned DestReg)
unsigned SrcReg, unsigned DestReg,
bool isLiveIn)
{
// A physical register cannot be live across basic block, so its
// lifetime must end somewhere in its defining basic block.
@ -501,9 +502,7 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock *MBB,
// If it is not dead on definition, it must be killed by a
// subsequent instruction. Hence its interval is:
// [defSlot(def), useSlot(kill)+1)
while (true) {
++mi;
assert(mi != MBB->end() && "physreg was not killed in defining block!");
while (++mi != MBB->end()) {
baseIndex += InstrSlots::NUM;
if (lv_->KillsRegister(mi, interval.reg)) {
DEBUG(std::cerr << " killed");
@ -511,6 +510,12 @@ void LiveIntervals::handlePhysicalRegisterDef(MachineBasicBlock *MBB,
goto exit;
}
}
// The only case we should have a dead physreg here without a killing or
// instruction where we know it's dead is if it is live-in to the function
// and never used.
assert(isLiveIn && "physreg was not killed in defining block!");
end = getDefIndex(start) + 1; // It's dead.
exit:
assert(start < end && "did not find end of interval?");

3
lib/CodeGen/LiveIntervalAnalysis.h
View File

@ -164,7 +164,8 @@ namespace llvm {
void handlePhysicalRegisterDef(MachineBasicBlock* mbb,
MachineBasicBlock::iterator mi,
LiveInterval& interval,
unsigned SrcReg, unsigned DestReg);
unsigned SrcReg, unsigned DestReg,
bool isLiveIn = false);
/// Return true if the two specified registers belong to different
/// register classes. The registers may be either phys or virt regs.