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Fix bug: Jello/2003-08-23-RegisterAllocatePhysReg.ll 

llvm-svn: 8095
This commit is contained in:
Chris Lattner 2003-08-23 23:49:42 +00:00
parent 3be2088ae7
commit e6235443a5
1 changed files with 21 additions and 13 deletions
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34
llvm/lib/CodeGen/RegAllocLocal.cpp
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@ -400,19 +400,27 @@ unsigned RA::getReg(MachineBasicBlock &MBB, MachineBasicBlock::iterator &I,
"Couldn't find a register of the appropriate class!");
unsigned R = PhysRegsUseOrder[i];
// If the current register is compatible, use it.
if (RegInfo->getRegClass(R) == RC) {
PhysReg = R;
break;
} else {
// If one of the registers aliased to the current register is
// compatible, use it.
if (const unsigned *AliasSet = RegInfo->getAliasSet(R))
for (unsigned a = 0; AliasSet[a]; ++a)
if (RegInfo->getRegClass(AliasSet[a]) == RC) {
PhysReg = AliasSet[a]; // Take an aliased register
break;
}
// We can only use this register if it holds a virtual register (ie, it
// can be spilled). Do not use it if it is an explicitly allocated
// physical register!
assert(PhysRegsUsed.count(R) &&
"PhysReg in PhysRegsUseOrder, but is not allocated?");
if (PhysRegsUsed[R]) {
// If the current register is compatible, use it.
if (RegInfo->getRegClass(R) == RC) {
PhysReg = R;
break;
} else {
// If one of the registers aliased to the current register is
// compatible, use it.
if (const unsigned *AliasSet = RegInfo->getAliasSet(R))
for (unsigned a = 0; AliasSet[a]; ++a)
if (RegInfo->getRegClass(AliasSet[a]) == RC) {
PhysReg = AliasSet[a]; // Take an aliased register
break;
}
}
}
}