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Handle implicit_defs in the register coalescer. I am still trying to produce

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a reduced testcase, but this fixes pr13209.

llvm-svn: 159479
This commit is contained in:
Rafael Espindola 2012-06-30 01:45:55 +00:00
parent 54c59fa2db
commit 065c63c4ca
1 changed files with 40 additions and 27 deletions
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67
lib/CodeGen/RegisterCoalescer.cpp
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@ -1172,14 +1172,11 @@ static bool RegistersDefinedFromSameValue(LiveIntervals &li,
MachineInstr *MI = li.getInstructionFromIndex(VNI->def);
if (!MI || !MI->isFullCopy() || CP.isPartial() || CP.isPhys())
if (!MI || CP.isPartial() || CP.isPhys())
return false;
unsigned Dst = MI->getOperand(0).getReg();
unsigned Src = MI->getOperand(1).getReg();
if (!TargetRegisterInfo::isVirtualRegister(Src) ||
!TargetRegisterInfo::isVirtualRegister(Dst))
if (!TargetRegisterInfo::isVirtualRegister(Dst))
return false;
unsigned A = CP.getDstReg();
@ -1189,34 +1186,47 @@ static bool RegistersDefinedFromSameValue(LiveIntervals &li,
std::swap(A, B);
assert(Dst == A);
const MachineInstr *OtherMI = li.getInstructionFromIndex(OtherVNI->def);
MachineInstr *OtherMI = li.getInstructionFromIndex(OtherVNI->def);
if (!OtherMI || !OtherMI->isFullCopy())
if (!OtherMI)
return false;
unsigned OtherDst = OtherMI->getOperand(0).getReg();
unsigned OtherSrc = OtherMI->getOperand(1).getReg();
if (!TargetRegisterInfo::isVirtualRegister(OtherSrc) ||
!TargetRegisterInfo::isVirtualRegister(OtherDst))
if (!TargetRegisterInfo::isVirtualRegister(OtherDst))
return false;
assert(OtherDst == B);
if (Src != OtherSrc)
return false;
if (MI->isImplicitDef()) {
DupCopies.push_back(MI);
return true;
} else {
if (!MI->isFullCopy())
return false;
unsigned Src = MI->getOperand(1).getReg();
if (!TargetRegisterInfo::isVirtualRegister(Src))
return false;
if (!OtherMI->isFullCopy())
return false;
unsigned OtherSrc = OtherMI->getOperand(1).getReg();
if (!TargetRegisterInfo::isVirtualRegister(OtherSrc))
return false;
// If the copies use two different value numbers of X, we cannot merge
// A and B.
LiveInterval &SrcInt = li.getInterval(Src);
// getVNInfoBefore returns NULL for undef copies. In this case, the
// optimization is still safe.
if (SrcInt.getVNInfoBefore(OtherVNI->def) != SrcInt.getVNInfoBefore(VNI->def))
return false;
if (Src != OtherSrc)
return false;
DupCopies.push_back(MI);
// If the copies use two different value numbers of X, we cannot merge
// A and B.
LiveInterval &SrcInt = li.getInterval(Src);
// getVNInfoBefore returns NULL for undef copies. In this case, the
// optimization is still safe.
if (SrcInt.getVNInfoBefore(OtherVNI->def) !=
SrcInt.getVNInfoBefore(VNI->def))
return false;
return true;
DupCopies.push_back(MI);
return true;
}
}
/// joinIntervals - Attempt to join these two intervals. On failure, this
@ -1254,7 +1264,7 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
continue;
MachineInstr *MI = LIS->getInstructionFromIndex(VNI->def);
assert(MI && "Missing def");
if (!MI->isCopyLike()) // Src not defined by a copy?
if (!MI->isCopyLike() && !MI->isImplicitDef()) // Src not defined by a copy?
continue;
// Figure out the value # from the RHS.
@ -1283,7 +1293,7 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
continue;
MachineInstr *MI = LIS->getInstructionFromIndex(VNI->def);
assert(MI && "Missing def");
if (!MI->isCopyLike()) // Src not defined by a copy?
if (!MI->isCopyLike() && !MI->isImplicitDef()) // Src not defined by a copy?
continue;
// Figure out the value # from the LHS.
@ -1429,14 +1439,17 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
if (!ErasedInstrs.insert(MI))
continue;
// We have pretended that the assignment to B in
// If MI is a copy, then we have pretended that the assignment to B in
// A = X
// B = X
// was actually a copy from A. Now that we decided to coalesce A and B,
// transform the code into
// A = X
unsigned Src = MI->getOperand(1).getReg();
SourceRegisters.push_back(Src);
// In the case of the implicit_def, we just have to remove it.
if (!MI->isImplicitDef()) {
unsigned Src = MI->getOperand(1).getReg();
SourceRegisters.push_back(Src);
}
LIS->RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
}