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- Fix a subtle bug in RemoveCopyByCommutingDef. ALR is the live range where the source is defined; BLR is the live range which is defined by the copy.

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If ALR and BLR overlaps and end of BLR extends beyond end of ALR, e.g.                                                                                                 
 A = or A, B                                                                                                                                                            
 ...                                                                                                                                                                    
 B = A                                                                                                                                                                  
 ...                                                                                                                                                                    
 C = A<kill>                                                                                                                                                            
 ...                                                                                                                                                                    
   = B                                                                                                                                                                  
                                                                                                                                                                        
then do not add kills of A to the newly created B interval.
- Also fix some kill info update bug.

llvm-svn: 48141
This commit is contained in:
Evan Cheng 2008-03-10 08:11:32 +00:00
parent 554d2c443b
commit 02b66c3a32
3 changed files with 77 additions and 7 deletions
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59
lib/CodeGen/SimpleRegisterCoalescing.cpp
View File

@ -310,11 +310,26 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
unsigned OpIdx = NewMI->findRegisterUseOperandIdx(IntA.reg, false);
NewMI->getOperand(OpIdx).setIsKill();
// Update uses of IntA of the specific Val# with IntB.
bool BHasPHIKill = BValNo->hasPHIKill;
SmallVector<VNInfo*, 4> BDeadValNos;
SmallVector<unsigned, 4> BKills;
std::map<unsigned, unsigned> BExtend;
// If ALR and BLR overlaps and end of BLR extends beyond end of ALR, e.g.
// A = or A, B
// ...
// B = A
// ...
// C = A<kill>
// ...
// = B
//
// then do not add kills of A to the newly created B interval.
bool Extended = BLR->end > ALR->end && ALR->end != ALR->start;
if (Extended)
BExtend[ALR->end] = BLR->end;
// Update uses of IntA of the specific Val# with IntB.
for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(IntA.reg),
UE = mri_->use_end(); UI != UE;) {
MachineOperand &UseMO = UI.getOperand();
@ -329,8 +344,12 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
UseMO.setReg(NewReg);
if (UseMI == CopyMI)
continue;
if (UseMO.isKill())
BKills.push_back(li_->getUseIndex(UseIdx)+1);
if (UseMO.isKill()) {
if (Extended)
UseMO.setIsKill(false);
else
BKills.push_back(li_->getUseIndex(UseIdx)+1);
}
unsigned SrcReg, DstReg;
if (!tii_->isMoveInstr(*UseMI, SrcReg, DstReg))
continue;
@ -347,9 +366,8 @@ bool SimpleRegisterCoalescing::RemoveCopyByCommutingDef(LiveInterval &IntA,
JoinedCopies.insert(UseMI);
// If this is a kill but it's going to be removed, the last use
// of the same val# is the new kill.
if (UseMO.isKill()) {
if (UseMO.isKill())
BKills.pop_back();
}
}
}
@ -451,6 +469,29 @@ SimpleRegisterCoalescing::UpdateRegDefsUses(unsigned SrcReg, unsigned DstReg,
}
}
/// RemoveUnnecessaryKills - Remove kill markers that are no longer accurate
/// due to live range lengthening as the result of coalescing.
void SimpleRegisterCoalescing::RemoveUnnecessaryKills(unsigned Reg,
LiveInterval &LI) {
for (MachineRegisterInfo::use_iterator UI = mri_->use_begin(Reg),
UE = mri_->use_end(); UI != UE; ++UI) {
MachineOperand &UseMO = UI.getOperand();
if (UseMO.isKill()) {
MachineInstr *UseMI = UseMO.getParent();
unsigned SReg, DReg;
if (!tii_->isMoveInstr(*UseMI, SReg, DReg))
continue;
unsigned UseIdx = li_->getUseIndex(li_->getInstructionIndex(UseMI));
if (JoinedCopies.count(UseMI))
continue;
LiveInterval::const_iterator UI = LI.FindLiveRangeContaining(UseIdx);
assert(UI != LI.end());
if (!LI.isKill(UI->valno, UseIdx+1))
UseMO.setIsKill(false);
}
}
}
/// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
/// extended by a dead copy. Mark the last use (if any) of the val# as kill
/// as ends the live range there. If there isn't another use, then this
@ -803,6 +844,12 @@ bool SimpleRegisterCoalescing::JoinCopy(CopyRec &TheCopy, bool &Again) {
// Remember to delete the copy instruction.
JoinedCopies.insert(CopyMI);
// Some live range has been lengthened due to colaescing, eliminate the
// unnecessary kills.
RemoveUnnecessaryKills(SrcReg, *ResDstInt);
if (TargetRegisterInfo::isVirtualRegister(DstReg))
RemoveUnnecessaryKills(DstReg, *ResDstInt);
// SrcReg is guarateed to be the register whose live interval that is
// being merged.
li_->removeInterval(SrcReg);
@ -1481,8 +1528,6 @@ SimpleRegisterCoalescing::lastRegisterUse(unsigned Start, unsigned End,
}
/// RemoveUnnecessaryKills - Remove kill markers that are no longer accurate
/// due to live range lengthening as the result of coalescing.
void SimpleRegisterCoalescing::printRegName(unsigned reg) const {
if (TargetRegisterInfo::isPhysicalRegister(reg))
cerr << tri_->getName(reg);

4
lib/CodeGen/SimpleRegisterCoalescing.h
View File

@ -201,6 +201,10 @@ namespace llvm {
/// subregister.
void UpdateRegDefsUses(unsigned SrcReg, unsigned DstReg, unsigned SubIdx);
/// RemoveUnnecessaryKills - Remove kill markers that are no longer accurate
/// due to live range lengthening as the result of coalescing.
void RemoveUnnecessaryKills(unsigned Reg, LiveInterval &LI);
/// ShortenDeadCopyLiveRange - Shorten a live range as it's artificially
/// extended by a dead copy. Mark the last use (if any) of the val# as kill
/// as ends the live range there. If there isn't another use, then this

21
test/CodeGen/X86/coalescer-commute5.ll Normal file
View File

@ -0,0 +1,21 @@
; RUN: llvm-as < %s | llc -mtriple=i686-apple-darwin -mattr=+sse2 | not grep movaps
define i32 @t() {
entry:
br i1 true, label %bb1664, label %bb1656
bb1656: ; preds = %entry
ret i32 0
bb1664: ; preds = %entry
%tmp4297 = bitcast <16 x i8> zeroinitializer to <2 x i64> ; <<2 x i64>> [#uses=2]
%tmp4351 = call <16 x i8> @llvm.x86.sse2.pcmpeq.b( <16 x i8> zeroinitializer, <16 x i8> zeroinitializer ) nounwind readnone ; <<16 x i8>> [#uses=0]
br i1 false, label %bb5310, label %bb4743
bb4743: ; preds = %bb1664
%tmp4360.not28 = or <2 x i64> zeroinitializer, %tmp4297 ; <<2 x i64>> [#uses=1]
br label %bb5310
bb5310: ; preds = %bb4743, %bb1664
%tmp4360.not28.pn = phi <2 x i64> [ %tmp4360.not28, %bb4743 ], [ %tmp4297, %bb1664 ] ; <<2 x i64>> [#uses=1]
%tmp4415.not.pn = or <2 x i64> zeroinitializer, %tmp4360.not28.pn ; <<2 x i64>> [#uses=0]
ret i32 0
}
declare <16 x i8> @llvm.x86.sse2.pcmpeq.b(<16 x i8>, <16 x i8>) nounwind readnone