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Drop the REDEF_BY_EC VNInfo flag.

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A live range that has an early clobber tied redef now looks like a
normal tied redef, except the early clobber def uses the early clobber
slot.

This is enough to handle any strange interference problems.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@149769 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Jakob Stoklund Olesen
2012-02-04 05:51:25 +00:00
parent 7e899cbb91
commit 0aad7d274d
4 changed files with 2 additions and 51 deletions
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33
lib/CodeGen/RegisterCoalescer.cpp
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@@ -438,27 +438,6 @@ bool RegisterCoalescer::AdjustCopiesBackFrom(const CoalescerPair &CP,
// The live range might not exist after fun with physreg coalescing.
if (ALR == IntA.end()) return false;
VNInfo *AValNo = ALR->valno;
// If it's re-defined by an early clobber somewhere in the live range, then
// it's not safe to eliminate the copy. FIXME: This is a temporary workaround.
// See PR3149:
// 172 %ECX<def> = MOV32rr %reg1039<kill>
// 180 INLINEASM <es:subl $5,$1
// sbbl $3,$0>, 10, %EAX<def>, 14, %ECX<earlyclobber,def>, 9,
// %EAX<kill>,
// 36, <fi#0>, 1, %reg0, 0, 9, %ECX<kill>, 36, <fi#1>, 1, %reg0, 0
// 188 %EAX<def> = MOV32rr %EAX<kill>
// 196 %ECX<def> = MOV32rr %ECX<kill>
// 204 %ECX<def> = MOV32rr %ECX<kill>
// 212 %EAX<def> = MOV32rr %EAX<kill>
// 220 %EAX<def> = MOV32rr %EAX
// 228 %reg1039<def> = MOV32rr %ECX<kill>
// The early clobber operand ties ECX input to the ECX def.
//
// The live interval of ECX is represented as this:
// %reg20,inf = [46,47:1)[174,230:0) 0@174-(230) 1@46-(47)
// The coalescer has no idea there was a def in the middle of [174,230].
if (AValNo->hasRedefByEC())
return false;
// If AValNo is defined as a copy from IntB, we can potentially process this.
// Get the instruction that defines this value number.
@@ -1510,10 +1489,6 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) {
if (!MI->isCopyLike()) // Src not defined by a copy?
continue;
// Never join with a register that has EarlyClobber redefs.
if (VNI->hasRedefByEC())
return false;
// Figure out the value # from the RHS.
LiveRange *lr = RHS.getLiveRangeContaining(VNI->def.getPrevSlot());
// The copy could be to an aliased physreg.
@@ -1540,10 +1515,6 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) {
if (!MI->isCopyLike()) // Src not defined by a copy?
continue;
// Never join with a register that has EarlyClobber redefs.
if (VNI->hasRedefByEC())
return false;
// Figure out the value # from the LHS.
LiveRange *lr = LHS.getLiveRangeContaining(VNI->def.getPrevSlot());
// The copy could be to an aliased physreg.
@@ -1624,10 +1595,6 @@ bool RegisterCoalescer::JoinIntervals(CoalescerPair &CP) {
if (LHSValNoAssignments[I->valno->id] !=
RHSValNoAssignments[J->valno->id])
return false;
// If it's re-defined by an early clobber somewhere in the live range,
// then conservatively abort coalescing.
if (NewVNInfo[LHSValNoAssignments[I->valno->id]]->hasRedefByEC())
return false;
}
if (I->end < J->end)