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Erase joined copies immediately. 

The late dead code elimination is no longer necessary.

The test changes are cause by a register hint that can be either %rdi or
%rax. The choice depends on the use list order, which this patch changes.

llvm-svn: 157131
This commit is contained in:
Jakob Stoklund Olesen 2012-05-19 20:54:07 +00:00
parent 1b707c8817
commit 25ced18407
2 changed files with 16 additions and 14 deletions
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18
llvm/lib/CodeGen/RegisterCoalescer.cpp
View File

@ -766,7 +766,9 @@ bool RegisterCoalescer::removeCopyByCommutingDef(const CoalescerPair &CP,
DEBUG(dbgs() << "\t\tnoop: " << DefIdx << '\t' << *UseMI);
assert(DVNI->def == DefIdx);
BValNo = IntB.MergeValueNumberInto(BValNo, DVNI);
markAsJoined(UseMI);
ErasedInstrs.insert(UseMI);
LIS->RemoveMachineInstrFromMaps(UseMI);
UseMI->eraseFromParent();
}
// Extend BValNo by merging in IntA live ranges of AValNo. Val# definition
@ -1127,7 +1129,8 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
if (!CP.isPartial()) {
if (adjustCopiesBackFrom(CP, CopyMI) ||
removeCopyByCommutingDef(CP, CopyMI)) {
markAsJoined(CopyMI);
LIS->RemoveMachineInstrFromMaps(CopyMI);
CopyMI->eraseFromParent();
DEBUG(dbgs() << "\tTrivial!\n");
return true;
}
@ -1152,7 +1155,8 @@ bool RegisterCoalescer::joinCopy(MachineInstr *CopyMI, bool &Again) {
InflateRegs.push_back(CP.getDstReg());
// Remember to delete the copy instruction.
markAsJoined(CopyMI);
LIS->RemoveMachineInstrFromMaps(CopyMI);
CopyMI->eraseFromParent();
// Rewrite all SrcReg operands to DstReg.
// Also update DstReg operands to include DstIdx if it is set.
@ -1518,13 +1522,11 @@ bool RegisterCoalescer::joinIntervals(CoalescerPair &CP) {
// was actually a copy from A. Now that we decided to coalesce A and B,
// transform the code into
// A = X
// X = X
// and mark the X as coalesced to keep the illusion.
unsigned Src = MI->getOperand(1).getReg();
SourceRegisters.push_back(Src);
MI->getOperand(0).substVirtReg(Src, 0, *TRI);
markAsJoined(MI);
ErasedInstrs.insert(MI);
LIS->RemoveMachineInstrFromMaps(MI);
MI->eraseFromParent();
}
// If B = X was the last use of X in a liverange, we have to shrink it now

12
llvm/test/CodeGen/X86/segmented-stacks-dynamic.ll
View File

@ -51,14 +51,14 @@ false:
; X64-NEXT: callq __morestack
; X64-NEXT: ret
; X64: movq %rsp, %rdi
; X64-NEXT: subq %rax, %rdi
; X64-NEXT: cmpq %rdi, %fs:112
; X64: movq %rsp, %[[RDI:rdi|rax]]
; X64-NEXT: subq %{{.*}}, %[[RDI]]
; X64-NEXT: cmpq %[[RDI]], %fs:112
; X64: movq %rdi, %rsp
; X64: movq %[[RDI]], %rsp
; X64: movq %rax, %rdi
; X64: movq %{{.*}}, %rdi
; X64-NEXT: callq __morestack_allocate_stack_space
; X64-NEXT: movq %rax, %rdi
; X64: movq %rax, %rdi
}