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[DAGCombiner] (add X, (adde Y, 0, Carry)) -> (adde X, Y, Carry) 

Summary: This is extracted from D29443 .

Reviewers: mkuper, spatel, RKSimon, zvi, bkramer

Subscribers: llvm-commits

Differential Revision: https://reviews.llvm.org/D29564

llvm-svn: 294186
This commit is contained in:
Amaury Sechet 2017-02-06 14:28:39 +00:00
parent bdf3c5af6a
commit 1d466f598e
2 changed files with 12 additions and 7 deletions
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6
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -1834,6 +1834,12 @@ SDValue DAGCombiner::visitADDLike(SDValue N0, SDValue N1, SDNode *LocReference)
}
}
// (add X, (adde Y, 0, Carry)) -> (adde X, Y, Carry)
if (N1.getOpcode() == ISD::ADDE && N1->hasOneUse() &&
isNullConstant(N1.getOperand(1)))
return DAG.getNode(ISD::ADDE, DL, DAG.getVTList(VT, MVT::Glue),
N0, N1->getOperand(0), N1->getOperand(2));
return SDValue();
}

13
llvm/test/CodeGen/X86/adde-carry.ll
View File

@ -93,17 +93,16 @@ define %scalar @pr31719(%scalar* nocapture readonly %this, %scalar %arg.b) {
; CHECK-NEXT: sbbq %r10, %r10
; CHECK-NEXT: andl $1, %r10d
; CHECK-NEXT: addq 8(%rsi), %rcx
; CHECK-NEXT: sbbq %r11, %r11
; CHECK-NEXT: andl $1, %r11d
; CHECK-NEXT: addq %r10, %rcx
; CHECK-NEXT: adcq $0, %r11
; CHECK-NEXT: addq 16(%rsi), %r8
; CHECK-NEXT: sbbq %rax, %rax
; CHECK-NEXT: andl $1, %eax
; CHECK-NEXT: addq %r11, %r8
; CHECK-NEXT: addq %r10, %rcx
; CHECK-NEXT: adcq $0, %rax
; CHECK-NEXT: addq 16(%rsi), %r8
; CHECK-NEXT: sbbq %r10, %r10
; CHECK-NEXT: andl $1, %r10d
; CHECK-NEXT: addq 24(%rsi), %r9
; CHECK-NEXT: addq %rax, %r9
; CHECK-NEXT: addq %rax, %r8
; CHECK-NEXT: adcq %r10, %r9
; CHECK-NEXT: movq %rdx, (%rdi)
; CHECK-NEXT: movq %rcx, 8(%rdi)
; CHECK-NEXT: movq %r8, 16(%rdi)