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[DAG] Cleanup unused node in SimplifySelectCC. 

Delete temporarily constructed node uses for analysis after it's use,
holding onto original input nodes. Ideally this would be rewritten
without making nodes, but this appears relatively complex.

Reviewers: spatel, RKSimon, craig.topper

Subscribers: jdoerfert, hiraditya, deadalnix, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D57921

llvm-svn: 356382
This commit is contained in:
Nirav Dave 2019-03-18 17:02:38 +00:00
parent c131e0e2ae
commit 55c921f4bf
2 changed files with 9 additions and 11 deletions
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11
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -18934,14 +18934,13 @@ SDValue DAGCombiner::SimplifySelectCC(const SDLoc &DL, SDValue N0, SDValue N1,
auto *N3C = dyn_cast<ConstantSDNode>(N3.getNode());
// Determine if the condition we're dealing with is constant.
SDValue SCC = SimplifySetCC(getSetCCResultType(CmpOpVT), N0, N1, CC, DL,
false);
if (SCC.getNode()) AddToWorklist(SCC.getNode());
if (auto *SCCC = dyn_cast_or_null<ConstantSDNode>(SCC.getNode())) {
if (SDValue SCC = DAG.FoldSetCC(VT, N0, N1, CC, DL)) {
AddToWorklist(SCC.getNode());
if (auto *SCCC = dyn_cast<ConstantSDNode>(SCC)) {
// fold select_cc true, x, y -> x
// fold select_cc false, x, y -> y
return !SCCC->isNullValue() ? N2 : N3;
return !(SCCC->isNullValue()) ? N2 : N3;
}
}
if (SDValue V =

5
llvm/test/CodeGen/X86/xor.ll
View File

@ -419,15 +419,14 @@ define i32 @PR17487(i1 %tobool) {
;
; X64-LIN-LABEL: PR17487:
; X64-LIN: # %bb.0:
; X64-LIN-NEXT: movd %edi, %xmm0
; X64-LIN-NEXT: pextrw $0, %xmm0, %eax
; X64-LIN-NEXT: movl %edi, %eax
; X64-LIN-NEXT: andl $1, %eax
; X64-LIN-NEXT: retq
;
; X64-WIN-LABEL: PR17487:
; X64-WIN: # %bb.0:
; X64-WIN-NEXT: andb $1, %cl
; X64-WIN-NEXT: movzbl %cl, %eax
; X64-WIN-NEXT: andl $1, %eax
; X64-WIN-NEXT: retq
%tmp = insertelement <2 x i1> undef, i1 %tobool, i32 1
%tmp1 = zext <2 x i1> %tmp to <2 x i64>