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[DAGCombiner] Support (shl (zext (srl x, C)), C) -> (zext (shl (srl x, C), C)) non-uniform folds. 

Use matchBinaryPredicate instead of isConstOrConstSplat to let us handle non-uniform shift cases. 

llvm-svn: 363929
This commit is contained in:
Simon Pilgrim 2019-06-20 14:42:27 +00:00
parent 249fde8583
commit 1d8093249f
2 changed files with 32 additions and 44 deletions
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36
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -7259,25 +7259,27 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {
// fold (shl (zext (srl x, C)), C) -> (zext (shl (srl x, C), C))
// Only fold this if the inner zext has no other uses to avoid increasing
// the total number of instructions.
// TODO - support non-uniform vector shift amounts.
if (N1C && N0.getOpcode() == ISD::ZERO_EXTEND && N0.hasOneUse() &&
if (N0.getOpcode() == ISD::ZERO_EXTEND && N0.hasOneUse() &&
N0.getOperand(0).getOpcode() == ISD::SRL) {
SDValue N0Op0 = N0.getOperand(0);
if (ConstantSDNode *N0Op0C1 = isConstOrConstSplat(N0Op0.getOperand(1))) {
if (N0Op0C1->getAPIntValue().ult(VT.getScalarSizeInBits())) {
uint64_t c1 = N0Op0C1->getZExtValue();
uint64_t c2 = N1C->getZExtValue();
if (c1 == c2) {
SDValue NewOp0 = N0.getOperand(0);
EVT CountVT = NewOp0.getOperand(1).getValueType();
SDLoc DL(N);
SDValue NewSHL = DAG.getNode(ISD::SHL, DL, NewOp0.getValueType(),
NewOp0,
DAG.getConstant(c2, DL, CountVT));
AddToWorklist(NewSHL.getNode());
return DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N0), VT, NewSHL);
}
}
SDValue InnerShiftAmt = N0Op0.getOperand(1);
EVT InnerShiftAmtVT = N0Op0.getOperand(1).getValueType();
auto MatchEqual = [VT](ConstantSDNode *LHS, ConstantSDNode *RHS) {
APInt c1 = LHS->getAPIntValue();
APInt c2 = RHS->getAPIntValue();
zeroExtendToMatch(c1, c2);
return c1.ult(VT.getScalarSizeInBits()) && (c1 == c2);
};
if (ISD::matchBinaryPredicate(InnerShiftAmt, N1, MatchEqual,
/*AllowUndefs*/ false,
/*AllowTypeMismatch*/ true)) {
SDLoc DL(N);
EVT InnerShiftAmtVT = N0Op0.getOperand(1).getValueType();
SDValue NewSHL = DAG.getZExtOrTrunc(N1, DL, InnerShiftAmtVT);
NewSHL = DAG.getNode(ISD::SHL, DL, N0Op0.getValueType(), N0Op0, NewSHL);
AddToWorklist(NewSHL.getNode());
return DAG.getNode(ISD::ZERO_EXTEND, SDLoc(N0), VT, NewSHL);
}
}

40
llvm/test/CodeGen/X86/combine-shl.ll
View File

@ -363,44 +363,30 @@ define <8 x i32> @combine_vec_shl_zext_lshr0(<8 x i16> %x) {
define <8 x i32> @combine_vec_shl_zext_lshr1(<8 x i16> %x) {
; SSE2-LABEL: combine_vec_shl_zext_lshr1:
; SSE2: # %bb.0:
; SSE2-NEXT: pmulhuw {{.*}}(%rip), %xmm0
; SSE2-NEXT: pxor %xmm1, %xmm1
; SSE2-NEXT: movdqa %xmm0, %xmm2
; SSE2-NEXT: punpckhwd {{.*#+}} xmm2 = xmm2[4],xmm1[4],xmm2[5],xmm1[5],xmm2[6],xmm1[6],xmm2[7],xmm1[7]
; SSE2-NEXT: punpcklwd {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1],xmm0[2],xmm1[2],xmm0[3],xmm1[3]
; SSE2-NEXT: movdqa {{.*#+}} xmm1 = [2,4,8,16]
; SSE2-NEXT: pshufd {{.*#+}} xmm3 = xmm0[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm1, %xmm0
; SSE2-NEXT: pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
; SSE2-NEXT: pshufd {{.*#+}} xmm1 = xmm1[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm3, %xmm1
; SSE2-NEXT: pshufd {{.*#+}} xmm1 = xmm1[0,2,2,3]
; SSE2-NEXT: punpckldq {{.*#+}} xmm0 = xmm0[0],xmm1[0],xmm0[1],xmm1[1]
; SSE2-NEXT: movdqa {{.*#+}} xmm3 = [32,64,128,256]
; SSE2-NEXT: pshufd {{.*#+}} xmm4 = xmm2[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm3, %xmm2
; SSE2-NEXT: pshufd {{.*#+}} xmm1 = xmm2[0,2,2,3]
; SSE2-NEXT: pshufd {{.*#+}} xmm2 = xmm3[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm4, %xmm2
; SSE2-NEXT: pshufd {{.*#+}} xmm2 = xmm2[0,2,2,3]
; SSE2-NEXT: punpckldq {{.*#+}} xmm1 = xmm1[0],xmm2[0],xmm1[1],xmm2[1]
; SSE2-NEXT: movdqa %xmm0, %xmm1
; SSE2-NEXT: pmulhuw {{.*}}(%rip), %xmm1
; SSE2-NEXT: pxor %xmm2, %xmm2
; SSE2-NEXT: pmullw {{.*}}(%rip), %xmm1
; SSE2-NEXT: movdqa %xmm1, %xmm0
; SSE2-NEXT: punpcklwd {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1],xmm0[2],xmm2[2],xmm0[3],xmm2[3]
; SSE2-NEXT: punpckhwd {{.*#+}} xmm1 = xmm1[4],xmm2[4],xmm1[5],xmm2[5],xmm1[6],xmm2[6],xmm1[7],xmm2[7]
; SSE2-NEXT: retq
;
; SSE41-LABEL: combine_vec_shl_zext_lshr1:
; SSE41: # %bb.0:
; SSE41-NEXT: pmulhuw {{.*}}(%rip), %xmm0
; SSE41-NEXT: pshufd {{.*#+}} xmm1 = xmm0[2,3,0,1]
; SSE41-NEXT: pmovzxwd {{.*#+}} xmm1 = xmm1[0],zero,xmm1[1],zero,xmm1[2],zero,xmm1[3],zero
; SSE41-NEXT: pmovzxwd {{.*#+}} xmm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
; SSE41-NEXT: pmulld {{.*}}(%rip), %xmm0
; SSE41-NEXT: pmulld {{.*}}(%rip), %xmm1
; SSE41-NEXT: pmullw {{.*}}(%rip), %xmm0
; SSE41-NEXT: pmovzxwd {{.*#+}} xmm2 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
; SSE41-NEXT: pshufd {{.*#+}} xmm0 = xmm0[2,3,0,1]
; SSE41-NEXT: pmovzxwd {{.*#+}} xmm1 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero
; SSE41-NEXT: movdqa %xmm2, %xmm0
; SSE41-NEXT: retq
;
; AVX-LABEL: combine_vec_shl_zext_lshr1:
; AVX: # %bb.0:
; AVX-NEXT: vpmulhuw {{.*}}(%rip), %xmm0, %xmm0
; AVX-NEXT: vpmullw {{.*}}(%rip), %xmm0, %xmm0
; AVX-NEXT: vpmovzxwd {{.*#+}} ymm0 = xmm0[0],zero,xmm0[1],zero,xmm0[2],zero,xmm0[3],zero,xmm0[4],zero,xmm0[5],zero,xmm0[6],zero,xmm0[7],zero
; AVX-NEXT: vpsllvd {{.*}}(%rip), %ymm0, %ymm0
; AVX-NEXT: retq
%1 = lshr <8 x i16> %x, <i16 1, i16 2, i16 3, i16 4, i16 5, i16 6, i16 7, i16 8>
%2 = zext <8 x i16> %1 to <8 x i32>