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[DAGCombiner] Support (shl (ext (shl x, c1)), c2) -> (shl (ext x), (add c1, c2)) non-uniform folds. 

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

llvm-svn: 363793
This commit is contained in:
Simon Pilgrim 2019-06-19 12:41:37 +00:00
parent 8c49366c9b
commit 9eed5d2f78
2 changed files with 39 additions and 42 deletions
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31
llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
View File

@ -7232,23 +7232,22 @@ SDValue DAGCombiner::visitSHL(SDNode *N) {
/*AllowTypeMismatch*/ true))
return DAG.getConstant(0, SDLoc(N), VT);
ConstantSDNode *N0Op0C1 = isConstOrConstSplat(InnerShiftAmt);
if (N1C && N0Op0C1) {
APInt c1 = N0Op0C1->getAPIntValue();
APInt c2 = N1C->getAPIntValue();
auto MatchInRange = [OpSizeInBits, InnerBitwidth](ConstantSDNode *LHS,
ConstantSDNode *RHS) {
APInt c1 = LHS->getAPIntValue();
APInt c2 = RHS->getAPIntValue();
zeroExtendToMatch(c1, c2, 1 /* Overflow Bit */);
if (c2.uge(OpSizeInBits - InnerBitwidth)) {
SDLoc DL(N0);
APInt Sum = c1 + c2;
if (Sum.uge(OpSizeInBits))
return DAG.getConstant(0, DL, VT);
return DAG.getNode(
ISD::SHL, DL, VT,
DAG.getNode(N0.getOpcode(), DL, VT, N0Op0->getOperand(0)),
DAG.getConstant(Sum.getZExtValue(), DL, ShiftVT));
}
return c2.uge(OpSizeInBits - InnerBitwidth) &&
(c1 + c2).ult(OpSizeInBits);
};
if (ISD::matchBinaryPredicate(InnerShiftAmt, N1, MatchInRange,
/*AllowUndefs*/ false,
/*AllowTypeMismatch*/ true)) {
SDLoc DL(N);
SDValue Ext = DAG.getNode(N0.getOpcode(), DL, VT, N0Op0.getOperand(0));
SDValue Sum = DAG.getZExtOrTrunc(InnerShiftAmt, DL, ShiftVT);
Sum = DAG.getNode(ISD::ADD, DL, ShiftVT, Sum, N1);
return DAG.getNode(ISD::SHL, DL, VT, Ext, Sum);
}
}

50
llvm/test/CodeGen/X86/combine-shl.ll
View File

@ -281,46 +281,44 @@ define <8 x i32> @combine_vec_shl_ext_shl1(<8 x i16> %x) {
ret <8 x i32> %3
}
; TODO - this should fold to shl(ext(%x),c).
define <8 x i32> @combine_vec_shl_ext_shl2(<8 x i16> %x) {
; SSE2-LABEL: combine_vec_shl_ext_shl2:
; SSE2: # %bb.0:
; SSE2-NEXT: pmullw {{.*}}(%rip), %xmm0
; SSE2-NEXT: punpckhwd {{.*#+}} xmm1 = xmm1[4],xmm0[4],xmm1[5],xmm0[5],xmm1[6],xmm0[6],xmm1[7],xmm0[7]
; SSE2-NEXT: punpcklwd {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1],xmm1[2],xmm0[2],xmm1[3],xmm0[3]
; SSE2-NEXT: psrad $16, %xmm1
; SSE2-NEXT: punpcklwd {{.*#+}} xmm0 = xmm0[0,0,1,1,2,2,3,3]
; SSE2-NEXT: psrad $16, %xmm0
; SSE2-NEXT: movdqa {{.*#+}} xmm2 = [65536,131072,262144,524288]
; SSE2-NEXT: pshufd {{.*#+}} xmm3 = xmm0[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm2, %xmm0
; SSE2-NEXT: pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
; SSE2-NEXT: pshufd {{.*#+}} xmm2 = xmm2[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm3, %xmm2
; SSE2-NEXT: pshufd {{.*#+}} xmm2 = xmm2[0,2,2,3]
; SSE2-NEXT: punpckldq {{.*#+}} xmm0 = xmm0[0],xmm2[0],xmm0[1],xmm2[1]
; SSE2-NEXT: movdqa {{.*#+}} xmm2 = [1048576,2097152,4194304,8388608]
; SSE2-NEXT: pshufd {{.*#+}} xmm3 = xmm1[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm2, %xmm1
; SSE2-NEXT: movdqa {{.*#+}} xmm3 = [131072,524288,2097152,8388608]
; SSE2-NEXT: pshufd {{.*#+}} xmm4 = xmm1[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm3, %xmm1
; SSE2-NEXT: pshufd {{.*#+}} xmm2 = xmm1[0,2,2,3]
; SSE2-NEXT: pshufd {{.*#+}} xmm1 = xmm3[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm4, %xmm1
; SSE2-NEXT: pshufd {{.*#+}} xmm1 = xmm1[0,2,2,3]
; SSE2-NEXT: pshufd {{.*#+}} xmm2 = xmm2[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm3, %xmm2
; SSE2-NEXT: pshufd {{.*#+}} xmm2 = xmm2[0,2,2,3]
; SSE2-NEXT: punpckldq {{.*#+}} xmm1 = xmm1[0],xmm2[0],xmm1[1],xmm2[1]
; SSE2-NEXT: punpckldq {{.*#+}} xmm2 = xmm2[0],xmm1[0],xmm2[1],xmm1[1]
; SSE2-NEXT: punpckhwd {{.*#+}} xmm0 = xmm0[4,4,5,5,6,6,7,7]
; SSE2-NEXT: psrad $16, %xmm0
; SSE2-NEXT: movdqa {{.*#+}} xmm3 = [33554432,134217728,536870912,2147483648]
; SSE2-NEXT: pshufd {{.*#+}} xmm4 = xmm0[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm3, %xmm0
; SSE2-NEXT: pshufd {{.*#+}} xmm1 = xmm0[0,2,2,3]
; SSE2-NEXT: pshufd {{.*#+}} xmm0 = xmm3[1,1,3,3]
; SSE2-NEXT: pmuludq %xmm4, %xmm0
; SSE2-NEXT: pshufd {{.*#+}} xmm0 = xmm0[0,2,2,3]
; SSE2-NEXT: punpckldq {{.*#+}} xmm1 = xmm1[0],xmm0[0],xmm1[1],xmm0[1]
; SSE2-NEXT: movdqa %xmm2, %xmm0
; SSE2-NEXT: retq
;
; SSE41-LABEL: combine_vec_shl_ext_shl2:
; SSE41: # %bb.0:
; SSE41-NEXT: pmullw {{.*}}(%rip), %xmm0
; SSE41-NEXT: pshufd {{.*#+}} xmm1 = xmm0[2,3,0,1]
; SSE41-NEXT: pmovsxwd %xmm1, %xmm1
; SSE41-NEXT: pmovsxwd %xmm0, %xmm0
; SSE41-NEXT: pmulld {{.*}}(%rip), %xmm0
; SSE41-NEXT: pmovsxwd %xmm0, %xmm2
; SSE41-NEXT: pmulld {{.*}}(%rip), %xmm2
; SSE41-NEXT: pshufd {{.*#+}} xmm0 = xmm0[2,3,0,1]
; SSE41-NEXT: pmovsxwd %xmm0, %xmm1
; SSE41-NEXT: pmulld {{.*}}(%rip), %xmm1
; SSE41-NEXT: movdqa %xmm2, %xmm0
; SSE41-NEXT: retq
;
; AVX-LABEL: combine_vec_shl_ext_shl2:
; AVX: # %bb.0:
; AVX-NEXT: vpmullw {{.*}}(%rip), %xmm0, %xmm0
; AVX-NEXT: vpmovsxwd %xmm0, %ymm0
; AVX-NEXT: vpsllvd {{.*}}(%rip), %ymm0, %ymm0
; AVX-NEXT: retq