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[X86] Improve lowering of v16i8->v16i1 truncate under prefer-vector-width=256.

This commit is contained in:
Craig Topper 2020-04-25 15:00:19 -07:00
parent 42bf0756d4
commit c1cb733db6
2 changed files with 17 additions and 14 deletions
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21
llvm/lib/Target/X86/X86ISelLowering.cpp
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@ -20382,17 +20382,22 @@ static SDValue LowerTruncateVecI1(SDValue Op, SelectionDAG &DAG,
// trying to avoid 512-bit vectors. If we are avoiding 512-bit vectors
// we need to split into two 8 element vectors which we can extend to v8i32,
// truncate and concat the results. There's an additional complication if
// the original type is v16i8. In that case we can't split the v16i8 so
// first we pre-extend it to v16i16 which we can split to v8i16, then extend
// to v8i32, truncate that to v8i1 and concat the two halves.
// the original type is v16i8. In that case we can't split the v16i8
// directly, so we need to shuffle high elements to low and use
// sign_extend_vector_inreg.
if (NumElts == 16 && !Subtarget.canExtendTo512DQ()) {
SDValue Lo, Hi;
if (InVT == MVT::v16i8) {
// First we need to sign extend up to 256-bits so we can split that.
InVT = MVT::v16i16;
In = DAG.getNode(ISD::SIGN_EXTEND, DL, InVT, In);
Lo = DAG.getNode(ISD::SIGN_EXTEND_VECTOR_INREG, DL, MVT::v8i32, In);
Hi = DAG.getVectorShuffle(
InVT, DL, In, In,
{8, 9, 10, 11, 12, 13, 14, 15, -1, -1, -1, -1, -1, -1, -1, -1});
Hi = DAG.getNode(ISD::SIGN_EXTEND_VECTOR_INREG, DL, MVT::v8i32, Hi);
} else {
assert(InVT == MVT::v16i16 && "Unexpected VT!");
Lo = extract128BitVector(In, 0, DAG, DL);
Hi = extract128BitVector(In, 8, DAG, DL);
}
SDValue Lo = extract128BitVector(In, 0, DAG, DL);
SDValue Hi = extract128BitVector(In, 8, DAG, DL);
// We're split now, just emit two truncates and a concat. The two
// truncates will trigger legalization to come back to this function.
Lo = DAG.getNode(ISD::TRUNCATE, DL, MVT::v8i1, Lo);

10
llvm/test/CodeGen/X86/prefer-avx256-mask-shuffle.ll
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@ -133,14 +133,12 @@ define <32 x i1> @shuf32i1_3_6_22_12_3_7_7_0_3_6_1_13_3_21_7_0_3_6_22_12_3_7_7_0
; AVX256VL-NEXT: vpxor %xmm1, %xmm1, %xmm1
; AVX256VL-NEXT: vpcmpeqb %ymm1, %ymm0, %ymm0
; AVX256VL-NEXT: vextracti128 $1, %ymm0, %xmm1
; AVX256VL-NEXT: vpmovsxbw %xmm1, %xmm1
; AVX256VL-NEXT: vpmovsxwd %xmm1, %ymm1
; AVX256VL-NEXT: vpmovsxbd %xmm1, %ymm1
; AVX256VL-NEXT: vptestmd %ymm1, %ymm1, %k1
; AVX256VL-NEXT: vpmovsxbw %xmm0, %ymm0
; AVX256VL-NEXT: vextracti128 $1, %ymm0, %xmm1
; AVX256VL-NEXT: vpmovsxwd %xmm1, %ymm1
; AVX256VL-NEXT: vpshufd {{.*#+}} xmm1 = xmm0[2,3,0,1]
; AVX256VL-NEXT: vpmovsxbd %xmm1, %ymm1
; AVX256VL-NEXT: vptestmd %ymm1, %ymm1, %k2
; AVX256VL-NEXT: vpmovsxwd %xmm0, %ymm0
; AVX256VL-NEXT: vpmovsxbd %xmm0, %ymm0
; AVX256VL-NEXT: vptestmd %ymm0, %ymm0, %k3
; AVX256VL-NEXT: vpcmpeqd %ymm0, %ymm0, %ymm0
; AVX256VL-NEXT: vmovdqa32 %ymm0, %ymm1 {%k3} {z}