[llvm] r291092 - AVX-512: Optimized pattern for truncate with unsigned saturation.

Michael Kuperstein via llvm-commits llvm-commits at lists.llvm.org
Mon Jan 9 13:17:04 PST 2017


Hi Elena,I've reverted this in r291478, because it introduced a crash
during legalization.
PR31589 has the reproducer.

On Thu, Jan 5, 2017 at 12:21 AM, Elena Demikhovsky via llvm-commits <
llvm-commits at lists.llvm.org> wrote:

> Author: delena
> Date: Thu Jan  5 02:21:09 2017
> New Revision: 291092
>
> URL: http://llvm.org/viewvc/llvm-project?rev=291092&view=rev
> Log:
> AVX-512: Optimized pattern for truncate with unsigned saturation.
>
> DAG patterns optimization: truncate + unsigned saturation supported by
> VPMOVUS* instructions in AVX-512.
> Differential revision: https://reviews.llvm.org/D28216
>
> Modified:
>     llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
>     llvm/trunk/test/CodeGen/X86/avx512-trunc.ll
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/
> X86/X86ISelLowering.cpp?rev=291092&r1=291091&r2=291092&view=diff
> ============================================================
> ==================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Thu Jan  5 02:21:09 2017
> @@ -30921,6 +30921,59 @@ static SDValue foldVectorXorShiftIntoCmp
>    return DAG.getNode(X86ISD::PCMPGT, SDLoc(N), VT, Shift.getOperand(0),
> Ones);
>  }
>
> +/// Check if truncation with saturation form type \p SrcVT to \p DstVT
> +/// is valid for the given \p Subtarget.
> +static bool
> +isSATValidOnSubtarget(EVT SrcVT, EVT DstVT, const X86Subtarget
> &Subtarget) {
> +  if (!Subtarget.hasAVX512())
> +    return false;
> +  EVT SrcElVT = SrcVT.getScalarType();
> +  EVT DstElVT = DstVT.getScalarType();
> +  if (SrcElVT.getSizeInBits() < 16 || SrcElVT.getSizeInBits() > 64)
> +    return false;
> +  if (DstElVT.getSizeInBits() < 8 || DstElVT.getSizeInBits() > 32)
> +    return false;
> +  if (SrcVT.is512BitVector() || Subtarget.hasVLX())
> +    return SrcElVT.getSizeInBits() >= 32 || Subtarget.hasBWI();
> +  return false;
> +}
> +
> +/// Detect a pattern of truncation with saturation:
> +/// (truncate (umin (x, unsigned_max_of_dest_type)) to dest_type).
> +/// Return the source value to be truncated or SDValue() if the pattern
> was not
> +/// matched or the unsupported on the current target.
> +static SDValue
> +detectUSatPattern(SDValue In, EVT VT, const X86Subtarget &Subtarget) {
> +  if (In.getOpcode() != ISD::UMIN)
> +    return SDValue();
> +
> +  EVT InVT = In.getValueType();
> +  // FIXME: Scalar type may be supported if we move it to vector register.
> +  if (!InVT.isVector() || !InVT.isSimple())
> +    return SDValue();
> +
> +  if (!isSATValidOnSubtarget(InVT, VT, Subtarget))
> +    return SDValue();
> +
> +  //Saturation with truncation. We truncate from InVT to VT.
> +  assert(InVT.getScalarSizeInBits() > VT.getScalarSizeInBits() &&
> +    "Unexpected types for truncate operation");
> +
> +  SDValue SrcVal;
> +  APInt C;
> +  if (ISD::isConstantSplatVector(In.getOperand(0).getNode(), C))
> +    SrcVal = In.getOperand(1);
> +  else if (ISD::isConstantSplatVector(In.getOperand(1).getNode(), C))
> +    SrcVal = In.getOperand(0);
> +  else
> +    return SDValue();
> +
> +  // C should be equal to UINT32_MAX / UINT16_MAX / UINT8_MAX according
> +  // the element size of the destination type.
> +  return (C == ((uint64_t)1 << VT.getScalarSizeInBits()) - 1) ?
> +    SrcVal : SDValue();
> +}
> +
>  /// This function detects the AVG pattern between vectors of unsigned
> i8/i16,
>  /// which is c = (a + b + 1) / 2, and replace this operation with the
> efficient
>  /// X86ISD::AVG instruction.
> @@ -31487,6 +31540,12 @@ static SDValue combineStore(SDNode *N, S
>                            St->getPointerInfo(), St->getAlignment(),
>                            St->getMemOperand()->getFlags());
>
> +    if (SDValue Val =
> +        detectUSatPattern(St->getValue(), St->getMemoryVT(), Subtarget))
> +      return EmitTruncSStore(false /* Unsigned saturation */,
> St->getChain(),
> +                             dl, Val, St->getBasePtr(),
> +                             St->getMemoryVT(), St->getMemOperand(), DAG);
> +
>      const TargetLowering &TLI = DAG.getTargetLoweringInfo();
>      unsigned NumElems = VT.getVectorNumElements();
>      assert(StVT != VT && "Cannot truncate to the same type");
> @@ -32104,6 +32163,10 @@ static SDValue combineTruncate(SDNode *N
>    if (SDValue Avg = detectAVGPattern(Src, VT, DAG, Subtarget, DL))
>      return Avg;
>
> +  // Try the truncation with unsigned saturation.
> +  if (SDValue Val = detectUSatPattern(Src, VT, Subtarget))
> +    return DAG.getNode(X86ISD::VTRUNCUS, DL, VT, Val);
> +
>    // The bitcast source is a direct mmx result.
>    // Detect bitcasts between i32 to x86mmx
>    if (Src.getOpcode() == ISD::BITCAST && VT == MVT::i32) {
>
> Modified: llvm/trunk/test/CodeGen/X86/avx512-trunc.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/
> CodeGen/X86/avx512-trunc.ll?rev=291092&r1=291091&r2=291092&view=diff
> ============================================================
> ==================
> --- llvm/trunk/test/CodeGen/X86/avx512-trunc.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/avx512-trunc.ll Thu Jan  5 02:21:09 2017
> @@ -500,3 +500,110 @@ define void @trunc_wb_128_mem(<8 x i16>
>      store <8 x i8> %x, <8 x i8>* %res
>      ret void
>  }
> +
> +
> +define void @usat_trunc_wb_256_mem(<16 x i16> %i, <16 x i8>* %res) {
> +; KNL-LABEL: usat_trunc_wb_256_mem:
> +; KNL:       ## BB#0:
> +; KNL-NEXT:    vpminuw {{.*}}(%rip), %ymm0, %ymm0
> +; KNL-NEXT:    vpmovsxwd %ymm0, %zmm0
> +; KNL-NEXT:    vpmovdb %zmm0, %xmm0
> +; KNL-NEXT:    vmovdqu %xmm0, (%rdi)
> +; KNL-NEXT:    retq
> +;
> +; SKX-LABEL: usat_trunc_wb_256_mem:
> +; SKX:       ## BB#0:
> +; SKX-NEXT:    vpmovuswb %ymm0, (%rdi)
> +; SKX-NEXT:    retq
> +  %x3 = icmp ult <16 x i16> %i, <i16 255, i16 255, i16 255, i16 255, i16
> 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16
> 255, i16 255, i16 255, i16 255>
> +  %x5 = select <16 x i1> %x3, <16 x i16> %i, <16 x i16> <i16 255, i16
> 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16
> 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255>
> +  %x6 = trunc <16 x i16> %x5 to <16 x i8>
> +  store <16 x i8> %x6, <16 x i8>* %res, align 1
> +  ret void
> +}
> +
> +define <16 x i8> @usat_trunc_wb_256(<16 x i16> %i) {
> +; KNL-LABEL: usat_trunc_wb_256:
> +; KNL:       ## BB#0:
> +; KNL-NEXT:    vpminuw {{.*}}(%rip), %ymm0, %ymm0
> +; KNL-NEXT:    vpmovsxwd %ymm0, %zmm0
> +; KNL-NEXT:    vpmovdb %zmm0, %xmm0
> +; KNL-NEXT:    retq
> +;
> +; SKX-LABEL: usat_trunc_wb_256:
> +; SKX:       ## BB#0:
> +; SKX-NEXT:    vpmovuswb %ymm0, %xmm0
> +; SKX-NEXT:    retq
> +  %x3 = icmp ult <16 x i16> %i, <i16 255, i16 255, i16 255, i16 255, i16
> 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16
> 255, i16 255, i16 255, i16 255>
> +  %x5 = select <16 x i1> %x3, <16 x i16> %i, <16 x i16> <i16 255, i16
> 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16
> 255, i16 255, i16 255, i16 255, i16 255, i16 255, i16 255>
> +  %x6 = trunc <16 x i16> %x5 to <16 x i8>
> +  ret <16 x i8> %x6
> +}
> +
> +define void @usat_trunc_wb_128_mem(<8 x i16> %i, <8 x i8>* %res) {
> +; KNL-LABEL: usat_trunc_wb_128_mem:
> +; KNL:       ## BB#0:
> +; KNL-NEXT:    vpminuw {{.*}}(%rip), %xmm0, %xmm0
> +; KNL-NEXT:    vpshufb {{.*#+}} xmm0 = xmm0[0,2,4,6,8,10,12,14,u,u,u,
> u,u,u,u,u]
> +; KNL-NEXT:    vmovq %xmm0, (%rdi)
> +; KNL-NEXT:    retq
> +;
> +; SKX-LABEL: usat_trunc_wb_128_mem:
> +; SKX:       ## BB#0:
> +; SKX-NEXT:    vpmovuswb %xmm0, (%rdi)
> +; SKX-NEXT:    retq
> +  %x3 = icmp ult <8 x i16> %i, <i16 255, i16 255, i16 255, i16 255, i16
> 255, i16 255, i16 255, i16 255>
> +  %x5 = select <8 x i1> %x3, <8 x i16> %i, <8 x i16> <i16 255, i16 255,
> i16 255, i16 255, i16 255, i16 255, i16 255, i16 255>
> +  %x6 = trunc <8 x i16> %x5 to <8 x i8>
> +  store <8 x i8> %x6, <8 x i8>* %res, align 1
> +  ret void
> +}
> +
> +define void @usat_trunc_db_512_mem(<16 x i32> %i, <16 x i8>* %res) {
> +; ALL-LABEL: usat_trunc_db_512_mem:
> +; ALL:       ## BB#0:
> +; ALL-NEXT:    vpmovusdb %zmm0, (%rdi)
> +; ALL-NEXT:    retq
> +  %x3 = icmp ult <16 x i32> %i, <i32 255, i32 255, i32 255, i32 255, i32
> 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32
> 255, i32 255, i32 255, i32 255>
> +  %x5 = select <16 x i1> %x3, <16 x i32> %i, <16 x i32> <i32 255, i32
> 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32
> 255, i32 255, i32 255, i32 255, i32 255, i32 255, i32 255>
> +  %x6 = trunc <16 x i32> %x5 to <16 x i8>
> +  store <16 x i8> %x6, <16 x i8>* %res, align 1
> +  ret void
> +}
> +
> +define void @usat_trunc_qb_512_mem(<8 x i64> %i, <8 x i8>* %res) {
> +; ALL-LABEL: usat_trunc_qb_512_mem:
> +; ALL:       ## BB#0:
> +; ALL-NEXT:    vpmovusqb %zmm0, (%rdi)
> +; ALL-NEXT:    retq
> +  %x3 = icmp ult <8 x i64> %i, <i64 255, i64 255, i64 255, i64 255, i64
> 255, i64 255, i64 255, i64 255>
> +  %x5 = select <8 x i1> %x3, <8 x i64> %i, <8 x i64> <i64 255, i64 255,
> i64 255, i64 255, i64 255, i64 255, i64 255, i64 255>
> +  %x6 = trunc <8 x i64> %x5 to <8 x i8>
> +  store <8 x i8> %x6, <8 x i8>* %res, align 1
> +  ret void
> +}
> +
> +define void @usat_trunc_qd_512_mem(<8 x i64> %i, <8 x i32>* %res) {
> +; ALL-LABEL: usat_trunc_qd_512_mem:
> +; ALL:       ## BB#0:
> +; ALL-NEXT:    vpmovusqd %zmm0, (%rdi)
> +; ALL-NEXT:    retq
> +  %x3 = icmp ult <8 x i64> %i, <i64 4294967295, i64 4294967295, i64
> 4294967295, i64 4294967295, i64 4294967295, i64 4294967295, i64 4294967295,
> i64 4294967295>
> +  %x5 = select <8 x i1> %x3, <8 x i64> %i, <8 x i64> <i64 4294967295, i64
> 4294967295, i64 4294967295, i64 4294967295, i64 4294967295, i64 4294967295,
> i64 4294967295, i64 4294967295>
> +  %x6 = trunc <8 x i64> %x5 to <8 x i32>
> +  store <8 x i32> %x6, <8 x i32>* %res, align 1
> +  ret void
> +}
> +
> +define void @usat_trunc_qw_512_mem(<8 x i64> %i, <8 x i16>* %res) {
> +; ALL-LABEL: usat_trunc_qw_512_mem:
> +; ALL:       ## BB#0:
> +; ALL-NEXT:    vpmovusqw %zmm0, (%rdi)
> +; ALL-NEXT:    retq
> +  %x3 = icmp ult <8 x i64> %i, <i64 65535, i64 65535, i64 65535, i64
> 65535, i64 65535, i64 65535, i64 65535, i64 65535>
> +  %x5 = select <8 x i1> %x3, <8 x i64> %i, <8 x i64> <i64 65535, i64
> 65535, i64 65535, i64 65535, i64 65535, i64 65535, i64 65535, i64 65535>
> +  %x6 = trunc <8 x i64> %x5 to <8 x i16>
> +  store <8 x i16> %x6, <8 x i16>* %res, align 1
> +  ret void
> +}
> +
>
>
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