[llvm] r343373 - [X86][SSE] Fixed issue with v2i64 variable shifts on 32-bit targets

Simon Pilgrim via llvm-commits llvm-commits at lists.llvm.org
Sat Sep 29 07:01:56 PDT 2018


Hans,

I'd like to recommend this for merging into 7.0.1 - its a regression 
from 6.0.0.

Cheers, Simon.

On 29/09/2018 14:25, Simon Pilgrim via llvm-commits wrote:
> Author: rksimon
> Date: Sat Sep 29 06:25:22 2018
> New Revision: 343373
>
> URL: http://llvm.org/viewvc/llvm-project?rev=343373&view=rev
> Log:
> [X86][SSE] Fixed issue with v2i64 variable shifts on 32-bit targets
>
> The shift amount might have peeked through a extract_subvector, altering the number of vector elements in the 'Amt' variable - so we were incorrectly calculating the ratio when peeking through bitcasts, resulting in incorrectly detecting splats.
>
> Modified:
>      llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
>      llvm/trunk/test/CodeGen/X86/known-signbits-vector.ll
>      llvm/trunk/test/CodeGen/X86/packss.ll
>
> Modified: llvm/trunk/lib/Target/X86/X86ISelLowering.cpp
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Target/X86/X86ISelLowering.cpp?rev=343373&r1=343372&r2=343373&view=diff
> ==============================================================================
> --- llvm/trunk/lib/Target/X86/X86ISelLowering.cpp (original)
> +++ llvm/trunk/lib/Target/X86/X86ISelLowering.cpp Sat Sep 29 06:25:22 2018
> @@ -23711,15 +23711,14 @@ static SDValue LowerScalarVariableShift(
>     }
>   
>     // Check cases (mainly 32-bit) where i64 is expanded into high and low parts.
> -  if (VT == MVT::v2i64  && Amt.getOpcode() == ISD::BITCAST &&
> +  if (VT == MVT::v2i64 && Amt.getOpcode() == ISD::BITCAST &&
>         Amt.getOperand(0).getOpcode() == ISD::BUILD_VECTOR) {
>       Amt = Amt.getOperand(0);
> -    unsigned Ratio = Amt.getSimpleValueType().getVectorNumElements() /
> -                     VT.getVectorNumElements();
> +    unsigned Ratio = 64 / Amt.getScalarValueSizeInBits();
>       std::vector<SDValue> Vals(Ratio);
>       for (unsigned i = 0; i != Ratio; ++i)
>         Vals[i] = Amt.getOperand(i);
> -    for (unsigned i = Ratio; i != Amt.getNumOperands(); i += Ratio) {
> +    for (unsigned i = Ratio, e = Amt.getNumOperands(); i != e; i += Ratio) {
>         for (unsigned j = 0; j != Ratio; ++j)
>           if (Vals[j] != Amt.getOperand(i + j))
>             return SDValue();
>
> Modified: llvm/trunk/test/CodeGen/X86/known-signbits-vector.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/known-signbits-vector.ll?rev=343373&r1=343372&r2=343373&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/known-signbits-vector.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/known-signbits-vector.ll Sat Sep 29 06:25:22 2018
> @@ -381,19 +381,26 @@ define <4 x float> @signbits_ashr_sext_s
>   ; X32-NEXT:    movl %esp, %ebp
>   ; X32-NEXT:    andl $-16, %esp
>   ; X32-NEXT:    subl $16, %esp
> +; X32-NEXT:    vmovdqa {{.*#+}} xmm3 = [33,0,63,0]
> +; X32-NEXT:    vmovdqa {{.*#+}} xmm4 = [0,2147483648,0,2147483648]
> +; X32-NEXT:    vpsrlq %xmm3, %xmm4, %xmm5
> +; X32-NEXT:    vpshufd {{.*#+}} xmm6 = xmm3[2,3,0,1]
> +; X32-NEXT:    vpsrlq %xmm6, %xmm4, %xmm4
> +; X32-NEXT:    vpblendw {{.*#+}} xmm4 = xmm5[0,1,2,3],xmm4[4,5,6,7]
> +; X32-NEXT:    vextractf128 $1, %ymm2, %xmm5
> +; X32-NEXT:    vpsrlq %xmm6, %xmm5, %xmm7
> +; X32-NEXT:    vpsrlq %xmm3, %xmm5, %xmm5
> +; X32-NEXT:    vpblendw {{.*#+}} xmm5 = xmm5[0,1,2,3],xmm7[4,5,6,7]
> +; X32-NEXT:    vpsrlq %xmm6, %xmm2, %xmm6
> +; X32-NEXT:    vpsrlq %xmm3, %xmm2, %xmm2
> +; X32-NEXT:    vpblendw {{.*#+}} xmm2 = xmm2[0,1,2,3],xmm6[4,5,6,7]
>   ; X32-NEXT:    vpmovsxdq 16(%ebp), %xmm3
> +; X32-NEXT:    vpxor %xmm4, %xmm5, %xmm5
> +; X32-NEXT:    vpsubq %xmm4, %xmm5, %xmm5
> +; X32-NEXT:    vpxor %xmm4, %xmm2, %xmm2
> +; X32-NEXT:    vpsubq %xmm4, %xmm2, %xmm2
>   ; X32-NEXT:    vpmovsxdq 8(%ebp), %xmm4
> -; X32-NEXT:    vmovdqa {{.*#+}} xmm5 = [33,0,63,0]
> -; X32-NEXT:    vmovdqa {{.*#+}} xmm6 = [0,2147483648,0,2147483648]
> -; X32-NEXT:    vpsrlq %xmm5, %xmm6, %xmm6
> -; X32-NEXT:    vextractf128 $1, %ymm2, %xmm7
> -; X32-NEXT:    vpsrlq %xmm5, %xmm7, %xmm7
> -; X32-NEXT:    vpxor %xmm6, %xmm7, %xmm7
> -; X32-NEXT:    vpsubq %xmm6, %xmm7, %xmm7
> -; X32-NEXT:    vpsrlq %xmm5, %xmm2, %xmm2
> -; X32-NEXT:    vpxor %xmm6, %xmm2, %xmm2
> -; X32-NEXT:    vpsubq %xmm6, %xmm2, %xmm2
> -; X32-NEXT:    vinsertf128 $1, %xmm7, %ymm2, %ymm2
> +; X32-NEXT:    vinsertf128 $1, %xmm5, %ymm2, %ymm2
>   ; X32-NEXT:    vinsertf128 $1, %xmm3, %ymm4, %ymm3
>   ; X32-NEXT:    vextractf128 $1, %ymm1, %xmm4
>   ; X32-NEXT:    vextractf128 $1, %ymm0, %xmm5
>
> Modified: llvm/trunk/test/CodeGen/X86/packss.ll
> URL: http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/packss.ll?rev=343373&r1=343372&r2=343373&view=diff
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/packss.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/packss.ll Sat Sep 29 06:25:22 2018
> @@ -183,16 +183,27 @@ define <8 x i16> @trunc_ashr_v4i64_deman
>   ; X86-AVX1-NEXT:    movl $63, %eax
>   ; X86-AVX1-NEXT:    vmovd %eax, %xmm1
>   ; X86-AVX1-NEXT:    vpsllq %xmm1, %xmm0, %xmm2
> +; X86-AVX1-NEXT:    vpshufd {{.*#+}} xmm3 = xmm1[2,3,0,1]
> +; X86-AVX1-NEXT:    vpsllq %xmm3, %xmm0, %xmm4
> +; X86-AVX1-NEXT:    vpblendw {{.*#+}} xmm2 = xmm2[0,1,2,3],xmm4[4,5,6,7]
>   ; X86-AVX1-NEXT:    vextractf128 $1, %ymm0, %xmm0
> -; X86-AVX1-NEXT:    vpsllq %xmm1, %xmm0, %xmm0
> -; X86-AVX1-NEXT:    vmovdqa {{.*#+}} xmm3 = [0,2147483648,0,2147483648]
> -; X86-AVX1-NEXT:    vpsrlq %xmm1, %xmm3, %xmm3
> +; X86-AVX1-NEXT:    vpsllq %xmm1, %xmm0, %xmm4
> +; X86-AVX1-NEXT:    vpsllq %xmm3, %xmm0, %xmm0
> +; X86-AVX1-NEXT:    vpblendw {{.*#+}} xmm0 = xmm4[0,1,2,3],xmm0[4,5,6,7]
> +; X86-AVX1-NEXT:    vpsrlq %xmm3, %xmm0, %xmm4
>   ; X86-AVX1-NEXT:    vpsrlq %xmm1, %xmm0, %xmm0
> -; X86-AVX1-NEXT:    vpxor %xmm3, %xmm0, %xmm0
> -; X86-AVX1-NEXT:    vpsubq %xmm3, %xmm0, %xmm0
> +; X86-AVX1-NEXT:    vpblendw {{.*#+}} xmm0 = xmm0[0,1,2,3],xmm4[4,5,6,7]
> +; X86-AVX1-NEXT:    vmovdqa {{.*#+}} xmm4 = [0,2147483648,0,2147483648]
> +; X86-AVX1-NEXT:    vpsrlq %xmm1, %xmm4, %xmm5
> +; X86-AVX1-NEXT:    vpsrlq %xmm3, %xmm4, %xmm4
> +; X86-AVX1-NEXT:    vpblendw {{.*#+}} xmm4 = xmm5[0,1,2,3],xmm4[4,5,6,7]
> +; X86-AVX1-NEXT:    vpxor %xmm4, %xmm0, %xmm0
> +; X86-AVX1-NEXT:    vpsubq %xmm4, %xmm0, %xmm0
> +; X86-AVX1-NEXT:    vpsrlq %xmm3, %xmm2, %xmm3
>   ; X86-AVX1-NEXT:    vpsrlq %xmm1, %xmm2, %xmm1
> -; X86-AVX1-NEXT:    vpxor %xmm3, %xmm1, %xmm1
> -; X86-AVX1-NEXT:    vpsubq %xmm3, %xmm1, %xmm1
> +; X86-AVX1-NEXT:    vpblendw {{.*#+}} xmm1 = xmm1[0,1,2,3],xmm3[4,5,6,7]
> +; X86-AVX1-NEXT:    vpxor %xmm4, %xmm1, %xmm1
> +; X86-AVX1-NEXT:    vpsubq %xmm4, %xmm1, %xmm1
>   ; X86-AVX1-NEXT:    vinsertf128 $1, %xmm0, %ymm1, %ymm0
>   ; X86-AVX1-NEXT:    vpermilps {{.*#+}} ymm0 = ymm0[0,0,0,0,4,4,4,4]
>   ; X86-AVX1-NEXT:    vextractf128 $1, %ymm0, %xmm1
>
>
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