[llvm] r209643 - Convert some X86 blendv* intrinsics into IR.
Daniel Jasper
djasper at google.com
Tue May 27 03:08:10 PDT 2014
On Tue, May 27, 2014 at 5:42 AM, Filipe Cabecinhas <me at filcab.net> wrote:
> Author: filcab
> Date: Mon May 26 22:42:20 2014
> New Revision: 209643
>
> URL: http://llvm.org/viewvc/llvm-project?rev=209643&view=rev
> Log:
> Convert some X86 blendv* intrinsics into IR.
>
> Summary:
> Implemented an InstCombine transformation that takes a blendv* intrinsic
> call and translates it into an IR select, if the mask is constant.
>
> This will eventually get lowered into blends with immediates if possible,
> or pblendvb (with an option to further optimize if we can transform the
> pblendvb into a blend+immediate instruction, depending on the selector).
> It will also enable optimizations by the IR passes, which give up on
> sight of the intrinsic.
>
> Both the transformation and the lowering of its result to asm got shiny
> new tests.
>
> The transformation is a bit convoluted because of blendvp[sd]'s
> definition:
>
> Its mask is a floating point value! This forces us to convert it and get
> the highest bit. I suppose this happened because the mask has type
> __m128 in Intel's intrinsic and v4sf (for blendps) in gcc's builtin.
>
> I will send an email to llvm-dev to discuss if we want to change this or
> not.
>
> Reviewers: grosbach, delena, nadav
>
> Differential Revision: http://reviews.llvm.org/D3859
>
> Added:
> llvm/trunk/test/CodeGen/X86/avx2-blend.ll
> llvm/trunk/test/Transforms/InstCombine/blend_x86.ll
> Modified:
> llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
> llvm/trunk/test/CodeGen/X86/avx-blend.ll
> llvm/trunk/test/CodeGen/X86/sse41-blend.ll
>
> Modified: llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp?rev=209643&r1=209642&r2=209643&view=diff
>
> ==============================================================================
> --- llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp (original)
> +++ llvm/trunk/lib/Transforms/InstCombine/InstCombineCalls.cpp Mon May 26
> 22:42:20 2014
> @@ -718,6 +718,41 @@ Instruction *InstCombiner::visitCallInst
> break;
> }
>
> + case Intrinsic::x86_sse41_pblendvb:
> + case Intrinsic::x86_sse41_blendvps:
> + case Intrinsic::x86_sse41_blendvpd:
> + case Intrinsic::x86_avx_blendv_ps_256:
> + case Intrinsic::x86_avx_blendv_pd_256:
> + case Intrinsic::x86_avx2_pblendvb: {
> + // Convert blendv* to vector selects if the mask is constant.
> + // This optimization is convoluted because the intrinsic is defined as
> + // getting a vector of floats or doubles for the ps and pd versions.
> + // FIXME: That should be changed.
> + Value *Mask = II->getArgOperand(2);
> + if (auto C = dyn_cast<ConstantDataVector>(Mask)) {
> + auto Tyi1 = Builder->getInt1Ty();
> + auto SelectorType = cast<VectorType>(Mask->getType());
> + auto EltTy = SelectorType->getElementType();
> + unsigned Size = SelectorType->getNumElements();
> + unsigned BitWidth = EltTy->isFloatTy() ? 32 : (EltTy->isDoubleTy()
> ? 64 : EltTy->getIntegerBitWidth());
> + assert(BitWidth == 64 || BitWidth == 32 || BitWidth == 8 && "Wrong
> arguments for variable blend intrinsic");
>
This is assert is bad in that it triggers Clang's operator precedence
warning and works correctly more or less by accident (consider the
precedence of || and && - with the string implicitly evaluating to true).
Fixed in r209648.
Also, please adhere to LLVM coding standards (most importantly the 80
column limit).
> + SmallVector<Constant*, 32> Selectors;
> + for (unsigned I = 0; I < Size; ++I) {
> + // The intrinsics only read the top bit
> + uint64_t Selector;
> + if (BitWidth == 8)
> + Selector = C->getElementAsInteger(I);
> + else
> + Selector =
> C->getElementAsAPFloat(I).bitcastToAPInt().getZExtValue();
> + Selectors.push_back(ConstantInt::get(Tyi1, Selector >> (BitWidth
> - 1)));
> + }
> + auto NewSelector = ConstantVector::get(Selectors);
> + return SelectInst::Create(NewSelector, II->getArgOperand(0),
> II->getArgOperand(1), "blendv");
> + } else {
> + break;
> + }
> + }
> +
> case Intrinsic::x86_avx_vpermilvar_ps:
> case Intrinsic::x86_avx_vpermilvar_ps_256:
> case Intrinsic::x86_avx_vpermilvar_pd:
>
> Modified: llvm/trunk/test/CodeGen/X86/avx-blend.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/avx-blend.ll?rev=209643&r1=209642&r2=209643&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/avx-blend.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/avx-blend.ll Mon May 26 22:42:20 2014
> @@ -135,3 +135,26 @@ define <2 x double> @testb(<2 x double>
> %min = select <2 x i1> %min_is_x, <2 x double> %x, <2 x double> %y
> ret <2 x double> %min
> }
> +
> +; If we can figure out a blend has a constant mask, we should emit the
> +; blend instruction with an immediate mask
> +define <4 x double> @constant_blendvpd_avx(<4 x double> %xy, <4 x double>
> %ab) {
> +; CHECK-LABEL: constant_blendvpd_avx:
> +; CHECK-NOT: mov
> +; CHECK: vblendpd
> +; CHECK: ret
> + %1 = select <4 x i1> <i1 false, i1 false, i1 true, i1 false>, <4 x
> double> %xy, <4 x double> %ab
> + ret <4 x double> %1
> +}
> +
> +define <8 x float> @constant_blendvps_avx(<8 x float> %xyzw, <8 x float>
> %abcd) {
> +; CHECK-LABEL: constant_blendvps_avx:
> +; CHECK-NOT: mov
> +; CHECK: vblendps
> +; CHECK: ret
> + %1 = select <8 x i1> <i1 false, i1 false, i1 false, i1 true, i1 false,
> i1 false, i1 false, i1 true>, <8 x float> %xyzw, <8 x float> %abcd
> + ret <8 x float> %1
> +}
> +
> +declare <8 x float> @llvm.x86.avx.blendv.ps.256(<8 x float>, <8 x float>,
> <8 x float>)
> +declare <4 x double> @llvm.x86.avx.blendv.pd.256(<4 x double>, <4 x
> double>, <4 x double>)
>
> Added: llvm/trunk/test/CodeGen/X86/avx2-blend.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/avx2-blend.ll?rev=209643&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/avx2-blend.ll (added)
> +++ llvm/trunk/test/CodeGen/X86/avx2-blend.ll Mon May 26 22:42:20 2014
> @@ -0,0 +1,11 @@
> +; RUN: llc < %s -mtriple=x86_64-apple-darwin -mcpu=core-avx2 | FileCheck
> %s
> +
> +define <32 x i8> @constant_pblendvb_avx2(<32 x i8> %xyzw, <32 x i8>
> %abcd) {
> +; CHECK-LABEL: constant_pblendvb_avx2:
> +; CHECK: vmovdqa
> +; CHECK: vpblendvb
> + %1 = select <32 x i1> <i1 false, i1 false, i1 true, i1 false, i1 true,
> i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1 true,
> i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1 true,
> i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1 true,
> i1 true, i1 true, i1 false>, <32 x i8> %xyzw, <32 x i8> %abcd
> + ret <32 x i8> %1
> +}
> +
> +declare <32 x i8> @llvm.x86.avx2.pblendvb(<32 x i8>, <32 x i8>, <32 x i8>)
>
> Modified: llvm/trunk/test/CodeGen/X86/sse41-blend.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/CodeGen/X86/sse41-blend.ll?rev=209643&r1=209642&r2=209643&view=diff
>
> ==============================================================================
> --- llvm/trunk/test/CodeGen/X86/sse41-blend.ll (original)
> +++ llvm/trunk/test/CodeGen/X86/sse41-blend.ll Mon May 26 22:42:20 2014
> @@ -88,3 +88,35 @@ entry:
> store double %extract214vector_func.i, double addrspace(1)* undef,
> align 8
> ret void
> }
> +
> +; If we can figure out a blend has a constant mask, we should emit the
> +; blend instruction with an immediate mask
> +define <2 x double> @constant_blendvpd(<2 x double> %xy, <2 x double>
> %ab) {
> +; In this case, we emit a simple movss
> +; CHECK-LABEL: constant_blendvpd
> +; CHECK: movsd
> +; CHECK: ret
> + %1 = select <2 x i1> <i1 true, i1 false>, <2 x double> %xy, <2 x
> double> %ab
> + ret <2 x double> %1
> +}
> +
> +define <4 x float> @constant_blendvps(<4 x float> %xyzw, <4 x float>
> %abcd) {
> +; CHECK-LABEL: constant_blendvps
> +; CHECK-NOT: mov
> +; CHECK: blendps $7
> +; CHECK: ret
> + %1 = select <4 x i1> <i1 false, i1 false, i1 false, i1 true>, <4 x
> float> %xyzw, <4 x float> %abcd
> + ret <4 x float> %1
> +}
> +
> +define <16 x i8> @constant_pblendvb(<16 x i8> %xyzw, <16 x i8> %abcd) {
> +; CHECK-LABEL: constant_pblendvb:
> +; CHECK: movaps
> +; CHECK: pblendvb
> +; CHECK: ret
> + %1 = select <16 x i1> <i1 false, i1 false, i1 true, i1 false, i1 true,
> i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1 true,
> i1 true, i1 true, i1 false>, <16 x i8> %xyzw, <16 x i8> %abcd
> + ret <16 x i8> %1
> +}
> +declare <16 x i8> @llvm.x86.sse41.pblendvb(<16 x i8>, <16 x i8>, <16 x
> i8>)
> +declare <4 x float> @llvm.x86.sse41.blendvps(<4 x float>, <4 x float>, <4
> x float>)
> +declare <2 x double> @llvm.x86.sse41.blendvpd(<2 x double>, <2 x double>,
> <2 x double>)
>
> Added: llvm/trunk/test/Transforms/InstCombine/blend_x86.ll
> URL:
> http://llvm.org/viewvc/llvm-project/llvm/trunk/test/Transforms/InstCombine/blend_x86.ll?rev=209643&view=auto
>
> ==============================================================================
> --- llvm/trunk/test/Transforms/InstCombine/blend_x86.ll (added)
> +++ llvm/trunk/test/Transforms/InstCombine/blend_x86.ll Mon May 26
> 22:42:20 2014
> @@ -0,0 +1,56 @@
> +; RUN: opt < %s -instcombine -mtriple=x86_64-apple-macosx -mcpu=core-avx2
> -S | FileCheck %s
> +
> +define <2 x double> @constant_blendvpd(<2 x double> %xy, <2 x double>
> %ab) {
> +; CHECK-LABEL: @constant_blendvpd
> +; CHECK: select <2 x i1> <i1 true, i1 false>
> + %1 = tail call <2 x double> @llvm.x86.sse41.blendvpd(<2 x double> %xy,
> <2 x double> %ab, <2 x double> <double 0xFFFFFFFFE0000000, double
> 0.000000e+00>)
> + ret <2 x double> %1
> +}
> +
> +define <4 x float> @constant_blendvps(<4 x float> %xyzw, <4 x float>
> %abcd) {
> +; CHECK-LABEL: @constant_blendvps
> +; CHECK: select <4 x i1> <i1 false, i1 false, i1 false, i1 true>
> + %1 = tail call <4 x float> @llvm.x86.sse41.blendvps(<4 x float> %xyzw,
> <4 x float> %abcd, <4 x float> <float 0.000000e+00, float 0.000000e+00,
> float 0.000000e+00, float 0xFFFFFFFFE0000000>)
> + ret <4 x float> %1
> +}
> +
> +define <16 x i8> @constant_pblendvb(<16 x i8> %xyzw, <16 x i8> %abcd) {
> +; CHECK-LABEL: @constant_pblendvb
> +; CHECK: select <16 x i1> <i1 false, i1 false, i1 true, i1 false, i1
> true, i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1
> true, i1 true, i1 true, i1 false>
> + %1 = tail call <16 x i8> @llvm.x86.sse41.pblendvb(<16 x i8> %xyzw, <16
> x i8> %abcd, <16 x i8> <i8 0, i8 0, i8 255, i8 0, i8 255, i8 255, i8 255,
> i8 0, i8 0, i8 0, i8 255, i8 0, i8 255, i8 255, i8 255, i8 0>)
> + ret <16 x i8> %1
> +}
> +
> +define <4 x double> @constant_blendvpd_avx(<4 x double> %xy, <4 x double>
> %ab) {
> +; CHECK-LABEL: @constant_blendvpd_avx
> +; CHECK: select <4 x i1> <i1 true, i1 false, i1 true, i1 false>
> + %1 = tail call <4 x double> @llvm.x86.avx.blendv.pd.256(<4 x double>
> %xy, <4 x double> %ab, <4 x double> <double 0xFFFFFFFFE0000000, double
> 0.000000e+00, double 0xFFFFFFFFE0000000, double 0.000000e+00>)
> + ret <4 x double> %1
> +}
> +
> +define <8 x float> @constant_blendvps_avx(<8 x float> %xyzw, <8 x float>
> %abcd) {
> +; CHECK-LABEL: @constant_blendvps_avx
> +; CHECK: select <8 x i1> <i1 false, i1 false, i1 false, i1 true, i1
> false, i1 false, i1 false, i1 true>
> + %1 = tail call <8 x float> @llvm.x86.avx.blendv.ps.256(<8 x float>
> %xyzw, <8 x float> %abcd, <8 x float> <float 0.000000e+00, float
> 0.000000e+00, float 0.000000e+00, float 0xFFFFFFFFE0000000, float
> 0.000000e+00, float 0.000000e+00, float 0.000000e+00, float
> 0xFFFFFFFFE0000000>)
> + ret <8 x float> %1
> +}
> +
> +define <32 x i8> @constant_pblendvb_avx2(<32 x i8> %xyzw, <32 x i8>
> %abcd) {
> +; CHECK-LABEL: @constant_pblendvb_avx2
> +; CHECK: select <32 x i1> <i1 false, i1 false, i1 true, i1 false, i1
> true, i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1
> true, i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1
> true, i1 true, i1 true, i1 false, i1 false, i1 false, i1 true, i1 false, i1
> true, i1 true, i1 true, i1 false>
> + %1 = tail call <32 x i8> @llvm.x86.avx2.pblendvb(<32 x i8> %xyzw, <32 x
> i8> %abcd,
> + <32 x i8> <i8 0, i8 0, i8 255, i8 0, i8 255, i8 255, i8 255, i8 0,
> + i8 0, i8 0, i8 255, i8 0, i8 255, i8 255, i8 255, i8 0,
> + i8 0, i8 0, i8 255, i8 0, i8 255, i8 255, i8 255, i8 0,
> + i8 0, i8 0, i8 255, i8 0, i8 255, i8 255, i8 255, i8
> 0>)
> + ret <32 x i8> %1
> +}
> +
> +declare <16 x i8> @llvm.x86.sse41.pblendvb(<16 x i8>, <16 x i8>, <16 x
> i8>)
> +declare <4 x float> @llvm.x86.sse41.blendvps(<4 x float>, <4 x float>, <4
> x float>)
> +declare <2 x double> @llvm.x86.sse41.blendvpd(<2 x double>, <2 x double>,
> <2 x double>)
> +
> +declare <32 x i8> @llvm.x86.avx2.pblendvb(<32 x i8>, <32 x i8>, <32 x i8>)
> +declare <8 x float> @llvm.x86.avx.blendv.ps.256(<8 x float>, <8 x float>,
> <8 x float>)
> +declare <4 x double> @llvm.x86.avx.blendv.pd.256(<4 x double>, <4 x
> double>, <4 x double>)
> +
>
>
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