[PATCH] DAGCombiner: Pass the correct type to TargetLowering::isF(Abs|Neg)Free

Tom Stellard tom at stellard.net
Fri Jul 19 10:32:55 PDT 2013


Ping.

On Tue, Jul 16, 2013 at 04:25:59PM -0700, Tom Stellard wrote:
> From: Tom Stellard <thomas.stellard at amd.com>
> 
> This commit also implements these functions for R600 and removes a test
> case that was relying on the buggy behavior.
> ---
>  include/llvm/Target/TargetLowering.h     |   6 +-
>  lib/CodeGen/SelectionDAG/DAGCombiner.cpp |   4 +-
>  lib/Target/R600/AMDGPUISelLowering.cpp   |  14 +++
>  lib/Target/R600/AMDGPUISelLowering.h     |   3 +
>  test/CodeGen/R600/fabs.ll                |  28 ++++--
>  test/CodeGen/R600/fneg.ll                |  16 +++
>  test/CodeGen/R600/literals.ll            | 166 -------------------------------
>  7 files changed, 56 insertions(+), 181 deletions(-)
>  create mode 100644 test/CodeGen/R600/fneg.ll
> 
> diff --git a/include/llvm/Target/TargetLowering.h b/include/llvm/Target/TargetLowering.h
> index 09a93f9..2a383e4 100644
> --- a/include/llvm/Target/TargetLowering.h
> +++ b/include/llvm/Target/TargetLowering.h
> @@ -1174,13 +1174,15 @@ public:
>  
>    /// Return true if an fneg operation is free to the point where it is never
>    /// worthwhile to replace it with a bitwise operation.
> -  virtual bool isFNegFree(EVT) const {
> +  virtual bool isFNegFree(EVT VT) const {
> +    assert(VT.isFloatingPoint());
>      return false;
>    }
>  
>    /// Return true if an fneg operation is free to the point where it is never
>    /// worthwhile to replace it with a bitwise operation.
> -  virtual bool isFAbsFree(EVT) const {
> +  virtual bool isFAbsFree(EVT VT) const {
> +    assert(VT.isFloatingPoint());
>      return false;
>    }
>  
> diff --git a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
> index 111803f..ac4eeaf 100644
> --- a/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
> +++ b/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
> @@ -5680,8 +5680,8 @@ SDValue DAGCombiner::visitBITCAST(SDNode *N) {
>    // fold (bitconvert (fneg x)) -> (xor (bitconvert x), signbit)
>    // fold (bitconvert (fabs x)) -> (and (bitconvert x), (not signbit))
>    // This often reduces constant pool loads.
> -  if (((N0.getOpcode() == ISD::FNEG && !TLI.isFNegFree(VT)) ||
> -       (N0.getOpcode() == ISD::FABS && !TLI.isFAbsFree(VT))) &&
> +  if (((N0.getOpcode() == ISD::FNEG && !TLI.isFNegFree(N0.getValueType())) ||
> +       (N0.getOpcode() == ISD::FABS && !TLI.isFAbsFree(N0.getValueType()))) &&
>        N0.getNode()->hasOneUse() && VT.isInteger() &&
>        !VT.isVector() && !N0.getValueType().isVector()) {
>      SDValue NewConv = DAG.getNode(ISD::BITCAST, SDLoc(N0), VT,
> diff --git a/lib/Target/R600/AMDGPUISelLowering.cpp b/lib/Target/R600/AMDGPUISelLowering.cpp
> index dcf0f56..3342a8d 100644
> --- a/lib/Target/R600/AMDGPUISelLowering.cpp
> +++ b/lib/Target/R600/AMDGPUISelLowering.cpp
> @@ -103,6 +103,20 @@ AMDGPUTargetLowering::AMDGPUTargetLowering(TargetMachine &TM) :
>  }
>  
>  //===---------------------------------------------------------------------===//
> +// Target Properties
> +//===---------------------------------------------------------------------===//
> +
> +bool AMDGPUTargetLowering::isFAbsFree(EVT VT) const {
> +  assert(VT.isFloatingPoint());
> +  return VT == MVT::f32;
> +}
> +
> +bool AMDGPUTargetLowering::isFNegFree(EVT VT) const {
> +  assert(VT.isFloatingPoint());
> +  return VT == MVT::f32;
> +}
> +
> +//===---------------------------------------------------------------------===//
>  // TargetLowering Callbacks
>  //===---------------------------------------------------------------------===//
>  
> diff --git a/lib/Target/R600/AMDGPUISelLowering.h b/lib/Target/R600/AMDGPUISelLowering.h
> index 7f4468c..0e1c131 100644
> --- a/lib/Target/R600/AMDGPUISelLowering.h
> +++ b/lib/Target/R600/AMDGPUISelLowering.h
> @@ -49,6 +49,9 @@ protected:
>  public:
>    AMDGPUTargetLowering(TargetMachine &TM);
>  
> +  virtual bool isFAbsFree(EVT VT) const;
> +  virtual bool isFNegFree(EVT VT) const;
> +
>    virtual SDValue LowerReturn(SDValue Chain, CallingConv::ID CallConv,
>                                bool isVarArg,
>                                const SmallVectorImpl<ISD::OutputArg> &Outs,
> diff --git a/test/CodeGen/R600/fabs.ll b/test/CodeGen/R600/fabs.ll
> index 85f2882..78ffd57 100644
> --- a/test/CodeGen/R600/fabs.ll
> +++ b/test/CodeGen/R600/fabs.ll
> @@ -1,16 +1,22 @@
> -;RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
> +; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s --check-prefix=R600-CHECK
> +; RUN: llc < %s -march=r600 -mcpu=SI | FileCheck %s --check-prefix=SI-CHECK
>  
> -;CHECK: MOV * T{{[0-9]+\.[XYZW], \|T[0-9]+\.[XYZW]\|}}
> +; DAGCombiner will transform:
> +; (fabs (f32 bitcast (i32 a))) => (f32 bitcast (and (i32 a), 0x7FFFFFFF))
> +; unless isFabsFree returns true
>  
> -define void @test() {
> -   %r0 = call float @llvm.R600.load.input(i32 0)
> -   %r1 = call float @fabs( float %r0)
> -   call void @llvm.AMDGPU.store.output(float %r1, i32 0)
> -   ret void
> -}
> -
> -declare float @llvm.R600.load.input(i32) readnone
> +; R600-CHECK: @fabs_free
> +; R600-CHECK-NOT: AND
> +; R600-CHECK: |PV.{{[XYZW]}}|
> +; SI-CHECK: @fabs_free
> +; SI-CHECK: V_ADD_F32_e64 VGPR{{[0-9]}}, SGPR{{[0-9]}}, 0, 1, 0, 0, 0
>  
> -declare void @llvm.AMDGPU.store.output(float, i32)
> +define void @fabs_free(float addrspace(1)* %out, i32 %in) {
> +entry:
> +  %0 = bitcast i32 %in to float
> +  %1 = call float @fabs(float %0)
> +  store float %1, float addrspace(1)* %out
> +  ret void
> +}
>  
>  declare float @fabs(float ) readnone
> diff --git a/test/CodeGen/R600/fneg.ll b/test/CodeGen/R600/fneg.ll
> new file mode 100644
> index 0000000..343e296
> --- /dev/null
> +++ b/test/CodeGen/R600/fneg.ll
> @@ -0,0 +1,16 @@
> +; RUN: llc < %s -march=r600 -mcpu=redwood | FileCheck %s
> +
> +; DAGCombiner will transform:
> +; (fneg (f32 bitcast (i32 a))) => (f32 bitcast (xor (i32 a), 0x80000000))
> +; unless the target returns true for isNegFree()
> +
> +; CHECK-NOT: XOR
> +; CHECK: -KC0[2].Z
> +
> +define void @fneg_free(float addrspace(1)* %out, i32 %in) {
> +entry:
> +  %0 = bitcast i32 %in to float
> +  %1 = fsub float 0.0, %0
> +  store float %1, float addrspace(1)* %out
> +  ret void
> +}
> diff --git a/test/CodeGen/R600/literals.ll b/test/CodeGen/R600/literals.ll
> index fbb77b3..77b168e 100644
> --- a/test/CodeGen/R600/literals.ll
> +++ b/test/CodeGen/R600/literals.ll
> @@ -31,169 +31,3 @@ entry:
>    store float %0, float addrspace(1)* %out
>    ret void
>  }
> -
> -; CHECK: @main
> -; CHECK: -2147483648
> -; CHECK-NEXT-NOT: -2147483648
> -
> -define void @main() #0 {
> -main_body:
> -  %0 = call float @llvm.R600.load.input(i32 4)
> -  %1 = call float @llvm.R600.load.input(i32 5)
> -  %2 = call float @llvm.R600.load.input(i32 6)
> -  %3 = call float @llvm.R600.load.input(i32 7)
> -  %4 = call float @llvm.R600.load.input(i32 8)
> -  %5 = call float @llvm.R600.load.input(i32 9)
> -  %6 = call float @llvm.R600.load.input(i32 10)
> -  %7 = call float @llvm.R600.load.input(i32 11)
> -  %8 = call float @llvm.R600.load.input(i32 12)
> -  %9 = call float @llvm.R600.load.input(i32 13)
> -  %10 = call float @llvm.R600.load.input(i32 14)
> -  %11 = call float @llvm.R600.load.input(i32 15)
> -  %12 = load <4 x float> addrspace(8)* null
> -  %13 = extractelement <4 x float> %12, i32 0
> -  %14 = fsub float -0.000000e+00, %13
> -  %15 = fadd float %0, %14
> -  %16 = load <4 x float> addrspace(8)* null
> -  %17 = extractelement <4 x float> %16, i32 1
> -  %18 = fsub float -0.000000e+00, %17
> -  %19 = fadd float %1, %18
> -  %20 = load <4 x float> addrspace(8)* null
> -  %21 = extractelement <4 x float> %20, i32 2
> -  %22 = fsub float -0.000000e+00, %21
> -  %23 = fadd float %2, %22
> -  %24 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 1)
> -  %25 = extractelement <4 x float> %24, i32 0
> -  %26 = fmul float %25, %0
> -  %27 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 1)
> -  %28 = extractelement <4 x float> %27, i32 1
> -  %29 = fmul float %28, %0
> -  %30 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 1)
> -  %31 = extractelement <4 x float> %30, i32 2
> -  %32 = fmul float %31, %0
> -  %33 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 1)
> -  %34 = extractelement <4 x float> %33, i32 3
> -  %35 = fmul float %34, %0
> -  %36 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 2)
> -  %37 = extractelement <4 x float> %36, i32 0
> -  %38 = fmul float %37, %1
> -  %39 = fadd float %38, %26
> -  %40 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 2)
> -  %41 = extractelement <4 x float> %40, i32 1
> -  %42 = fmul float %41, %1
> -  %43 = fadd float %42, %29
> -  %44 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 2)
> -  %45 = extractelement <4 x float> %44, i32 2
> -  %46 = fmul float %45, %1
> -  %47 = fadd float %46, %32
> -  %48 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 2)
> -  %49 = extractelement <4 x float> %48, i32 3
> -  %50 = fmul float %49, %1
> -  %51 = fadd float %50, %35
> -  %52 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 3)
> -  %53 = extractelement <4 x float> %52, i32 0
> -  %54 = fmul float %53, %2
> -  %55 = fadd float %54, %39
> -  %56 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 3)
> -  %57 = extractelement <4 x float> %56, i32 1
> -  %58 = fmul float %57, %2
> -  %59 = fadd float %58, %43
> -  %60 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 3)
> -  %61 = extractelement <4 x float> %60, i32 2
> -  %62 = fmul float %61, %2
> -  %63 = fadd float %62, %47
> -  %64 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 3)
> -  %65 = extractelement <4 x float> %64, i32 3
> -  %66 = fmul float %65, %2
> -  %67 = fadd float %66, %51
> -  %68 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 4)
> -  %69 = extractelement <4 x float> %68, i32 0
> -  %70 = fmul float %69, %3
> -  %71 = fadd float %70, %55
> -  %72 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 4)
> -  %73 = extractelement <4 x float> %72, i32 1
> -  %74 = fmul float %73, %3
> -  %75 = fadd float %74, %59
> -  %76 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 4)
> -  %77 = extractelement <4 x float> %76, i32 2
> -  %78 = fmul float %77, %3
> -  %79 = fadd float %78, %63
> -  %80 = load <4 x float> addrspace(8)* getelementptr ([1024 x <4 x float>] addrspace(8)* null, i64 0, i32 4)
> -  %81 = extractelement <4 x float> %80, i32 3
> -  %82 = fmul float %81, %3
> -  %83 = fadd float %82, %67
> -  %84 = insertelement <4 x float> undef, float %15, i32 0
> -  %85 = insertelement <4 x float> %84, float %19, i32 1
> -  %86 = insertelement <4 x float> %85, float %23, i32 2
> -  %87 = insertelement <4 x float> %86, float 0.000000e+00, i32 3
> -  %88 = insertelement <4 x float> undef, float %15, i32 0
> -  %89 = insertelement <4 x float> %88, float %19, i32 1
> -  %90 = insertelement <4 x float> %89, float %23, i32 2
> -  %91 = insertelement <4 x float> %90, float 0.000000e+00, i32 3
> -  %92 = call float @llvm.AMDGPU.dp4(<4 x float> %87, <4 x float> %91)
> -  %93 = call float @fabs(float %92)
> -  %94 = call float @llvm.AMDGPU.rsq(float %93)
> -  %95 = fmul float %15, %94
> -  %96 = fmul float %19, %94
> -  %97 = fmul float %23, %94
> -  %98 = insertelement <4 x float> undef, float %4, i32 0
> -  %99 = insertelement <4 x float> %98, float %5, i32 1
> -  %100 = insertelement <4 x float> %99, float %6, i32 2
> -  %101 = insertelement <4 x float> %100, float 0.000000e+00, i32 3
> -  %102 = insertelement <4 x float> undef, float %4, i32 0
> -  %103 = insertelement <4 x float> %102, float %5, i32 1
> -  %104 = insertelement <4 x float> %103, float %6, i32 2
> -  %105 = insertelement <4 x float> %104, float 0.000000e+00, i32 3
> -  %106 = call float @llvm.AMDGPU.dp4(<4 x float> %101, <4 x float> %105)
> -  %107 = call float @fabs(float %106)
> -  %108 = call float @llvm.AMDGPU.rsq(float %107)
> -  %109 = fmul float %4, %108
> -  %110 = fmul float %5, %108
> -  %111 = fmul float %6, %108
> -  %112 = insertelement <4 x float> undef, float %95, i32 0
> -  %113 = insertelement <4 x float> %112, float %96, i32 1
> -  %114 = insertelement <4 x float> %113, float %97, i32 2
> -  %115 = insertelement <4 x float> %114, float 0.000000e+00, i32 3
> -  %116 = insertelement <4 x float> undef, float %109, i32 0
> -  %117 = insertelement <4 x float> %116, float %110, i32 1
> -  %118 = insertelement <4 x float> %117, float %111, i32 2
> -  %119 = insertelement <4 x float> %118, float 0.000000e+00, i32 3
> -  %120 = call float @llvm.AMDGPU.dp4(<4 x float> %115, <4 x float> %119)
> -  %121 = fsub float -0.000000e+00, %120
> -  %122 = fcmp uge float 0.000000e+00, %121
> -  %123 = select i1 %122, float 0.000000e+00, float %121
> -  %124 = insertelement <4 x float> undef, float %8, i32 0
> -  %125 = insertelement <4 x float> %124, float %9, i32 1
> -  %126 = insertelement <4 x float> %125, float 5.000000e-01, i32 2
> -  %127 = insertelement <4 x float> %126, float 1.000000e+00, i32 3
> -  call void @llvm.R600.store.swizzle(<4 x float> %127, i32 60, i32 1)
> -  %128 = insertelement <4 x float> undef, float %71, i32 0
> -  %129 = insertelement <4 x float> %128, float %75, i32 1
> -  %130 = insertelement <4 x float> %129, float %79, i32 2
> -  %131 = insertelement <4 x float> %130, float %83, i32 3
> -  call void @llvm.R600.store.swizzle(<4 x float> %131, i32 0, i32 2)
> -  %132 = insertelement <4 x float> undef, float %123, i32 0
> -  %133 = insertelement <4 x float> %132, float %96, i32 1
> -  %134 = insertelement <4 x float> %133, float %97, i32 2
> -  %135 = insertelement <4 x float> %134, float 0.000000e+00, i32 3
> -  call void @llvm.R600.store.swizzle(<4 x float> %135, i32 1, i32 2)
> -  ret void
> -}
> -
> -; Function Attrs: readnone
> -declare float @llvm.R600.load.input(i32) #1
> -
> -; Function Attrs: readnone
> -declare float @llvm.AMDGPU.dp4(<4 x float>, <4 x float>) #1
> -
> -; Function Attrs: readonly
> -declare float @fabs(float) #2
> -
> -; Function Attrs: readnone
> -declare float @llvm.AMDGPU.rsq(float) #1
> -
> -declare void @llvm.R600.store.swizzle(<4 x float>, i32, i32)
> -
> -attributes #0 = { "ShaderType"="1" }
> -attributes #1 = { readnone }
> -attributes #2 = { readonly }
> -- 
> 1.7.11.4
> 
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