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Legalization of Workgroup function parameter #2430

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#2434
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Legalization of Workgroup function parameter#2430
#2434
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s-perron
@ehsannas

Description

@ehsannas
ehsannas
opened on Mar 7, 2019

We are wondering whether spirv-opt can legalize/optimize the following scenario.

We have this sample HLSL shader:

struct testStruct {
	float Data[10][10];
};

float testFunc(testStruct t, uint topLeftX, uint topLeftY) {
  t.Data[0][0] = 2.0f * t.Data[0][0];
  return t.Data[0][0];
}
  
groupshared testStruct sharedStruct;

RWStructuredBuffer<float> testOut;

[numthreads(8, 8, 1)]
void testMain( uint3 DispatchThreadId	: SV_DispatchThreadID, uint3 GroupThreadID : SV_GroupThreadID, uint3 GroupID : SV_GroupID ) {
    float result = testFunc(sharedStruct, GroupThreadID.x, GroupThreadID.y);
    testOut[GroupThreadID.x] = result;
}

Which DXC compiles to the following SPIR-V (without legalization, without optimization):

; SPIR-V
; Version: 1.0
; Generator: Google spiregg; 0
; Bound: 71
; Schema: 0
               OpCapability Shader
               OpMemoryModel Logical GLSL450
               OpEntryPoint GLCompute %testMain "testMain" %gl_GlobalInvocationID %gl_LocalInvocationID %gl_WorkGroupID
               OpExecutionMode %testMain LocalSize 8 8 1
               OpSource HLSL 600
               OpName %testStruct "testStruct"
               OpMemberName %testStruct 0 "Data"
               OpName %sharedStruct "sharedStruct"
               OpName %type_RWStructuredBuffer_float "type.RWStructuredBuffer.float"
               OpName %testOut "testOut"
               OpName %type_ACSBuffer_counter "type.ACSBuffer.counter"
               OpMemberName %type_ACSBuffer_counter 0 "counter"
               OpName %counter_var_testOut "counter.var.testOut"
               OpName %testMain "testMain"
               OpName %param_var_DispatchThreadId "param.var.DispatchThreadId"
               OpName %param_var_GroupThreadID "param.var.GroupThreadID"
               OpName %param_var_GroupID "param.var.GroupID"
               OpName %src_testMain "src.testMain"
               OpName %DispatchThreadId "DispatchThreadId"
               OpName %GroupThreadID "GroupThreadID"
               OpName %GroupID "GroupID"
               OpName %bb_entry "bb.entry"
               OpName %result "result"
               OpName %param_var_topLeftX "param.var.topLeftX"
               OpName %param_var_topLeftY "param.var.topLeftY"
               OpName %testFunc "testFunc"
               OpName %t "t"
               OpName %topLeftX "topLeftX"
               OpName %topLeftY "topLeftY"
               OpName %bb_entry_0 "bb.entry"
               OpDecorate %gl_GlobalInvocationID BuiltIn GlobalInvocationId
               OpDecorate %gl_LocalInvocationID BuiltIn LocalInvocationId
               OpDecorate %gl_WorkGroupID BuiltIn WorkgroupId
               OpDecorate %testOut DescriptorSet 0
               OpDecorate %testOut Binding 0
               OpDecorate %counter_var_testOut DescriptorSet 0
               OpDecorate %counter_var_testOut Binding 1
               OpDecorate %_runtimearr_float ArrayStride 4
               OpMemberDecorate %type_RWStructuredBuffer_float 0 Offset 0
               OpDecorate %type_RWStructuredBuffer_float BufferBlock
               OpMemberDecorate %type_ACSBuffer_counter 0 Offset 0
               OpDecorate %type_ACSBuffer_counter BufferBlock
        %int = OpTypeInt 32 1
      %int_0 = OpConstant %int 0
      %int_1 = OpConstant %int 1
      %float = OpTypeFloat 32
    %float_2 = OpConstant %float 2
       %uint = OpTypeInt 32 0
    %uint_10 = OpConstant %uint 10
%_arr_float_uint_10 = OpTypeArray %float %uint_10
%_arr__arr_float_uint_10_uint_10 = OpTypeArray %_arr_float_uint_10 %uint_10
 %testStruct = OpTypeStruct %_arr__arr_float_uint_10_uint_10
%_ptr_Workgroup_testStruct = OpTypePointer Workgroup %testStruct
%_runtimearr_float = OpTypeRuntimeArray %float
%type_RWStructuredBuffer_float = OpTypeStruct %_runtimearr_float
%_ptr_Uniform_type_RWStructuredBuffer_float = OpTypePointer Uniform %type_RWStructuredBuffer_float
%type_ACSBuffer_counter = OpTypeStruct %int
%_ptr_Uniform_type_ACSBuffer_counter = OpTypePointer Uniform %type_ACSBuffer_counter
     %v3uint = OpTypeVector %uint 3
%_ptr_Input_v3uint = OpTypePointer Input %v3uint
       %void = OpTypeVoid
         %27 = OpTypeFunction %void
%_ptr_Function_v3uint = OpTypePointer Function %v3uint
         %38 = OpTypeFunction %void %_ptr_Function_v3uint %_ptr_Function_v3uint %_ptr_Function_v3uint
%_ptr_Function_float = OpTypePointer Function %float
%_ptr_Function_uint = OpTypePointer Function %uint
%_ptr_Uniform_float = OpTypePointer Uniform %float
%_ptr_Function_testStruct = OpTypePointer Function %testStruct
         %59 = OpTypeFunction %float %_ptr_Function_testStruct %_ptr_Function_uint %_ptr_Function_uint
%sharedStruct = OpVariable %_ptr_Workgroup_testStruct Workgroup
    %testOut = OpVariable %_ptr_Uniform_type_RWStructuredBuffer_float Uniform
%counter_var_testOut = OpVariable %_ptr_Uniform_type_ACSBuffer_counter Uniform
%gl_GlobalInvocationID = OpVariable %_ptr_Input_v3uint Input
%gl_LocalInvocationID = OpVariable %_ptr_Input_v3uint Input
%gl_WorkGroupID = OpVariable %_ptr_Input_v3uint Input
   %testMain = OpFunction %void None %27
         %28 = OpLabel
%param_var_DispatchThreadId = OpVariable %_ptr_Function_v3uint Function
%param_var_GroupThreadID = OpVariable %_ptr_Function_v3uint Function
%param_var_GroupID = OpVariable %_ptr_Function_v3uint Function
         %33 = OpLoad %v3uint %gl_GlobalInvocationID
         %34 = OpLoad %v3uint %gl_LocalInvocationID
               OpStore %param_var_GroupThreadID %34
         %35 = OpLoad %v3uint %gl_WorkGroupID
         %36 = OpFunctionCall %void %src_testMain %param_var_DispatchThreadId %param_var_GroupThreadID %param_var_GroupID
               OpReturn
               OpFunctionEnd
%src_testMain = OpFunction %void None %38
%DispatchThreadId = OpFunctionParameter %_ptr_Function_v3uint
%GroupThreadID = OpFunctionParameter %_ptr_Function_v3uint
    %GroupID = OpFunctionParameter %_ptr_Function_v3uint
   %bb_entry = OpLabel
     %result = OpVariable %_ptr_Function_float Function
%param_var_topLeftX = OpVariable %_ptr_Function_uint Function
%param_var_topLeftY = OpVariable %_ptr_Function_uint Function
         %48 = OpAccessChain %_ptr_Function_uint %GroupThreadID %int_0
         %49 = OpLoad %uint %48
               OpStore %param_var_topLeftX %49
         %50 = OpAccessChain %_ptr_Function_uint %GroupThreadID %int_1
         %51 = OpLoad %uint %50
               OpStore %param_var_topLeftY %51
         %52 = OpFunctionCall %float %testFunc %sharedStruct %param_var_topLeftX %param_var_topLeftY
               OpStore %result %52
         %54 = OpLoad %float %result
         %55 = OpAccessChain %_ptr_Function_uint %GroupThreadID %int_0
         %56 = OpLoad %uint %55
         %58 = OpAccessChain %_ptr_Uniform_float %testOut %int_0 %56
               OpStore %58 %54
               OpReturn
               OpFunctionEnd
   %testFunc = OpFunction %float None %59
          %t = OpFunctionParameter %_ptr_Function_testStruct
   %topLeftX = OpFunctionParameter %_ptr_Function_uint
   %topLeftY = OpFunctionParameter %_ptr_Function_uint
 %bb_entry_0 = OpLabel
         %65 = OpAccessChain %_ptr_Function_float %t %int_0 %int_0 %int_0
         %66 = OpLoad %float %65
         %67 = OpFMul %float %float_2 %66
         %68 = OpAccessChain %_ptr_Function_float %t %int_0 %int_0 %int_0
               OpStore %68 %67
         %69 = OpAccessChain %_ptr_Function_float %t %int_0 %int_0 %int_0
         %70 = OpLoad %float %69
               OpReturnValue %70
               OpFunctionEnd

This is illegal as the validator points out:

OpFunctionCall Argument <id> '18[%sharedStruct]'s type does not match Function <id> '60[%_ptr_Function_testStruct]'s parameter type.
  %52 = OpFunctionCall %float %testFunc %sharedStruct %param_var_topLeftX %param_var_topLeftY

After running legalization and optimization, we get:

; SPIR-V
; Version: 1.0
; Generator: Google spiregg; 0
; Bound: 34
; Schema: 0
               OpCapability Shader
               OpMemoryModel Logical GLSL450
               OpEntryPoint GLCompute %testMain "testMain" %gl_GlobalInvocationID %gl_LocalInvocationID %gl_WorkGroupID
               OpExecutionMode %testMain LocalSize 8 8 1
               OpSource HLSL 600
               OpName %testStruct "testStruct"
               OpMemberName %testStruct 0 "Data"
               OpName %sharedStruct "sharedStruct"
               OpName %type_RWStructuredBuffer_float "type.RWStructuredBuffer.float"
               OpName %testOut "testOut"
               OpName %testMain "testMain"
               OpDecorate %gl_GlobalInvocationID BuiltIn GlobalInvocationId
               OpDecorate %gl_LocalInvocationID BuiltIn LocalInvocationId
               OpDecorate %gl_WorkGroupID BuiltIn WorkgroupId
               OpDecorate %testOut DescriptorSet 0
               OpDecorate %testOut Binding 0
               OpDecorate %_runtimearr_float ArrayStride 4
               OpMemberDecorate %type_RWStructuredBuffer_float 0 Offset 0
               OpDecorate %type_RWStructuredBuffer_float BufferBlock
        %int = OpTypeInt 32 1
      %int_0 = OpConstant %int 0
      %float = OpTypeFloat 32
    %float_2 = OpConstant %float 2
       %uint = OpTypeInt 32 0
    %uint_10 = OpConstant %uint 10
%_arr_float_uint_10 = OpTypeArray %float %uint_10
%_arr__arr_float_uint_10_uint_10 = OpTypeArray %_arr_float_uint_10 %uint_10
 %testStruct = OpTypeStruct %_arr__arr_float_uint_10_uint_10
%_ptr_Workgroup_testStruct = OpTypePointer Workgroup %testStruct
%_runtimearr_float = OpTypeRuntimeArray %float
%type_RWStructuredBuffer_float = OpTypeStruct %_runtimearr_float
%_ptr_Uniform_type_RWStructuredBuffer_float = OpTypePointer Uniform %type_RWStructuredBuffer_float
     %v3uint = OpTypeVector %uint 3
%_ptr_Input_v3uint = OpTypePointer Input %v3uint
       %void = OpTypeVoid
         %23 = OpTypeFunction %void
%_ptr_Function_float = OpTypePointer Function %float
%_ptr_Uniform_float = OpTypePointer Uniform %float
%sharedStruct = OpVariable %_ptr_Workgroup_testStruct Workgroup
    %testOut = OpVariable %_ptr_Uniform_type_RWStructuredBuffer_float Uniform
%gl_GlobalInvocationID = OpVariable %_ptr_Input_v3uint Input
%gl_LocalInvocationID = OpVariable %_ptr_Input_v3uint Input
%gl_WorkGroupID = OpVariable %_ptr_Input_v3uint Input
   %testMain = OpFunction %void None %23
         %26 = OpLabel
         %27 = OpLoad %v3uint %gl_LocalInvocationID
         %28 = OpAccessChain %_ptr_Function_float %sharedStruct %int_0 %int_0 %int_0
         %29 = OpLoad %float %28
         %30 = OpFMul %float %float_2 %29
               OpStore %28 %30
         %31 = OpLoad %float %28
         %32 = OpCompositeExtract %uint %27 0
         %33 = OpAccessChain %_ptr_Uniform_float %testOut %int_0 %32
               OpStore %33 %31
               OpReturn
               OpFunctionEnd

Which is still illegal:

The result pointer storage class and base pointer storage class in OpAccessChain do not match.
  %28 = OpAccessChain %_ptr_Function_float %sharedStruct %int_0 %int_0 %int_0

The HLSL->SPIRV compilation for this example was done using the code in this PR.

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