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MSL: Fix generation of the WorkgroupSize built-in. #2491

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Merged
HansKristian-Work merged 1 commit into from
Jun 11, 2025
Merged

MSL: Fix generation of the WorkgroupSize built-in. #2491

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2 changes: 1 addition & 1 deletion ...at.invalid.vk.msl12.emulate-subgroup.comp → ...s.nocompat.vk.msl12.emulate-subgroup.comp
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Original file line number Diff line number Diff line change
Expand Up @@ -10,7 +10,7 @@ struct SSBO

constant uint3 gl_WorkGroupSize [[maybe_unused]] = uint3(1u);

kernel void main0(device SSBO& _9 [[buffer(0)]], uint gl_LocalInvocationIndex [[thread_index_in_threadgroup]], unsupported-built-in-type gl_WorkGroupSize [[unsupported-built-in]])
kernel void main0(device SSBO& _9 [[buffer(0)]], uint gl_LocalInvocationIndex [[thread_index_in_threadgroup]])
{
uint gl_NumSubgroups = gl_WorkGroupSize.x * gl_WorkGroupSize.y * gl_WorkGroupSize.z;
uint gl_SubgroupID = gl_LocalInvocationIndex;
Expand Down
0 ...at.invalid.vk.msl12.emulate-subgroup.comp → ...s.nocompat.vk.msl12.emulate-subgroup.comp
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72 changes: 53 additions & 19 deletions spirv_msl.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -510,7 +510,7 @@ void CompilerMSL::build_implicit_builtins()
has_local_invocation_index = true;
}

if (need_workgroup_size && builtin == BuiltInLocalInvocationId)
if (need_workgroup_size && builtin == BuiltInWorkgroupSize)
{
builtin_workgroup_size_id = var.self;
mark_implicit_builtin(StorageClassInput, BuiltInWorkgroupSize, var.self);
Expand Down Expand Up @@ -932,25 +932,55 @@ void CompilerMSL::build_implicit_builtins()

if (need_workgroup_size && !has_workgroup_size)
{
uint32_t offset = ir.increase_bound_by(2);
uint32_t type_ptr_id = offset;
uint32_t var_id = offset + 1;

// Create gl_WorkgroupSize.
uint32_t type_id = build_extended_vector_type(get_uint_type_id(), 3);
SPIRType uint_type_ptr = get<SPIRType>(type_id);
uint_type_ptr.op = OpTypePointer;
uint_type_ptr.pointer = true;
uint_type_ptr.pointer_depth++;
uint_type_ptr.parent_type = type_id;
uint_type_ptr.storage = StorageClassInput;
auto &execution = get_entry_point();
// First, check if the workgroup size _constant_ were defined.
// If it were, we don't need to do--in fact, shouldn't do--anything.
builtin_workgroup_size_id = execution.workgroup_size.constant;
if (builtin_workgroup_size_id == 0)
{
uint32_t var_id = ir.increase_bound_by(1);

auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
ptr_type.self = type_id;
set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
set_decoration(var_id, DecorationBuiltIn, BuiltInWorkgroupSize);
builtin_workgroup_size_id = var_id;
mark_implicit_builtin(StorageClassInput, BuiltInWorkgroupSize, var_id);
// Create gl_WorkgroupSize.
uint32_t type_id = build_extended_vector_type(get_uint_type_id(), 3);
// If we have LocalSize or LocalSizeId, use those to define the workgroup size.
if (execution.flags.get(ExecutionModeLocalSizeId))
{
const SPIRConstant *init[] = { &get<SPIRConstant>(execution.workgroup_size.id_x),
&get<SPIRConstant>(execution.workgroup_size.id_y),
&get<SPIRConstant>(execution.workgroup_size.id_z) };
bool specialized = init[0]->specialization || init[1]->specialization || init[2]->specialization;
set<SPIRConstant>(var_id, type_id, init, 3, specialized);
execution.workgroup_size.constant = var_id;
}
else if (execution.flags.get(ExecutionModeLocalSize))
{
uint32_t offset = ir.increase_bound_by(3);
const SPIRConstant *init[] = {
&set<SPIRConstant>(offset, get_uint_type_id(), execution.workgroup_size.x, false),
&set<SPIRConstant>(offset + 1, get_uint_type_id(), execution.workgroup_size.y, false),
&set<SPIRConstant>(offset + 2, get_uint_type_id(), execution.workgroup_size.z, false)
};
set<SPIRConstant>(var_id, type_id, init, 3, false);
execution.workgroup_size.constant = var_id;
}
else
{
uint32_t type_ptr_id = ir.increase_bound_by(1);
SPIRType uint_type_ptr = get<SPIRType>(type_id);
uint_type_ptr.op = OpTypePointer;
uint_type_ptr.pointer = true;
uint_type_ptr.pointer_depth++;
uint_type_ptr.parent_type = type_id;
uint_type_ptr.storage = StorageClassInput;

auto &ptr_type = set<SPIRType>(type_ptr_id, uint_type_ptr);
ptr_type.self = type_id;
set<SPIRVariable>(var_id, type_ptr_id, StorageClassInput);
mark_implicit_builtin(StorageClassInput, BuiltInWorkgroupSize, var_id);
}
set_decoration(var_id, DecorationBuiltIn, BuiltInWorkgroupSize);
builtin_workgroup_size_id = var_id;
}
}

if (!has_frag_depth && force_frag_depth_passthrough)
Expand Down Expand Up @@ -17679,6 +17709,9 @@ string CompilerMSL::builtin_qualifier(BuiltIn builtin)
case BuiltInGlobalInvocationId:
return "thread_position_in_grid";

case BuiltInWorkgroupSize:
return "threads_per_threadgroup";

case BuiltInWorkgroupId:
return "threadgroup_position_in_grid";

Expand Down Expand Up @@ -17864,6 +17897,7 @@ string CompilerMSL::builtin_type_decl(BuiltIn builtin, uint32_t id)
case BuiltInLocalInvocationId:
case BuiltInNumWorkgroups:
case BuiltInWorkgroupId:
case BuiltInWorkgroupSize:
return "uint3";
case BuiltInLocalInvocationIndex:
case BuiltInNumSubgroups:
Expand Down