Alexander Johnston 76f1949cfa
[HLSL] Implement the fwidth intrinsic for DXIL and SPIR-V target (#161378)
Adds the fwidth intrinsic for HLSL.
The DXIL path only requires modification to the hlsl headers.
The SPIRV path implements the OpFwidth builtin in Clang and instruction
selection for the OpFwidth instruction in LLVM.
Also adds shader stage tests to the ddx_coarse and ddy_coarse
instructions used by fwidth.

Closes #99120

---------

Co-authored-by: Alexander Johnston <alexander.johnston@amd.com>
2025-11-20 07:38:32 -05:00

162 lines
7.3 KiB
C++

//===--------- SPIR.cpp - Emit LLVM Code for builtins ---------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This contains code to emit Builtin calls as LLVM code.
//
//===----------------------------------------------------------------------===//
#include "CGHLSLRuntime.h"
#include "CodeGenFunction.h"
#include "clang/Basic/TargetBuiltins.h"
#include "llvm/IR/Intrinsics.h"
using namespace clang;
using namespace CodeGen;
using namespace llvm;
Value *CodeGenFunction::EmitSPIRVBuiltinExpr(unsigned BuiltinID,
const CallExpr *E) {
switch (BuiltinID) {
case SPIRV::BI__builtin_spirv_distance: {
Value *X = EmitScalarExpr(E->getArg(0));
Value *Y = EmitScalarExpr(E->getArg(1));
assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
E->getArg(1)->getType()->hasFloatingRepresentation() &&
"Distance operands must have a float representation");
assert(E->getArg(0)->getType()->isVectorType() &&
E->getArg(1)->getType()->isVectorType() &&
"Distance operands must be a vector");
return Builder.CreateIntrinsic(
/*ReturnType=*/X->getType()->getScalarType(), Intrinsic::spv_distance,
ArrayRef<Value *>{X, Y}, nullptr, "spv.distance");
}
case SPIRV::BI__builtin_spirv_length: {
Value *X = EmitScalarExpr(E->getArg(0));
assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
"length operand must have a float representation");
assert(E->getArg(0)->getType()->isVectorType() &&
"length operand must be a vector");
return Builder.CreateIntrinsic(
/*ReturnType=*/X->getType()->getScalarType(), Intrinsic::spv_length,
ArrayRef<Value *>{X}, nullptr, "spv.length");
}
case SPIRV::BI__builtin_spirv_reflect: {
Value *I = EmitScalarExpr(E->getArg(0));
Value *N = EmitScalarExpr(E->getArg(1));
assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
E->getArg(1)->getType()->hasFloatingRepresentation() &&
"Reflect operands must have a float representation");
assert(E->getArg(0)->getType()->isVectorType() &&
E->getArg(1)->getType()->isVectorType() &&
"Reflect operands must be a vector");
return Builder.CreateIntrinsic(
/*ReturnType=*/I->getType(), Intrinsic::spv_reflect,
ArrayRef<Value *>{I, N}, nullptr, "spv.reflect");
}
case SPIRV::BI__builtin_spirv_refract: {
Value *I = EmitScalarExpr(E->getArg(0));
Value *N = EmitScalarExpr(E->getArg(1));
Value *eta = EmitScalarExpr(E->getArg(2));
assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
E->getArg(1)->getType()->hasFloatingRepresentation() &&
E->getArg(2)->getType()->isFloatingType() &&
"refract operands must have a float representation");
return Builder.CreateIntrinsic(
/*ReturnType=*/I->getType(), Intrinsic::spv_refract,
ArrayRef<Value *>{I, N, eta}, nullptr, "spv.refract");
}
case SPIRV::BI__builtin_spirv_smoothstep: {
Value *Min = EmitScalarExpr(E->getArg(0));
Value *Max = EmitScalarExpr(E->getArg(1));
Value *X = EmitScalarExpr(E->getArg(2));
assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
E->getArg(1)->getType()->hasFloatingRepresentation() &&
E->getArg(2)->getType()->hasFloatingRepresentation() &&
"SmoothStep operands must have a float representation");
return Builder.CreateIntrinsic(
/*ReturnType=*/Min->getType(), Intrinsic::spv_smoothstep,
ArrayRef<Value *>{Min, Max, X}, /*FMFSource=*/nullptr,
"spv.smoothstep");
}
case SPIRV::BI__builtin_spirv_faceforward: {
Value *N = EmitScalarExpr(E->getArg(0));
Value *I = EmitScalarExpr(E->getArg(1));
Value *Ng = EmitScalarExpr(E->getArg(2));
assert(E->getArg(0)->getType()->hasFloatingRepresentation() &&
E->getArg(1)->getType()->hasFloatingRepresentation() &&
E->getArg(2)->getType()->hasFloatingRepresentation() &&
"FaceForward operands must have a float representation");
return Builder.CreateIntrinsic(
/*ReturnType=*/N->getType(), Intrinsic::spv_faceforward,
ArrayRef<Value *>{N, I, Ng}, /*FMFSource=*/nullptr, "spv.faceforward");
}
case SPIRV::BI__builtin_spirv_generic_cast_to_ptr_explicit: {
Value *Ptr = EmitScalarExpr(E->getArg(0));
assert(E->getArg(0)->getType()->hasPointerRepresentation() &&
E->getArg(1)->getType()->hasIntegerRepresentation() &&
"GenericCastToPtrExplicit takes a pointer and an int");
llvm::Type *Res = getTypes().ConvertType(E->getType());
assert(Res->isPointerTy() &&
"GenericCastToPtrExplicit doesn't return a pointer");
llvm::CallInst *Call = Builder.CreateIntrinsic(
/*ReturnType=*/Res, Intrinsic::spv_generic_cast_to_ptr_explicit,
ArrayRef<Value *>{Ptr}, nullptr, "spv.generic_cast");
Call->addRetAttr(llvm::Attribute::AttrKind::NoUndef);
return Call;
}
case SPIRV::BI__builtin_spirv_num_workgroups:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_num_workgroups,
ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
"spv.num.workgroups");
case SPIRV::BI__builtin_spirv_workgroup_size:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_workgroup_size,
ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
"spv.workgroup.size");
case SPIRV::BI__builtin_spirv_workgroup_id:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_group_id,
ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
"spv.group.id");
case SPIRV::BI__builtin_spirv_local_invocation_id:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_thread_id_in_group,
ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
"spv.thread.id.in.group");
case SPIRV::BI__builtin_spirv_global_invocation_id:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_thread_id,
ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
"spv.thread.id");
case SPIRV::BI__builtin_spirv_global_size:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_global_size,
ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
"spv.num.workgroups");
case SPIRV::BI__builtin_spirv_global_offset:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_global_offset,
ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))}, nullptr,
"spv.global.offset");
case SPIRV::BI__builtin_spirv_fwidth:
return Builder.CreateIntrinsic(
/*ReturnType=*/getTypes().ConvertType(E->getType()),
Intrinsic::spv_fwidth, ArrayRef<Value *>{EmitScalarExpr(E->getArg(0))},
nullptr, "spv.fwidth");
}
return nullptr;
}