[HLSL][DXIL][SPIRV] WavePrefixSum intrinsic support

clang/include/clang/Basic/Builtins.td

@@ -5072,6 +5072,12 @@ def HLSLWaveGetLaneCount : LangBuiltin<"HLSL_LANG"> {
   let Prototype = "unsigned int()";
 }
 
+def HLSLWavePrefixSum : LangBuiltin<"HLSL_LANG"> {
+  let Spellings = ["__builtin_hlsl_wave_prefix_sum"];
+  let Attributes = [NoThrow, Const];
+  let Prototype = "void(...)";
+}
+
 def HLSLClamp : LangBuiltin<"HLSL_LANG"> {
   let Spellings = ["__builtin_hlsl_elementwise_clamp"];
   let Attributes = [NoThrow, Const, CustomTypeChecking];

clang/lib/CodeGen/CGHLSLBuiltins.cpp

@@ -295,6 +295,23 @@ static Intrinsic::ID getWaveActiveMinIntrinsic(llvm::Triple::ArchType Arch,
   }
 }
 
+// Return wave prefix sum that corresponds to the QT scalar type
+static Intrinsic::ID getWavePrefixSumIntrinsic(llvm::Triple::ArchType Arch,
+                                               CGHLSLRuntime &RT, QualType QT) {
+  switch (Arch) {
+  case llvm::Triple::spirv:
+    return Intrinsic::spv_wave_prefix_sum;
+  case llvm::Triple::dxil: {
+    if (QT->isUnsignedIntegerType())
+      return Intrinsic::dx_wave_prefix_usum;
+    return Intrinsic::dx_wave_prefix_sum;
+  }
+  default:
+    llvm_unreachable("Intrinsic WavePrefixSum"
+                     " not supported by target architecture");
+  }
+}
+
 // Returns the mangled name for a builtin function that the SPIR-V backend
 // will expand into a spec Constant.
 static std::string getSpecConstantFunctionName(clang::QualType SpecConstantType,
@@ -864,6 +881,15 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
             {OpExpr->getType()}),
         ArrayRef{OpExpr, OpIndex}, "hlsl.wave.readlane");
   }
+  case Builtin::BI__builtin_hlsl_wave_prefix_sum: {
+    Value *OpExpr = EmitScalarExpr(E->getArg(0));
+    Intrinsic::ID IID = getWavePrefixSumIntrinsic(
+        getTarget().getTriple().getArch(), CGM.getHLSLRuntime(),
+        E->getArg(0)->getType());
+    return EmitRuntimeCall(Intrinsic::getOrInsertDeclaration(
+                               &CGM.getModule(), IID, {OpExpr->getType()}),
+                           ArrayRef{OpExpr}, "hlsl.wave.prefix.sum");
+  }
   case Builtin::BI__builtin_hlsl_elementwise_sign: {
     auto *Arg0 = E->getArg(0);
     Value *Op0 = EmitScalarExpr(Arg0);

clang/lib/Headers/hlsl/hlsl_alias_intrinsics.h

@@ -2802,6 +2802,105 @@ __attribute__((convergent)) double3 WaveActiveSum(double3);
 _HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_active_sum)
 __attribute__((convergent)) double4 WaveActiveSum(double4);
 
+//===----------------------------------------------------------------------===//
+// WavePrefixSum builtins
+//===----------------------------------------------------------------------===//
+
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) half WavePrefixSum(half);
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) half2 WavePrefixSum(half2);
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) half3 WavePrefixSum(half3);
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) half4 WavePrefixSum(half4);
+
+#ifdef __HLSL_ENABLE_16_BIT
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int16_t WavePrefixSum(int16_t);
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int16_t2 WavePrefixSum(int16_t2);
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int16_t3 WavePrefixSum(int16_t3);
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int16_t4 WavePrefixSum(int16_t4);
+
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint16_t WavePrefixSum(uint16_t);
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint16_t2 WavePrefixSum(uint16_t2);
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint16_t3 WavePrefixSum(uint16_t3);
+_HLSL_AVAILABILITY(shadermodel, 6.0)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint16_t4 WavePrefixSum(uint16_t4);
+#endif
+
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int WavePrefixSum(int);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int2 WavePrefixSum(int2);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int3 WavePrefixSum(int3);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int4 WavePrefixSum(int4);
+
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint WavePrefixSum(uint);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint2 WavePrefixSum(uint2);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint3 WavePrefixSum(uint3);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint4 WavePrefixSum(uint4);
+
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int64_t WavePrefixSum(int64_t);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int64_t2 WavePrefixSum(int64_t2);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int64_t3 WavePrefixSum(int64_t3);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) int64_t4 WavePrefixSum(int64_t4);
+
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint64_t WavePrefixSum(uint64_t);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint64_t2 WavePrefixSum(uint64_t2);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint64_t3 WavePrefixSum(uint64_t3);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) uint64_t4 WavePrefixSum(uint64_t4);
+
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) float WavePrefixSum(float);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) float2 WavePrefixSum(float2);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) float3 WavePrefixSum(float3);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) float4 WavePrefixSum(float4);
+
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) double WavePrefixSum(double);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) double2 WavePrefixSum(double2);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) double3 WavePrefixSum(double3);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_wave_prefix_sum)
+__attribute__((convergent)) double4 WavePrefixSum(double4);
+
 //===----------------------------------------------------------------------===//
 // sign builtins
 //===----------------------------------------------------------------------===//

clang/lib/Sema/SemaHLSL.cpp

@@ -2892,10 +2892,13 @@ static bool CheckAnyScalarOrVector(Sema *S, CallExpr *TheCall,
   return false;
 }
 
-static bool CheckWaveActive(Sema *S, CallExpr *TheCall) {
+// Check that the argument is not a bool or vector<bool>
+// Returns true on error
+static bool CheckNotBoolScalarOrVector(Sema *S, CallExpr *TheCall,
+                                       unsigned ArgIndex) {
   QualType BoolType = S->getASTContext().BoolTy;
-  assert(TheCall->getNumArgs() >= 1);
-  QualType ArgType = TheCall->getArg(0)->getType();
+  assert(ArgIndex < TheCall->getNumArgs());
+  QualType ArgType = TheCall->getArg(ArgIndex)->getType();
   auto *VTy = ArgType->getAs<VectorType>();
   // is the bool or vector<bool>
   if (S->Context.hasSameUnqualifiedType(ArgType, BoolType) ||
@@ -2909,6 +2912,18 @@ static bool CheckWaveActive(Sema *S, CallExpr *TheCall) {
   return false;
 }
 
+static bool CheckWaveActive(Sema *S, CallExpr *TheCall) {
+  if (CheckNotBoolScalarOrVector(S, TheCall, 0))
+    return true;
+  return false;
+}
+
+static bool CheckWavePrefix(Sema *S, CallExpr *TheCall) {
+  if (CheckNotBoolScalarOrVector(S, TheCall, 0))
+    return true;
+  return false;
+}
+
 static bool CheckBoolSelect(Sema *S, CallExpr *TheCall) {
   assert(TheCall->getNumArgs() == 3);
   Expr *Arg1 = TheCall->getArg(1);
@@ -3371,6 +3386,20 @@ bool SemaHLSL::CheckBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
       return true;
     break;
   }
+  case Builtin::BI__builtin_hlsl_wave_prefix_sum: {
+    if (SemaRef.checkArgCount(TheCall, 1))
+      return true;
+
+    // Ensure input expr type is a scalar/vector and the same as the return type
+    if (CheckAnyScalarOrVector(&SemaRef, TheCall, 0))
+      return true;
+    if (CheckWavePrefix(&SemaRef, TheCall))
+      return true;
+    ExprResult Expr = TheCall->getArg(0);
+    QualType ArgTyExpr = Expr.get()->getType();
+    TheCall->setType(ArgTyExpr);
+    break;
+  }
   case Builtin::BI__builtin_hlsl_elementwise_splitdouble: {
     if (SemaRef.checkArgCount(TheCall, 3))
       return true;

clang/test/CodeGenHLSL/builtins/WavePrefixSum.hlsl

@@ -0,0 +1,46 @@
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
+// RUN:   dxil-pc-shadermodel6.3-compute %s -emit-llvm -disable-llvm-passes -o - | \
+// RUN:   FileCheck %s --check-prefixes=CHECK,CHECK-DXIL
+// RUN: %clang_cc1 -std=hlsl2021 -finclude-default-header -triple \
+// RUN:   spirv-pc-vulkan-compute %s -emit-llvm -disable-llvm-passes -o - | \
+// RUN:   FileCheck %s --check-prefixes=CHECK,CHECK-SPIRV
+
+// Test basic lowering to runtime function call.
+
+// CHECK-LABEL: test_int
+int test_int(int expr) {
+  // CHECK-SPIRV:  %[[RET:.*]] = call spir_func [[TY:.*]] @llvm.spv.wave.prefix.sum.i32([[TY]] %[[#]])
+  // CHECK-DXIL:  %[[RET:.*]] = call [[TY:.*]] @llvm.dx.wave.prefix.sum.i32([[TY]] %[[#]])
+  // CHECK:  ret [[TY]] %[[RET]]
+  return WavePrefixSum(expr);
+}
+
+// CHECK-DXIL: declare [[TY]] @llvm.dx.wave.prefix.sum.i32([[TY]]) #[[#attr:]]
+// CHECK-SPIRV: declare [[TY]] @llvm.spv.wave.prefix.sum.i32([[TY]]) #[[#attr:]]
+
+// CHECK-LABEL: test_uint64_t
+uint64_t test_uint64_t(uint64_t expr) {
+  // CHECK-SPIRV:  %[[RET:.*]] = call spir_func [[TY:.*]] @llvm.spv.wave.prefix.sum.i64([[TY]] %[[#]])
+  // CHECK-DXIL:  %[[RET:.*]] = call [[TY:.*]] @llvm.dx.wave.prefix.usum.i64([[TY]] %[[#]])
+  // CHECK:  ret [[TY]] %[[RET]]
+  return WavePrefixSum(expr);
+}
+
+// CHECK-DXIL: declare [[TY]] @llvm.dx.wave.prefix.usum.i64([[TY]]) #[[#attr:]]
+// CHECK-SPIRV: declare [[TY]] @llvm.spv.wave.prefix.sum.i64([[TY]]) #[[#attr:]]
+
+// Test basic lowering to runtime function call with array and float value.
+
+// CHECK-LABEL: test_floatv4
+float4 test_floatv4(float4 expr) {
+  // CHECK-SPIRV:  %[[RET1:.*]] = call reassoc nnan ninf nsz arcp afn spir_func [[TY1:.*]] @llvm.spv.wave.prefix.sum.v4f32([[TY1]] %[[#]]
+  // CHECK-DXIL:  %[[RET1:.*]] = call reassoc nnan ninf nsz arcp afn [[TY1:.*]] @llvm.dx.wave.prefix.sum.v4f32([[TY1]] %[[#]])
+  // CHECK:  ret [[TY1]] %[[RET1]]
+  return WavePrefixSum(expr);
+}
+
+// CHECK-DXIL: declare [[TY1]] @llvm.dx.wave.prefix.sum.v4f32([[TY1]]) #[[#attr]]
+// CHECK-SPIRV: declare [[TY1]] @llvm.spv.wave.prefix.sum.v4f32([[TY1]]) #[[#attr]]
+
+// CHECK: attributes #[[#attr]] = {{{.*}} convergent {{.*}}}
+

clang/test/SemaHLSL/BuiltIns/WavePrefixSum-errors.hlsl

@@ -0,0 +1,28 @@
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.6-library %s -emit-llvm-only -disable-llvm-passes -verify
+
+int test_too_few_arg() {
+  return __builtin_hlsl_wave_prefix_sum();
+  // expected-error@-1 {{too few arguments to function call, expected 1, have 0}}
+}
+
+float2 test_too_many_arg(float2 p0) {
+  return __builtin_hlsl_wave_prefix_sum(p0, p0);
+  // expected-error@-1 {{too many arguments to function call, expected 1, have 2}}
+}
+
+bool test_expr_bool_type_check(bool p0) {
+  return __builtin_hlsl_wave_prefix_sum(p0);
+  // expected-error@-1 {{invalid operand of type 'bool'}}
+}
+
+bool2 test_expr_bool_vec_type_check(bool2 p0) {
+  return __builtin_hlsl_wave_prefix_sum(p0);
+  // expected-error@-1 {{invalid operand of type 'bool2' (aka 'vector<bool, 2>')}}
+}
+
+struct S { float f; };
+
+S test_expr_struct_type_check(S p0) {
+  return __builtin_hlsl_wave_prefix_sum(p0);
+  // expected-error@-1 {{invalid operand of type 'S' where a scalar or vector is required}}
+}

llvm/include/llvm/IR/IntrinsicsDirectX.td

@@ -164,6 +164,8 @@ def int_dx_wave_is_first_lane : DefaultAttrsIntrinsic<[llvm_i1_ty], [], [IntrCon
 def int_dx_wave_readlane : DefaultAttrsIntrinsic<[llvm_any_ty], [LLVMMatchType<0>, llvm_i32_ty], [IntrConvergent, IntrNoMem]>;
 def int_dx_wave_get_lane_count
     : DefaultAttrsIntrinsic<[llvm_i32_ty], [], [IntrConvergent]>;
+def int_dx_wave_prefix_sum : DefaultAttrsIntrinsic<[llvm_any_ty], [LLVMMatchType<0>], [IntrConvergent, IntrNoMem]>;
+def int_dx_wave_prefix_usum : DefaultAttrsIntrinsic<[llvm_anyint_ty], [LLVMMatchType<0>], [IntrConvergent, IntrNoMem]>;
 def int_dx_sign : DefaultAttrsIntrinsic<[LLVMScalarOrSameVectorWidth<0, llvm_i32_ty>], [llvm_any_ty], [IntrNoMem]>;
 def int_dx_step : DefaultAttrsIntrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty, LLVMMatchType<0>], [IntrNoMem]>;
 def int_dx_splitdouble : DefaultAttrsIntrinsic<[llvm_anyint_ty, LLVMMatchType<0>],

llvm/include/llvm/IR/IntrinsicsSPIRV.td

@@ -129,6 +129,7 @@ def int_spv_rsqrt : DefaultAttrsIntrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty]
   def int_spv_wave_readlane : DefaultAttrsIntrinsic<[llvm_any_ty], [LLVMMatchType<0>, llvm_i32_ty], [IntrConvergent, IntrNoMem]>;
   def int_spv_wave_get_lane_count
       : DefaultAttrsIntrinsic<[llvm_i32_ty], [], [IntrConvergent]>;
+  def int_spv_wave_prefix_sum : DefaultAttrsIntrinsic<[llvm_any_ty], [LLVMMatchType<0>], [IntrConvergent, IntrNoMem]>;
   def int_spv_sign : DefaultAttrsIntrinsic<[LLVMScalarOrSameVectorWidth<0, llvm_i32_ty>], [llvm_any_ty], [IntrNoMem]>;
   def int_spv_radians : DefaultAttrsIntrinsic<[LLVMMatchType<0>], [llvm_anyfloat_ty], [IntrNoMem]>;
   def int_spv_group_memory_barrier_with_group_sync

llvm/lib/Target/DirectX/DXIL.td

@@ -1079,6 +1079,30 @@ def WaveActiveOp : DXILOp<119, waveActiveOp> {
   let attributes = [Attributes<DXIL1_0, []>];
 }
 
+def WavePrefixOp : DXILOp<121, wavePrefixOp> {
+  let Doc = "returns partial result of the computation in the corresponding lane";
+  let intrinsics = [
+    IntrinSelect<int_dx_wave_prefix_sum,
+                 [
+                   IntrinArgIndex<0>, IntrinArgI8<WaveOpKind_Sum>,
+                   IntrinArgI8<SignedOpKind_Signed>
+                 ]>,
+    IntrinSelect<int_dx_wave_prefix_usum,
+                 [
+                   IntrinArgIndex<0>, IntrinArgI8<WaveOpKind_Sum>,
+                   IntrinArgI8<SignedOpKind_Unsigned>
+                 ]>,
+  ];
+
+  let arguments = [OverloadTy, Int8Ty, Int8Ty];
+  let result = OverloadTy;
+  let overloads = [
+    Overloads<DXIL1_0, [HalfTy, FloatTy, DoubleTy, Int16Ty, Int32Ty, Int64Ty]>
+  ];
+  let stages = [Stages<DXIL1_0, [all_stages]>];
+  let attributes = [Attributes<DXIL1_0, []>];
+}
+
 def LegacyF16ToF32 : DXILOp<131, legacyF16ToF32> {
   let Doc = "returns the float16 stored in the low-half of the uint converted "
             "to a float";

llvm/lib/Target/DirectX/DXILShaderFlags.cpp

@@ -96,6 +96,8 @@ static bool checkWaveOps(Intrinsic::ID IID) {
   case Intrinsic::dx_wave_reduce_umax:
   case Intrinsic::dx_wave_reduce_min:
   case Intrinsic::dx_wave_reduce_umin:
+    // Wave Prefix Op Variants
+  case Intrinsic::dx_wave_prefix_sum:
     return true;
   }
 }

llvm/lib/Target/DirectX/DirectXTargetTransformInfo.cpp

@@ -59,9 +59,11 @@ bool DirectXTTIImpl::isTargetIntrinsicTriviallyScalarizable(
   case Intrinsic::dx_wave_reduce_max:
   case Intrinsic::dx_wave_reduce_min:
   case Intrinsic::dx_wave_reduce_sum:
+  case Intrinsic::dx_wave_prefix_sum:
   case Intrinsic::dx_wave_reduce_umax:
   case Intrinsic::dx_wave_reduce_umin:
   case Intrinsic::dx_wave_reduce_usum:
+  case Intrinsic::dx_wave_prefix_usum:
   case Intrinsic::dx_imad:
   case Intrinsic::dx_umad:
     return true;