[HLSL] implement the isinf intrinsic (#84927)

This change implements part 1 of 2 for #70095 - `hlsl_intrinsics.h` - add the `isinf` api - `Builtins.td` - add an hlsl builtin for `isinf`. - `CGBuiltin.cpp` add the ir generation for `isinf` intrinsic. - `SemaChecking.cpp` - add a non-math elementwise checks because this is a bool return. - `IntrinsicsDirectX.td` - add an `isinf` intrinsic. `DXIL.td` lowering is left, but changes need to be made there before we can support this case.
llvm · Mar 14, 2024 · d192b64 · d192b64
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diff --git a/clang/include/clang/Basic/Builtins.td b/clang/include/clang/Basic/Builtins.td
@@ -4572,6 +4572,12 @@ def HLSLFrac : LangBuiltin<"HLSL_LANG"> {
   let Prototype = "void(...)";
 }
 
+def HLSLIsinf : LangBuiltin<"HLSL_LANG"> {
+  let Spellings = ["__builtin_hlsl_elementwise_isinf"];
+  let Attributes = [NoThrow, Const];
+  let Prototype = "void(...)";
+}
+
 def HLSLLerp : LangBuiltin<"HLSL_LANG"> {
   let Spellings = ["__builtin_hlsl_lerp"];
   let Attributes = [NoThrow, Const];

diff --git a/clang/lib/CodeGen/CGBuiltin.cpp b/clang/lib/CodeGen/CGBuiltin.cpp
@@ -18062,6 +18062,20 @@ Value *CodeGenFunction::EmitHLSLBuiltinExpr(unsigned BuiltinID,
         /*ReturnType=*/Op0->getType(), Intrinsic::dx_frac,
         ArrayRef<Value *>{Op0}, nullptr, "dx.frac");
   }
+  case Builtin::BI__builtin_hlsl_elementwise_isinf: {
+    Value *Op0 = EmitScalarExpr(E->getArg(0));
+    llvm::Type *Xty = Op0->getType();
+    llvm::Type *retType = llvm::Type::getInt1Ty(this->getLLVMContext());
+    if (Xty->isVectorTy()) {
+      auto *XVecTy = E->getArg(0)->getType()->getAs<VectorType>();
+      retType = llvm::VectorType::get(
+          retType, ElementCount::getFixed(XVecTy->getNumElements()));
+    }
+    if (!E->getArg(0)->getType()->hasFloatingRepresentation())
+      llvm_unreachable("isinf operand must have a float representation");
+    return Builder.CreateIntrinsic(retType, Intrinsic::dx_isinf,
+                                   ArrayRef<Value *>{Op0}, nullptr, "dx.isinf");
+  }
   case Builtin::BI__builtin_hlsl_mad: {
     Value *M = EmitScalarExpr(E->getArg(0));
     Value *A = EmitScalarExpr(E->getArg(1));

diff --git a/clang/lib/Headers/hlsl/hlsl_intrinsics.h b/clang/lib/Headers/hlsl/hlsl_intrinsics.h
@@ -525,6 +525,39 @@ float3 frac(float3);
 _HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_frac)
 float4 frac(float4);
 
+//===----------------------------------------------------------------------===//
+// isinf builtins
+//===----------------------------------------------------------------------===//
+
+/// \fn T isinf(T x)
+/// \brief Determines if the specified value \a x  is infinite.
+/// \param x The specified input value.
+///
+/// Returns a value of the same size as the input, with a value set
+/// to True if the x parameter is +INF or -INF. Otherwise, False.
+
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool isinf(half);
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool2 isinf(half2);
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool3 isinf(half3);
+_HLSL_16BIT_AVAILABILITY(shadermodel, 6.2)
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool4 isinf(half4);
+
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool isinf(float);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool2 isinf(float2);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool3 isinf(float3);
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_elementwise_isinf)
+bool4 isinf(float4);
+
 //===----------------------------------------------------------------------===//
 // lerp builtins
 //===----------------------------------------------------------------------===//

diff --git a/clang/lib/Sema/SemaChecking.cpp b/clang/lib/Sema/SemaChecking.cpp
@@ -5268,6 +5268,15 @@ bool CheckAllArgsHaveFloatRepresentation(Sema *S, CallExpr *TheCall) {
   return false;
 }
 
+void SetElementTypeAsReturnType(Sema *S, CallExpr *TheCall,
+                                QualType ReturnType) {
+  auto *VecTyA = TheCall->getArg(0)->getType()->getAs<VectorType>();
+  if (VecTyA)
+    ReturnType = S->Context.getVectorType(ReturnType, VecTyA->getNumElements(),
+                                          VectorKind::Generic);
+  TheCall->setType(ReturnType);
+}
+
 // Note: returning true in this case results in CheckBuiltinFunctionCall
 // returning an ExprError
 bool Sema::CheckHLSLBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
@@ -5286,6 +5295,14 @@ bool Sema::CheckHLSLBuiltinFunctionCall(unsigned BuiltinID, CallExpr *TheCall) {
       return true;
     break;
   }
+  case Builtin::BI__builtin_hlsl_elementwise_isinf: {
+    if (checkArgCount(*this, TheCall, 1))
+      return true;
+    if (CheckAllArgsHaveFloatRepresentation(this, TheCall))
+      return true;
+    SetElementTypeAsReturnType(this, TheCall, this->Context.BoolTy);
+    break;
+  }
   case Builtin::BI__builtin_hlsl_elementwise_rsqrt:
   case Builtin::BI__builtin_hlsl_elementwise_rcp:
   case Builtin::BI__builtin_hlsl_elementwise_frac: {

diff --git a/clang/test/CodeGenHLSL/builtins/isinf.hlsl b/clang/test/CodeGenHLSL/builtins/isinf.hlsl
@@ -0,0 +1,45 @@
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s -fnative-half-type \
+// RUN:   -emit-llvm -disable-llvm-passes -o - | FileCheck %s \ 
+// RUN:   --check-prefixes=CHECK,NATIVE_HALF
+// RUN: %clang_cc1 -finclude-default-header -x hlsl -triple \
+// RUN:   dxil-pc-shadermodel6.3-library %s -emit-llvm -disable-llvm-passes \
+// RUN:   -o - | FileCheck %s --check-prefixes=CHECK,NO_HALF
+
+// CHECK: define noundef i1 @
+// NATIVE_HALF: %dx.isinf = call i1 @llvm.dx.isinf.f16(
+// NO_HALF: %dx.isinf = call i1 @llvm.dx.isinf.f32(
+// CHECK: ret i1 %dx.isinf
+bool test_isinf_half(half p0) { return isinf(p0); }
+// CHECK: define noundef <2 x i1> @
+// NATIVE_HALF: %dx.isinf = call <2 x i1> @llvm.dx.isinf.v2f16
+// NO_HALF: %dx.isinf = call <2 x i1> @llvm.dx.isinf.v2f32(
+// CHECK: ret <2 x i1> %dx.isinf
+bool2 test_isinf_half2(half2 p0) { return isinf(p0); }
+// NATIVE_HALF: define noundef <3 x i1> @
+// NATIVE_HALF: %dx.isinf = call <3 x i1> @llvm.dx.isinf.v3f16
+// NO_HALF: %dx.isinf = call <3 x i1> @llvm.dx.isinf.v3f32(
+// CHECK: ret <3 x i1> %dx.isinf
+bool3 test_isinf_half3(half3 p0) { return isinf(p0); }
+// NATIVE_HALF: define noundef <4 x i1> @
+// NATIVE_HALF: %dx.isinf = call <4 x i1> @llvm.dx.isinf.v4f16
+// NO_HALF: %dx.isinf = call <4 x i1> @llvm.dx.isinf.v4f32(
+// CHECK: ret <4 x i1> %dx.isinf
+bool4 test_isinf_half4(half4 p0) { return isinf(p0); }
+
+// CHECK: define noundef i1 @
+// CHECK: %dx.isinf = call i1 @llvm.dx.isinf.f32(
+// CHECK: ret i1 %dx.isinf
+bool test_isinf_float(float p0) { return isinf(p0); }
+// CHECK: define noundef <2 x i1> @
+// CHECK: %dx.isinf = call <2 x i1> @llvm.dx.isinf.v2f32
+// CHECK: ret <2 x i1> %dx.isinf
+bool2 test_isinf_float2(float2 p0) { return isinf(p0); }
+// CHECK: define noundef <3 x i1> @
+// CHECK: %dx.isinf = call <3 x i1> @llvm.dx.isinf.v3f32
+// CHECK: ret <3 x i1> %dx.isinf
+bool3 test_isinf_float3(float3 p0) { return isinf(p0); }
+// CHECK: define noundef <4 x i1> @
+// CHECK: %dx.isinf = call <4 x i1> @llvm.dx.isinf.v4f32
+// CHECK: ret <4 x i1> %dx.isinf
+bool4 test_isinf_float4(float4 p0) { return isinf(p0); }
diff --git a/clang/test/SemaHLSL/BuiltIns/isinf-errors.hlsl b/clang/test/SemaHLSL/BuiltIns/isinf-errors.hlsl
@@ -0,0 +1,27 @@
+
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.6-library %s -fnative-half-type -emit-llvm -disable-llvm-passes -verify -verify-ignore-unexpected
+
+bool test_too_few_arg() {
+  return __builtin_hlsl_elementwise_isinf();
+  // expected-error@-1 {{too few arguments to function call, expected 1, have 0}}
+}
+
+bool2 test_too_many_arg(float2 p0) {
+  return __builtin_hlsl_elementwise_isinf(p0, p0);
+  // expected-error@-1 {{too many arguments to function call, expected 1, have 2}}
+}
+
+bool builtin_bool_to_float_type_promotion(bool p1) {
+  return __builtin_hlsl_elementwise_isinf(p1);
+  // expected-error@-1 {passing 'bool' to parameter of incompatible type 'float'}}
+}
+
+bool builtin_isinf_int_to_float_promotion(int p1) {
+  return __builtin_hlsl_elementwise_isinf(p1);
+  // expected-error@-1 {{passing 'int' to parameter of incompatible type 'float'}}
+}
+
+bool2 builtin_isinf_int2_to_float2_promotion(int2 p1) {
+  return __builtin_hlsl_elementwise_isinf(p1);
+  // expected-error@-1 {{passing 'int2' (aka 'vector<int, 2>') to parameter of incompatible type '__attribute__((__vector_size__(2 * sizeof(float)))) float' (vector of 2 'float' values)}}
+}
diff --git a/llvm/include/llvm/IR/IntrinsicsDirectX.td b/llvm/include/llvm/IR/IntrinsicsDirectX.td
@@ -29,6 +29,10 @@ def int_dx_dot :
 
 def int_dx_frac  : DefaultAttrsIntrinsic<[llvm_anyfloat_ty], [LLVMMatchType<0>]>;
 
+def int_dx_isinf :
+    DefaultAttrsIntrinsic<[LLVMScalarOrSameVectorWidth<0, llvm_i1_ty>],
+    [llvm_anyfloat_ty]>;
+
 def int_dx_lerp :
     Intrinsic<[LLVMScalarOrSameVectorWidth<0, LLVMVectorElementType<0>>],
     [llvm_anyvector_ty, LLVMScalarOrSameVectorWidth<0, LLVMVectorElementType<0>>,LLVMScalarOrSameVectorWidth<0, LLVMVectorElementType<0>>],