[HLSL] select scalar overloads for vector conditions

This PR adds scalar/vector overloads for vector conditions to the
`select` builtin, and updates the sema checking and codegen to allow
scalars to extend to vectors.

Fixes #126570

Author: llvm-beanz

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -12682,6 +12682,9 @@ def err_hlsl_param_qualifier_mismatch :
 def err_hlsl_vector_compound_assignment_truncation : Error<
   "left hand operand of type %0 to compound assignment cannot be truncated "
   "when used with right hand operand of type %1">;
+def err_hlsl_builtin_scalar_vector_mismatch : Error<
+  "%select{all|second and third}0 arguments to %1 must be of scalar or "
+  "vector type with matching scalar element type%diff{: $ vs $|}2,3">;
 
 def warn_hlsl_impcast_vector_truncation : Warning<
   "implicit conversion truncates vector: %0 to %1">, InGroup<Conversion>;

clang/lib/CodeGen/CGBuiltin.cpp

@@ -19741,6 +19741,14 @@ case Builtin::BI__builtin_hlsl_elementwise_isinf: {
         RValFalse.isScalar()
             ? RValFalse.getScalarVal()
             : RValFalse.getAggregatePointer(E->getArg(2)->getType(), *this);
+    if (auto *VTy = E->getType()->getAs<VectorType>()) {
+      if (!OpTrue->getType()->isVectorTy())
+        OpTrue =
+            Builder.CreateVectorSplat(VTy->getNumElements(), OpTrue, "splat");
+      if (!OpFalse->getType()->isVectorTy())
+        OpFalse =
+            Builder.CreateVectorSplat(VTy->getNumElements(), OpFalse, "splat");
+    }
 
     Value *SelectVal =
         Builder.CreateSelect(OpCond, OpTrue, OpFalse, "hlsl.select");

clang/lib/Headers/hlsl/hlsl_detail.h

@@ -95,6 +95,11 @@ constexpr vector<T, L> reflect_vec_impl(vector<T, L> I, vector<T, L> N) {
 #endif
 }
 
+template<typename T>
+struct is_arithmetic {
+  static const bool Value = __is_arithmetic(T);
+};
+
 } // namespace __detail
 } // namespace hlsl
 #endif //_HLSL_HLSL_DETAILS_H_

clang/lib/Headers/hlsl/hlsl_intrinsics.h

@@ -2246,6 +2246,42 @@ template <typename T, int Sz>
 _HLSL_BUILTIN_ALIAS(__builtin_hlsl_select)
 vector<T, Sz> select(vector<bool, Sz>, vector<T, Sz>, vector<T, Sz>);
 
+
+/// \fn vector<T,Sz> select(vector<bool,Sz> Conds, T TrueVal,
+///                         vector<T,Sz> FalseVals)
+/// \brief ternary operator for vectors. All vectors must be the same size.
+/// \param Conds The Condition input values.
+/// \param TrueVal The scalar value to splat from when conditions are true.
+/// \param FalseVals The vector values are chosen from when conditions are
+/// false.
+
+template <typename T, int Sz>
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_select)
+vector<T, Sz> select(vector<bool, Sz>, T, vector<T, Sz>);
+
+/// \fn vector<T,Sz> select(vector<bool,Sz> Conds, vector<T,Sz> TrueVals,
+///                         T FalseVal)
+/// \brief ternary operator for vectors. All vectors must be the same size.
+/// \param Conds The Condition input values.
+/// \param TrueVals The vector values are chosen from when conditions are true.
+/// \param FalseVal The scalar value to splat from when conditions are false.
+
+template <typename T, int Sz>
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_select)
+vector<T, Sz> select(vector<bool, Sz>, vector<T, Sz>, T);
+
+/// \fn vector<T,Sz> select(vector<bool,Sz> Conds, vector<T,Sz> TrueVals,
+///                         T FalseVal)
+/// \brief ternary operator for vectors. All vectors must be the same size.
+/// \param Conds The Condition input values.
+/// \param TrueVal The scalar value to splat from when conditions are true.
+/// \param FalseVal The scalar value to splat from when conditions are false.
+
+template <typename T, int Sz>
+_HLSL_BUILTIN_ALIAS(__builtin_hlsl_select)
+__detail::enable_if_t<__detail::is_arithmetic<T>::Value, vector<T, Sz>> select(
+    vector<bool, Sz>, T, T);
+
 //===----------------------------------------------------------------------===//
 // sin builtins
 //===----------------------------------------------------------------------===//

clang/lib/Sema/SemaHLSL.cpp

@@ -2213,40 +2213,48 @@ static bool CheckBoolSelect(Sema *S, CallExpr *TheCall) {
 static bool CheckVectorSelect(Sema *S, CallExpr *TheCall) {
   assert(TheCall->getNumArgs() == 3);
   Expr *Arg1 = TheCall->getArg(1);
+  QualType Arg1Ty = Arg1->getType();
   Expr *Arg2 = TheCall->getArg(2);
-  if (!Arg1->getType()->isVectorType()) {
-    S->Diag(Arg1->getBeginLoc(), diag::err_builtin_non_vector_type)
-        << "Second" << TheCall->getDirectCallee() << Arg1->getType()
+  QualType Arg2Ty = Arg2->getType();
+
+  QualType Arg1ScalarTy = Arg1Ty;
+  if (auto VTy = Arg1ScalarTy->getAs<VectorType>())
+    Arg1ScalarTy = VTy->getElementType();
+
+  QualType Arg2ScalarTy = Arg2Ty;
+  if (auto VTy = Arg2ScalarTy->getAs<VectorType>())
+    Arg2ScalarTy = VTy->getElementType();
+
+  if (!S->Context.hasSameUnqualifiedType(Arg1ScalarTy, Arg2ScalarTy))
+    S->Diag(Arg1->getBeginLoc(), diag::err_hlsl_builtin_scalar_vector_mismatch)
+        << /* second and third */ 1 << TheCall->getCallee() << Arg1Ty << Arg2Ty;
+
+  QualType Arg0Ty = TheCall->getArg(0)->getType();
+  unsigned Arg0Length = Arg0Ty->getAs<VectorType>()->getNumElements();
+  unsigned Arg1Length = Arg1Ty->isVectorType()
+                            ? Arg1Ty->getAs<VectorType>()->getNumElements()
+                            : 0;
+  unsigned Arg2Length = Arg2Ty->isVectorType()
+                            ? Arg2Ty->getAs<VectorType>()->getNumElements()
+                            : 0;
+  if (Arg1Length > 0 && Arg0Length != Arg1Length) {
+    S->Diag(TheCall->getBeginLoc(),
+            diag::err_typecheck_vector_lengths_not_equal)
+        << Arg0Ty << Arg1Ty << TheCall->getArg(0)->getSourceRange()
         << Arg1->getSourceRange();
     return true;
   }
 
-  if (!Arg2->getType()->isVectorType()) {
-    S->Diag(Arg2->getBeginLoc(), diag::err_builtin_non_vector_type)
-        << "Third" << TheCall->getDirectCallee() << Arg2->getType()
-        << Arg2->getSourceRange();
-    return true;
-  }
-
-  if (!S->Context.hasSameUnqualifiedType(Arg1->getType(), Arg2->getType())) {
+  if (Arg2Length > 0 && Arg0Length != Arg2Length) {
     S->Diag(TheCall->getBeginLoc(),
-            diag::err_typecheck_call_different_arg_types)
-        << Arg1->getType() << Arg2->getType() << Arg1->getSourceRange()
+            diag::err_typecheck_vector_lengths_not_equal)
+        << Arg0Ty << Arg2Ty << TheCall->getArg(0)->getSourceRange()
         << Arg2->getSourceRange();
     return true;
   }
 
-  // caller has checked that Arg0 is a vector.
-  // check all three args have the same length.
-  if (TheCall->getArg(0)->getType()->getAs<VectorType>()->getNumElements() !=
-      Arg1->getType()->getAs<VectorType>()->getNumElements()) {
-    S->Diag(TheCall->getBeginLoc(),
-            diag::err_typecheck_vector_lengths_not_equal)
-        << TheCall->getArg(0)->getType() << Arg1->getType()
-        << TheCall->getArg(0)->getSourceRange() << Arg1->getSourceRange();
-    return true;
-  }
-  TheCall->setType(Arg1->getType());
+  TheCall->setType(
+      S->getASTContext().getExtVectorType(Arg1ScalarTy, Arg0Length));
   return false;
 }
 

clang/test/CodeGenHLSL/builtins/select.hlsl

@@ -52,3 +52,32 @@ int3 test_select_vector_3(bool3 cond0, int3 tVals, int3 fVals) {
 int4 test_select_vector_4(bool4 cond0, int4 tVals, int4 fVals) {
   return select(cond0, tVals, fVals);
 }
+
+// CHECK-LABEL: test_select_vector_scalar_vector
+// CHECK: [[SPLAT_SRC1:%.*]] = insertelement <4 x i32> poison, i32 {{%.*}}, i64 0
+// CHECK: [[SPLAT1:%.*]] = shufflevector <4 x i32> [[SPLAT_SRC1]], <4 x i32> poison, <4 x i32> zeroinitializer
+// CHECK: [[SELECT:%.*]] = select <4 x i1> {{%.*}}, <4 x i32> [[SPLAT1]], <4 x i32> {{%.*}}
+// CHECK: ret <4 x i32> [[SELECT]]
+int4 test_select_vector_scalar_vector(bool4 cond0, int tVal, int4 fVals) {
+  return select(cond0, tVal, fVals);
+}
+
+// CHECK-LABEL: test_select_vector_vector_scalar
+// CHECK: [[SPLAT_SRC1:%.*]] = insertelement <4 x i32> poison, i32 {{%.*}}, i64 0
+// CHECK: [[SPLAT1:%.*]] = shufflevector <4 x i32> [[SPLAT_SRC1]], <4 x i32> poison, <4 x i32> zeroinitializer
+// CHECK: [[SELECT:%.*]] = select <4 x i1> {{%.*}}, <4 x i32> {{%.*}}, <4 x i32> [[SPLAT1]]
+// CHECK: ret <4 x i32> [[SELECT]]
+int4 test_select_vector_vector_scalar(bool4 cond0, int4 tVals, int fVal) {
+  return select(cond0, tVals, fVal);
+}
+
+// CHECK-LABEL: test_select_vector_scalar_scalar
+// CHECK: [[SPLAT_SRC1:%.*]] = insertelement <4 x i32> poison, i32 {{%.*}}, i64 0
+// CHECK: [[SPLAT1:%.*]] = shufflevector <4 x i32> [[SPLAT_SRC1]], <4 x i32> poison, <4 x i32> zeroinitializer
+// CHECK: [[SPLAT_SRC2:%.*]] = insertelement <4 x i32> poison, i32 %3, i64 0
+// CHECK: [[SPLAT2:%.*]] = shufflevector <4 x i32> [[SPLAT_SRC2]], <4 x i32> poison, <4 x i32> zeroinitializer
+// CHECK: [[SELECT:%.*]] = select <4 x i1> {{%.*}}, <4 x i32> [[SPLAT1]], <4 x i32> [[SPLAT2]]
+// CHECK: ret <4 x i32> [[SELECT]]
+int4 test_select_vector_scalar_scalar(bool4 cond0, int tVal, int fVal) {
+  return select(cond0, tVal, fVal);
+}

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

@@ -1,119 +1,65 @@
-// RUN: %clang_cc1 -finclude-default-header
-// -triple dxil-pc-shadermodel6.6-library %s -emit-llvm-only
-// -disable-llvm-passes -verify -verify-ignore-unexpected
+// RUN: %clang_cc1 -finclude-default-header -triple dxil-pc-shadermodel6.6-library %s -emit-llvm-only -disable-llvm-passes -verify
 
-int test_no_arg() {
-  return select();
-  // expected-error@-1 {{no matching function for call to 'select'}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template
-  // not viable: requires 3 arguments, but 0 were provided}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not
-  // viable: requires 3 arguments, but 0 were provided}}
-}
-
-int test_too_few_args(bool p0) {
-  return select(p0);
-  // expected-error@-1 {{no matching function for call to 'select'}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not
-  // viable: requires 3 arguments, but 1 was provided}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not
-  // viable: requires 3 arguments, but 1 was provided}}
-}
-
-int test_too_many_args(bool p0, int t0, int f0, int g0) {
-  return select<int>(p0, t0, f0, g0);
-  // expected-error@-1 {{no matching function for call to 'select'}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not
-  // viable: requires 3 arguments, but 4 were provided}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not
-  // viable: requires 3 arguments, but 4 were provided}}
-}
 
 int test_select_first_arg_wrong_type(int1 p0, int t0, int f0) {
   return select(p0, t0, f0);
-  // expected-error@-1 {{no matching function for call to 'select'}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not
-  // viable: no known conversion from 'vector<int, 1>' (vector of 1 'int' value)
-  // to 'bool' for 1st argument}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored: could
-  // not match 'vector<T, Sz>' against 'int'}}
 }
 
 int1 test_select_bool_vals_diff_vecs(bool p0, int1 t0, int1 f0) {
   return select<int1>(p0, t0, f0);
-  // expected-warning@-1 {{implicit conversion truncates vector:
-  // 'vector<int, 2>' (vector of 2 'int' values) to 'vector<int, 1>'
-  // (vector of 1 'int' value)}}
 }
 
 int2 test_select_vector_vals_not_vecs(bool2 p0, int t0,
                                                int f0) {
   return select(p0, t0, f0);
-  // expected-error@-1 {{no matching function for call to 'select'}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate template ignored:
-  // could not match 'vector<T, Sz>' against 'int'}}
-  // expected-note@hlsl/hlsl_intrinsics.h:* {{candidate function template not
-  // viable: no known conversion from 'vector<bool, 2>'
-  // (vector of 2 'bool' values) to 'bool' for 1st argument}}
 }
 
 int1 test_select_vector_vals_wrong_size(bool2 p0, int1 t0, int1 f0) {
-  return select<int,1>(p0, t0, f0); // produce warnings
-  // expected-warning@-1 {{implicit conversion truncates vector:
-  // 'vector<bool, 2>' (vector of 2 'bool' values) to 'vector<bool, 1>'
-  // (vector of 1 'bool' value)}}
-  // expected-warning@-2 {{implicit conversion truncates vector:
-  // 'vector<int, 2>' (vector of 2 'int' values) to 'vector<int, 1>'
-  // (vector of 1 'int' value)}}
+  return select<int,1>(p0, t0, f0); // expected-warning{{implicit conversion truncates vector: 'bool2' (aka 'vector<bool, 2>') to 'vector<bool, 1>' (vector of 1 'bool' value)}}
+}
+
+int test_select_no_args() {
+  return __builtin_hlsl_select(); // expected-error{{too few arguments to function call, expected 3, have 0}}
+}
+
+int test_select_builtin_wrong_arg_count(bool p0) {
+  return __builtin_hlsl_select(p0); // expected-error{{too few arguments to function call, expected 3, have 1}}
 }
 
 // __builtin_hlsl_select tests
-int test_select_builtin_wrong_arg_count(bool p0, int t0) {
-  return __builtin_hlsl_select(p0, t0);
-  // expected-error@-1 {{too few arguments to function call, expected 3,
-  // have 2}}
+int test_select_builtin_wrong_arg_count2(bool p0, int t0) {
+  return __builtin_hlsl_select(p0, t0); // expected-error{{too few arguments to function call, expected 3, have 2}}
+}
+
+int test_too_many_args(bool p0, int t0, int f0, int g0) {
+  return __builtin_hlsl_select(p0, t0, f0, g0); // expected-error{{too many arguments to function call, expected 3, have 4}}
 }
 
 // not a bool or a vector of bool. should be 2 errors.
 int test_select_builtin_first_arg_wrong_type1(int p0, int t0, int f0) {
-  return __builtin_hlsl_select(p0, t0, f0);
-  // expected-error@-1 {{passing 'int' to parameter of incompatible type
-  // 'bool'}}
-  // expected-error@-2 {{First argument to __builtin_hlsl_select must be of
-  // vector type}}
-  }
+  return __builtin_hlsl_select(p0, t0, f0); // expected-error{{invalid operand of type 'int' where 'bool' or a vector of such type is required}}
+}
 
 int test_select_builtin_first_arg_wrong_type2(int1 p0, int t0, int f0) {
-  return __builtin_hlsl_select(p0, t0, f0);
-  // expected-error@-1 {{passing 'vector<int, 1>' (vector of 1 'int' value) to
-  // parameter of incompatible type 'bool'}}
-  // expected-error@-2 {{First argument to __builtin_hlsl_select must be of
-  // vector type}}
+  return __builtin_hlsl_select(p0, t0, f0); // expected-error{{invalid operand of type 'int1' (aka 'vector<int, 1>') where 'bool' or a vector of such type is required}}
 }
 
 // if a bool last 2 args are of same type
 int test_select_builtin_bool_incompatible_args(bool p0, int t0, double f0) {
-  return __builtin_hlsl_select(p0, t0, f0);
-  // expected-error@-1 {{arguments are of different types ('int' vs 'double')}}
+  return __builtin_hlsl_select(p0, t0, f0); // expected-error{{arguments are of different types ('int' vs 'double')}}
 }
 
 // if a vector second arg isnt a vector
 int2 test_select_builtin_second_arg_not_vector(bool2 p0, int t0, int2 f0) {
   return __builtin_hlsl_select(p0, t0, f0);
-  // expected-error@-1 {{Second argument to __builtin_hlsl_select must be of
-  // vector type}}
 }
 
 // if a vector third arg isn't a vector
 int2 test_select_builtin_second_arg_not_vector(bool2 p0, int2 t0, int f0) {
   return __builtin_hlsl_select(p0, t0, f0);
-  // expected-error@-1 {{Third argument to __builtin_hlsl_select must be of
-  // vector type}}
 }
 
 // if vector last 2 aren't same type (so both are vectors but wrong type)
-int2 test_select_builtin_diff_types(bool1 p0, int1 t0, float1 f0) {
-  return __builtin_hlsl_select(p0, t0, f0);
-  // expected-error@-1 {{arguments are of different types ('vector<int, [...]>'
-  // vs 'vector<float, [...]>')}}
+int1 test_select_builtin_diff_types(bool1 p0, int1 t0, float1 f0) {
+  return __builtin_hlsl_select(p0, t0, f0); // expected-error{{second and third arguments to __builtin_hlsl_select must be of scalar or vector type with matching scalar element type: 'vector<int, [...]>' vs 'vector<float, [...]>'}}
 }