1 //===-- lib/Evaluate/fold-complex.cpp -------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "fold-implementation.h"
10 
11 namespace Fortran::evaluate {
12 
13 template <int KIND>
14 Expr<Type<TypeCategory::Complex, KIND>> FoldIntrinsicFunction(
15     FoldingContext &context,
16     FunctionRef<Type<TypeCategory::Complex, KIND>> &&funcRef) {
17   using T = Type<TypeCategory::Complex, KIND>;
18   ActualArguments &args{funcRef.arguments()};
19   auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)};
20   CHECK(intrinsic);
21   std::string name{intrinsic->name};
22   if (name == "acos" || name == "acosh" || name == "asin" || name == "asinh" ||
23       name == "atan" || name == "atanh" || name == "cos" || name == "cosh" ||
24       name == "exp" || name == "log" || name == "sin" || name == "sinh" ||
25       name == "sqrt" || name == "tan" || name == "tanh") {
26     if (auto callable{GetHostRuntimeWrapper<T, T>(name)}) {
27       return FoldElementalIntrinsic<T, T>(
28           context, std::move(funcRef), *callable);
29     } else {
30       context.messages().Say(
31           "%s(complex(kind=%d)) cannot be folded on host"_en_US, name, KIND);
32     }
33   } else if (name == "conjg") {
34     return FoldElementalIntrinsic<T, T>(
35         context, std::move(funcRef), &Scalar<T>::CONJG);
36   } else if (name == "cmplx") {
37     if (args.size() > 0 && args[0].has_value()) {
38       if (auto *x{UnwrapExpr<Expr<SomeComplex>>(args[0])}) {
39         // CMPLX(X [, KIND]) with complex X
40         return Fold(context, ConvertToType<T>(std::move(*x)));
41       } else {
42         // CMPLX(X [, Y [, KIND]]) with non-complex X
43         using Part = typename T::Part;
44         Expr<SomeType> re{std::move(*args[0].value().UnwrapExpr())};
45         Expr<SomeType> im{args.size() >= 2 && args[1].has_value()
46                 ? std::move(*args[1]->UnwrapExpr())
47                 : AsGenericExpr(Constant<Part>{Scalar<Part>{}})};
48         return Fold(context,
49             Expr<T>{
50                 ComplexConstructor<KIND>{ToReal<KIND>(context, std::move(re)),
51                     ToReal<KIND>(context, std::move(im))}});
52       }
53     }
54   } else if (name == "merge") {
55     return FoldMerge<T>(context, std::move(funcRef));
56   }
57   // TODO: cshift, dot_product, eoshift, matmul, pack, product,
58   // reduce, spread, sum, transfer, transpose, unpack
59   return Expr<T>{std::move(funcRef)};
60 }
61 
62 template <int KIND>
63 Expr<Type<TypeCategory::Complex, KIND>> FoldOperation(
64     FoldingContext &context, ComplexConstructor<KIND> &&x) {
65   if (auto array{ApplyElementwise(context, x)}) {
66     return *array;
67   }
68   using Result = Type<TypeCategory::Complex, KIND>;
69   if (auto folded{OperandsAreConstants(x)}) {
70     return Expr<Result>{
71         Constant<Result>{Scalar<Result>{folded->first, folded->second}}};
72   }
73   return Expr<Result>{std::move(x)};
74 }
75 
76 FOR_EACH_COMPLEX_KIND(template class ExpressionBase, )
77 template class ExpressionBase<SomeComplex>;
78 } // namespace Fortran::evaluate
79