1 //===-- lib/Evaluate/intrinsics-library.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 // This file defines host runtime functions that can be used for folding
10 // intrinsic functions.
11 // The default host runtime folders are built with <cmath> and
12 // <complex> functions that are guaranteed to exist from the C++ standard.
13
14 #include "flang/Evaluate/intrinsics-library.h"
15 #include "fold-implementation.h"
16 #include "host.h"
17 #include "flang/Common/static-multimap-view.h"
18 #include "flang/Evaluate/expression.h"
19 #include <cmath>
20 #include <complex>
21 #include <functional>
22 #include <type_traits>
23
24 namespace Fortran::evaluate {
25
26 // Define a vector like class that can hold an arbitrary number of
27 // Dynamic type and be built at compile time. This is like a
28 // std::vector<DynamicType>, but constexpr only.
29 template <typename... FortranType> struct TypeVectorStorage {
30 static constexpr DynamicType values[]{FortranType{}.GetType()...};
31 static constexpr const DynamicType *start{&values[0]};
32 static constexpr const DynamicType *end{start + sizeof...(FortranType)};
33 };
34 template <> struct TypeVectorStorage<> {
35 static constexpr const DynamicType *start{nullptr}, *end{nullptr};
36 };
37 struct TypeVector {
CreateFortran::evaluate::TypeVector38 template <typename... FortranType> static constexpr TypeVector Create() {
39 using storage = TypeVectorStorage<FortranType...>;
40 return TypeVector{storage::start, storage::end, sizeof...(FortranType)};
41 }
sizeFortran::evaluate::TypeVector42 constexpr size_t size() const { return size_; };
43 using const_iterator = const DynamicType *;
beginFortran::evaluate::TypeVector44 constexpr const_iterator begin() const { return startPtr; }
endFortran::evaluate::TypeVector45 constexpr const_iterator end() const { return endPtr; }
operator []Fortran::evaluate::TypeVector46 const DynamicType &operator[](size_t i) const { return *(startPtr + i); }
47
48 const DynamicType *startPtr{nullptr};
49 const DynamicType *endPtr{nullptr};
50 const size_t size_;
51 };
operator ==(const TypeVector & lhs,const std::vector<DynamicType> & rhs)52 inline bool operator==(
53 const TypeVector &lhs, const std::vector<DynamicType> &rhs) {
54 if (lhs.size() != rhs.size()) {
55 return false;
56 }
57 for (size_t i{0}; i < lhs.size(); ++i) {
58 if (lhs[i] != rhs[i]) {
59 return false;
60 }
61 }
62 return true;
63 }
64
65 // HostRuntimeFunction holds a pointer to a Folder function that can fold
66 // a Fortran scalar intrinsic using host runtime functions (e.g libm).
67 // The folder take care of all conversions between Fortran types and the related
68 // host types as well as setting and cleaning-up the floating point environment.
69 // HostRuntimeFunction are intended to be built at compile time (members are all
70 // constexpr constructible) so that they can be stored in a compile time static
71 // map.
72 struct HostRuntimeFunction {
73 using Folder = Expr<SomeType> (*)(
74 FoldingContext &, std::vector<Expr<SomeType>> &&);
75 using Key = std::string_view;
76 // Needed for implicit compare with keys.
operator KeyFortran::evaluate::HostRuntimeFunction77 constexpr operator Key() const { return key; }
78 // Name of the related Fortran intrinsic.
79 Key key;
80 // DynamicType of the Expr<SomeType> returns by folder.
81 DynamicType resultType;
82 // DynamicTypes expected for the Expr<SomeType> arguments of the folder.
83 // The folder will crash if provided arguments of different types.
84 TypeVector argumentTypes;
85 // Folder to be called to fold the intrinsic with host runtime. The provided
86 // Expr<SomeType> arguments must wrap scalar constants of the type described
87 // in argumentTypes, otherwise folder will crash. Any floating point issue
88 // raised while executing the host runtime will be reported in FoldingContext
89 // messages.
90 Folder folder;
91 };
92
93 // Translate a host function type signature (template arguments) into a
94 // constexpr data representation based on Fortran DynamicType that can be
95 // stored.
96 template <typename TR, typename... TA> using FuncPointer = TR (*)(TA...);
97 template <typename T> struct FuncTypeAnalyzer {};
98 template <typename HostTR, typename... HostTA>
99 struct FuncTypeAnalyzer<FuncPointer<HostTR, HostTA...>> {
100 static constexpr DynamicType result{host::FortranType<HostTR>{}.GetType()};
101 static constexpr TypeVector arguments{
102 TypeVector::Create<host::FortranType<HostTA>...>()};
103 };
104
105 // Define helpers to deal with host floating environment.
106 template <typename TR>
CheckFloatingPointIssues(host::HostFloatingPointEnvironment & hostFPE,const Scalar<TR> & x)107 static void CheckFloatingPointIssues(
108 host::HostFloatingPointEnvironment &hostFPE, const Scalar<TR> &x) {
109 if constexpr (TR::category == TypeCategory::Complex ||
110 TR::category == TypeCategory::Real) {
111 if (x.IsNotANumber()) {
112 hostFPE.SetFlag(RealFlag::InvalidArgument);
113 } else if (x.IsInfinite()) {
114 hostFPE.SetFlag(RealFlag::Overflow);
115 }
116 }
117 }
118 // Software Subnormal Flushing helper.
119 // Only flush floating-points. Forward other scalars untouched.
120 // Software flushing is only performed if hardware flushing is not available
121 // because it may not result in the same behavior as hardware flushing.
122 // Some runtime implementations are "working around" subnormal flushing to
123 // return results that they deem better than returning the result they would
124 // with a null argument. An example is logf that should return -inf if arguments
125 // are flushed to zero, but some implementations return -1.03972076416015625e2_4
126 // for all subnormal values instead. It is impossible to reproduce this with the
127 // simple software flushing below.
128 template <typename T>
FlushSubnormals(Scalar<T> && x)129 static constexpr inline const Scalar<T> FlushSubnormals(Scalar<T> &&x) {
130 if constexpr (T::category == TypeCategory::Real ||
131 T::category == TypeCategory::Complex) {
132 return x.FlushSubnormalToZero();
133 }
134 return x;
135 }
136
137 // This is the kernel called by all HostRuntimeFunction folders, it convert the
138 // Fortran Expr<SomeType> to the host runtime function argument types, calls
139 // the runtime function, and wrap back the result into an Expr<SomeType>.
140 // It deals with host floating point environment set-up and clean-up.
141 template <typename FuncType, typename TR, typename... TA, size_t... I>
ApplyHostFunctionHelper(FuncType func,FoldingContext & context,std::vector<Expr<SomeType>> && args,std::index_sequence<I...>)142 static Expr<SomeType> ApplyHostFunctionHelper(FuncType func,
143 FoldingContext &context, std::vector<Expr<SomeType>> &&args,
144 std::index_sequence<I...>) {
145 host::HostFloatingPointEnvironment hostFPE;
146 hostFPE.SetUpHostFloatingPointEnvironment(context);
147 host::HostType<TR> hostResult{};
148 Scalar<TR> result{};
149 std::tuple<Scalar<TA>...> scalarArgs{
150 GetScalarConstantValue<TA>(args[I]).value()...};
151 if (context.flushSubnormalsToZero() &&
152 !hostFPE.hasSubnormalFlushingHardwareControl()) {
153 hostResult = func(host::CastFortranToHost<TA>(
154 FlushSubnormals<TA>(std::move(std::get<I>(scalarArgs))))...);
155 result = FlushSubnormals<TR>(host::CastHostToFortran<TR>(hostResult));
156 } else {
157 hostResult = func(host::CastFortranToHost<TA>(std::get<I>(scalarArgs))...);
158 result = host::CastHostToFortran<TR>(hostResult);
159 }
160 if (!hostFPE.hardwareFlagsAreReliable()) {
161 CheckFloatingPointIssues<TR>(hostFPE, result);
162 }
163 hostFPE.CheckAndRestoreFloatingPointEnvironment(context);
164 return AsGenericExpr(Constant<TR>(std::move(result)));
165 }
166 template <typename HostTR, typename... HostTA>
ApplyHostFunction(FuncPointer<HostTR,HostTA...> func,FoldingContext & context,std::vector<Expr<SomeType>> && args)167 Expr<SomeType> ApplyHostFunction(FuncPointer<HostTR, HostTA...> func,
168 FoldingContext &context, std::vector<Expr<SomeType>> &&args) {
169 return ApplyHostFunctionHelper<decltype(func), host::FortranType<HostTR>,
170 host::FortranType<HostTA>...>(
171 func, context, std::move(args), std::index_sequence_for<HostTA...>{});
172 }
173
174 // FolderFactory builds a HostRuntimeFunction for the host runtime function
175 // passed as a template argument.
176 // Its static member function "fold" is the resulting folder. It captures the
177 // host runtime function pointer and pass it to the host runtime function folder
178 // kernel.
179 template <typename HostFuncType, HostFuncType func> class FolderFactory {
180 public:
Create(const std::string_view & name)181 static constexpr HostRuntimeFunction Create(const std::string_view &name) {
182 return HostRuntimeFunction{name, FuncTypeAnalyzer<HostFuncType>::result,
183 FuncTypeAnalyzer<HostFuncType>::arguments, &Fold};
184 }
185
186 private:
Fold(FoldingContext & context,std::vector<Expr<SomeType>> && args)187 static Expr<SomeType> Fold(
188 FoldingContext &context, std::vector<Expr<SomeType>> &&args) {
189 return ApplyHostFunction(func, context, std::move(args));
190 }
191 };
192
193 // Define host runtime libraries that can be used for folding and
194 // fill their description if they are available.
195 enum class LibraryVersion { Libm, PgmathFast, PgmathRelaxed, PgmathPrecise };
196 template <typename HostT, LibraryVersion> struct HostRuntimeLibrary {
197 // When specialized, this class holds a static constexpr table containing
198 // all the HostRuntimeLibrary for functions of library LibraryVersion
199 // that returns a value of type HostT.
200 };
201
202 using HostRuntimeMap = common::StaticMultimapView<HostRuntimeFunction>;
203
204 // Map numerical intrinsic to <cmath>/<complex> functions
205 template <typename HostT>
206 struct HostRuntimeLibrary<HostT, LibraryVersion::Libm> {
207 using F = FuncPointer<HostT, HostT>;
208 using F2 = FuncPointer<HostT, HostT, HostT>;
209 using ComplexToRealF = FuncPointer<HostT, const std::complex<HostT> &>;
210 static constexpr HostRuntimeFunction table[]{
211 FolderFactory<ComplexToRealF, ComplexToRealF{std::abs}>::Create("abs"),
212 FolderFactory<F, F{std::acos}>::Create("acos"),
213 FolderFactory<F, F{std::acosh}>::Create("acosh"),
214 FolderFactory<F, F{std::asin}>::Create("asin"),
215 FolderFactory<F, F{std::asinh}>::Create("asinh"),
216 FolderFactory<F, F{std::atan}>::Create("atan"),
217 FolderFactory<F2, F2{std::atan2}>::Create("atan2"),
218 FolderFactory<F, F{std::atanh}>::Create("atanh"),
219 FolderFactory<F, F{std::cos}>::Create("cos"),
220 FolderFactory<F, F{std::cosh}>::Create("cosh"),
221 FolderFactory<F, F{std::erf}>::Create("erf"),
222 FolderFactory<F, F{std::erfc}>::Create("erfc"),
223 FolderFactory<F, F{std::exp}>::Create("exp"),
224 FolderFactory<F, F{std::tgamma}>::Create("gamma"),
225 FolderFactory<F, F{std::log}>::Create("log"),
226 FolderFactory<F, F{std::log10}>::Create("log10"),
227 FolderFactory<F, F{std::lgamma}>::Create("log_gamma"),
228 FolderFactory<F2, F2{std::fmod}>::Create("mod"),
229 FolderFactory<F2, F2{std::pow}>::Create("pow"),
230 FolderFactory<F, F{std::sin}>::Create("sin"),
231 FolderFactory<F, F{std::sinh}>::Create("sinh"),
232 FolderFactory<F, F{std::tan}>::Create("tan"),
233 FolderFactory<F, F{std::tanh}>::Create("tanh"),
234 };
235 // Note: cmath does not have modulo and erfc_scaled equivalent
236
237 // Note regarding lack of bessel function support:
238 // C++17 defined standard Bessel math functions std::cyl_bessel_j
239 // and std::cyl_neumann that can be used for Fortran j and y
240 // bessel functions. However, they are not yet implemented in
241 // clang libc++ (ok in GNU libstdc++). C maths functions j0...
242 // are not C standard but a GNU extension so they are not used
243 // to avoid introducing incompatibilities.
244 // Use libpgmath to get bessel function folding support.
245 // TODO: Add Bessel functions when possible.
246 static constexpr HostRuntimeMap map{table};
247 static_assert(map.Verify(), "map must be sorted");
248 };
249 template <typename HostT>
250 struct HostRuntimeLibrary<std::complex<HostT>, LibraryVersion::Libm> {
251 using F = FuncPointer<std::complex<HostT>, const std::complex<HostT> &>;
252 using F2 = FuncPointer<std::complex<HostT>, const std::complex<HostT> &,
253 const std::complex<HostT> &>;
254 using F2A = FuncPointer<std::complex<HostT>, const HostT &,
255 const std::complex<HostT> &>;
256 using F2B = FuncPointer<std::complex<HostT>, const std::complex<HostT> &,
257 const HostT &>;
258 static constexpr HostRuntimeFunction table[]{
259 FolderFactory<F, F{std::acos}>::Create("acos"),
260 FolderFactory<F, F{std::acosh}>::Create("acosh"),
261 FolderFactory<F, F{std::asin}>::Create("asin"),
262 FolderFactory<F, F{std::asinh}>::Create("asinh"),
263 FolderFactory<F, F{std::atan}>::Create("atan"),
264 FolderFactory<F, F{std::atanh}>::Create("atanh"),
265 FolderFactory<F, F{std::cos}>::Create("cos"),
266 FolderFactory<F, F{std::cosh}>::Create("cosh"),
267 FolderFactory<F, F{std::exp}>::Create("exp"),
268 FolderFactory<F, F{std::log}>::Create("log"),
269 FolderFactory<F2, F2{std::pow}>::Create("pow"),
270 FolderFactory<F2A, F2A{std::pow}>::Create("pow"),
271 FolderFactory<F2B, F2B{std::pow}>::Create("pow"),
272 FolderFactory<F, F{std::sin}>::Create("sin"),
273 FolderFactory<F, F{std::sinh}>::Create("sinh"),
274 FolderFactory<F, F{std::sqrt}>::Create("sqrt"),
275 FolderFactory<F, F{std::tan}>::Create("tan"),
276 FolderFactory<F, F{std::tanh}>::Create("tanh"),
277 };
278 static constexpr HostRuntimeMap map{table};
279 static_assert(map.Verify(), "map must be sorted");
280 };
281
282 /// Define pgmath description
283 #if LINK_WITH_LIBPGMATH
284 // Only use libpgmath for folding if it is available.
285 // First declare all libpgmaths functions
286 #define PGMATH_LINKING
287 #define PGMATH_DECLARE
288 #include "flang/Evaluate/pgmath.h.inc"
289
290 #define REAL_FOLDER(name, func) \
291 FolderFactory<decltype(&func), &func>::Create(#name)
292 template <> struct HostRuntimeLibrary<float, LibraryVersion::PgmathFast> {
293 static constexpr HostRuntimeFunction table[]{
294 #define PGMATH_FAST
295 #define PGMATH_USE_S(name, func) REAL_FOLDER(name, func),
296 #include "flang/Evaluate/pgmath.h.inc"
297 };
298 static constexpr HostRuntimeMap map{table};
299 static_assert(map.Verify(), "map must be sorted");
300 };
301 template <> struct HostRuntimeLibrary<double, LibraryVersion::PgmathFast> {
302 static constexpr HostRuntimeFunction table[]{
303 #define PGMATH_FAST
304 #define PGMATH_USE_D(name, func) REAL_FOLDER(name, func),
305 #include "flang/Evaluate/pgmath.h.inc"
306 };
307 static constexpr HostRuntimeMap map{table};
308 static_assert(map.Verify(), "map must be sorted");
309 };
310 template <> struct HostRuntimeLibrary<float, LibraryVersion::PgmathRelaxed> {
311 static constexpr HostRuntimeFunction table[]{
312 #define PGMATH_RELAXED
313 #define PGMATH_USE_S(name, func) REAL_FOLDER(name, func),
314 #include "flang/Evaluate/pgmath.h.inc"
315 };
316 static constexpr HostRuntimeMap map{table};
317 static_assert(map.Verify(), "map must be sorted");
318 };
319 template <> struct HostRuntimeLibrary<double, LibraryVersion::PgmathRelaxed> {
320 static constexpr HostRuntimeFunction table[]{
321 #define PGMATH_RELAXED
322 #define PGMATH_USE_D(name, func) REAL_FOLDER(name, func),
323 #include "flang/Evaluate/pgmath.h.inc"
324 };
325 static constexpr HostRuntimeMap map{table};
326 static_assert(map.Verify(), "map must be sorted");
327 };
328 template <> struct HostRuntimeLibrary<float, LibraryVersion::PgmathPrecise> {
329 static constexpr HostRuntimeFunction table[]{
330 #define PGMATH_PRECISE
331 #define PGMATH_USE_S(name, func) REAL_FOLDER(name, func),
332 #include "flang/Evaluate/pgmath.h.inc"
333 };
334 static constexpr HostRuntimeMap map{table};
335 static_assert(map.Verify(), "map must be sorted");
336 };
337 template <> struct HostRuntimeLibrary<double, LibraryVersion::PgmathPrecise> {
338 static constexpr HostRuntimeFunction table[]{
339 #define PGMATH_PRECISE
340 #define PGMATH_USE_D(name, func) REAL_FOLDER(name, func),
341 #include "flang/Evaluate/pgmath.h.inc"
342 };
343 static constexpr HostRuntimeMap map{table};
344 static_assert(map.Verify(), "map must be sorted");
345 };
346
347 // TODO: double _Complex/float _Complex have been removed from llvm flang
348 // pgmath.h.inc because they caused warnings, they need to be added back
349 // so that the complex pgmath versions can be used when requested.
350
351 #endif /* LINK_WITH_LIBPGMATH */
352
353 // Helper to check if a HostRuntimeLibrary specialization exists
354 template <typename T, typename = void> struct IsAvailable : std::false_type {};
355 template <typename T>
356 struct IsAvailable<T, decltype((void)T::table, void())> : std::true_type {};
357 // Define helpers to find host runtime library map according to desired version
358 // and type.
359 template <typename HostT, LibraryVersion version>
GetHostRuntimeMapHelper(DynamicType resultType)360 static const HostRuntimeMap *GetHostRuntimeMapHelper(
361 [[maybe_unused]] DynamicType resultType) {
362 // A library must only be instantiated if LibraryVersion is
363 // available on the host and if HostT maps to a Fortran type.
364 // For instance, whenever long double and double are both 64-bits, double
365 // is mapped to Fortran 64bits real type, and long double will be left
366 // unmapped.
367 if constexpr (host::FortranTypeExists<HostT>()) {
368 using Lib = HostRuntimeLibrary<HostT, version>;
369 if constexpr (IsAvailable<Lib>::value) {
370 if (host::FortranType<HostT>{}.GetType() == resultType) {
371 return &Lib::map;
372 }
373 }
374 }
375 return nullptr;
376 }
377 template <LibraryVersion version>
GetHostRuntimeMapVersion(DynamicType resultType)378 static const HostRuntimeMap *GetHostRuntimeMapVersion(DynamicType resultType) {
379 if (resultType.category() == TypeCategory::Real) {
380 if (const auto *map{GetHostRuntimeMapHelper<float, version>(resultType)}) {
381 return map;
382 }
383 if (const auto *map{GetHostRuntimeMapHelper<double, version>(resultType)}) {
384 return map;
385 }
386 if (const auto *map{
387 GetHostRuntimeMapHelper<long double, version>(resultType)}) {
388 return map;
389 }
390 }
391 if (resultType.category() == TypeCategory::Complex) {
392 if (const auto *map{GetHostRuntimeMapHelper<std::complex<float>, version>(
393 resultType)}) {
394 return map;
395 }
396 if (const auto *map{GetHostRuntimeMapHelper<std::complex<double>, version>(
397 resultType)}) {
398 return map;
399 }
400 if (const auto *map{
401 GetHostRuntimeMapHelper<std::complex<long double>, version>(
402 resultType)}) {
403 return map;
404 }
405 }
406 return nullptr;
407 }
GetHostRuntimeMap(LibraryVersion version,DynamicType resultType)408 static const HostRuntimeMap *GetHostRuntimeMap(
409 LibraryVersion version, DynamicType resultType) {
410 switch (version) {
411 case LibraryVersion::Libm:
412 return GetHostRuntimeMapVersion<LibraryVersion::Libm>(resultType);
413 case LibraryVersion::PgmathPrecise:
414 return GetHostRuntimeMapVersion<LibraryVersion::PgmathPrecise>(resultType);
415 case LibraryVersion::PgmathRelaxed:
416 return GetHostRuntimeMapVersion<LibraryVersion::PgmathRelaxed>(resultType);
417 case LibraryVersion::PgmathFast:
418 return GetHostRuntimeMapVersion<LibraryVersion::PgmathFast>(resultType);
419 }
420 return nullptr;
421 }
422
SearchInHostRuntimeMap(const HostRuntimeMap & map,const std::string & name,DynamicType resultType,const std::vector<DynamicType> & argTypes)423 static const HostRuntimeFunction *SearchInHostRuntimeMap(
424 const HostRuntimeMap &map, const std::string &name, DynamicType resultType,
425 const std::vector<DynamicType> &argTypes) {
426 auto sameNameRange{map.equal_range(name)};
427 for (const auto *iter{sameNameRange.first}; iter != sameNameRange.second;
428 ++iter) {
429 if (iter->resultType == resultType && iter->argumentTypes == argTypes) {
430 return &*iter;
431 }
432 }
433 return nullptr;
434 }
435
436 // Search host runtime libraries for an exact type match.
SearchHostRuntime(const std::string & name,DynamicType resultType,const std::vector<DynamicType> & argTypes)437 static const HostRuntimeFunction *SearchHostRuntime(const std::string &name,
438 DynamicType resultType, const std::vector<DynamicType> &argTypes) {
439 // TODO: When command line options regarding targeted numerical library is
440 // available, this needs to be revisited to take it into account. So far,
441 // default to libpgmath if F18 is built with it.
442 #if LINK_WITH_LIBPGMATH
443 if (const auto *map{
444 GetHostRuntimeMap(LibraryVersion::PgmathPrecise, resultType)}) {
445 if (const auto *hostFunction{
446 SearchInHostRuntimeMap(*map, name, resultType, argTypes)}) {
447 return hostFunction;
448 }
449 }
450 // Default to libm if functions or types are not available in pgmath.
451 #endif
452 if (const auto *map{GetHostRuntimeMap(LibraryVersion::Libm, resultType)}) {
453 if (const auto *hostFunction{
454 SearchInHostRuntimeMap(*map, name, resultType, argTypes)}) {
455 return hostFunction;
456 }
457 }
458 return nullptr;
459 }
460
461 // Return a DynamicType that can hold all values of a given type.
462 // This is used to allow 16bit float to be folded with 32bits and
463 // x87 float to be folded with IEEE 128bits.
BiggerType(DynamicType type)464 static DynamicType BiggerType(DynamicType type) {
465 if (type.category() == TypeCategory::Real ||
466 type.category() == TypeCategory::Complex) {
467 // 16 bits floats to IEEE 32 bits float
468 if (type.kind() == common::RealKindForPrecision(11) ||
469 type.kind() == common::RealKindForPrecision(8)) {
470 return {type.category(), common::RealKindForPrecision(24)};
471 }
472 // x87 float to IEEE 128 bits float
473 if (type.kind() == common::RealKindForPrecision(64)) {
474 return {type.category(), common::RealKindForPrecision(113)};
475 }
476 }
477 return type;
478 }
479
GetHostRuntimeWrapper(const std::string & name,DynamicType resultType,const std::vector<DynamicType> & argTypes)480 std::optional<HostRuntimeWrapper> GetHostRuntimeWrapper(const std::string &name,
481 DynamicType resultType, const std::vector<DynamicType> &argTypes) {
482 if (const auto *hostFunction{SearchHostRuntime(name, resultType, argTypes)}) {
483 return hostFunction->folder;
484 }
485 // If no exact match, search with "bigger" types and insert type
486 // conversions around the folder.
487 std::vector<evaluate::DynamicType> biggerArgTypes;
488 evaluate::DynamicType biggerResultType{BiggerType(resultType)};
489 for (auto type : argTypes) {
490 biggerArgTypes.emplace_back(BiggerType(type));
491 }
492 if (const auto *hostFunction{
493 SearchHostRuntime(name, biggerResultType, biggerArgTypes)}) {
494 return [hostFunction, resultType](
495 FoldingContext &context, std::vector<Expr<SomeType>> &&args) {
496 auto nArgs{args.size()};
497 for (size_t i{0}; i < nArgs; ++i) {
498 args[i] = Fold(context,
499 ConvertToType(hostFunction->argumentTypes[i], std::move(args[i]))
500 .value());
501 }
502 return Fold(context,
503 ConvertToType(
504 resultType, hostFunction->folder(context, std::move(args)))
505 .value());
506 };
507 }
508 return std::nullopt;
509 }
510 } // namespace Fortran::evaluate
511