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llvm-project/flang/lib/Evaluate/fold-implementation.h

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//===-- lib/Evaluate/fold-implementation.h --------------------------------===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
#ifndef FORTRAN_EVALUATE_FOLD_IMPLEMENTATION_H_
#define FORTRAN_EVALUATE_FOLD_IMPLEMENTATION_H_
#include "character.h"
#include "host.h"
#include "int-power.h"
#include "flang/Common/indirection.h"
#include "flang/Common/template.h"
#include "flang/Common/unwrap.h"
#include "flang/Evaluate/characteristics.h"
#include "flang/Evaluate/common.h"
#include "flang/Evaluate/constant.h"
#include "flang/Evaluate/expression.h"
#include "flang/Evaluate/fold.h"
#include "flang/Evaluate/formatting.h"
#include "flang/Evaluate/intrinsics-library.h"
#include "flang/Evaluate/intrinsics.h"
#include "flang/Evaluate/shape.h"
#include "flang/Evaluate/tools.h"
#include "flang/Evaluate/traverse.h"
#include "flang/Evaluate/type.h"
#include "flang/Parser/message.h"
#include "flang/Semantics/scope.h"
#include "flang/Semantics/symbol.h"
#include "flang/Semantics/tools.h"
#include <algorithm>
#include <cmath>
#include <complex>
#include <cstdio>
#include <optional>
#include <type_traits>
#include <variant>
// Some environments, viz. clang on Darwin, allow the macro HUGE
// to leak out of <math.h> even when it is never directly included.
#undef HUGE
namespace Fortran::evaluate {
// Utilities
template <typename T> class Folder {
public:
explicit Folder(FoldingContext &c) : context_{c} {}
std::optional<Constant<T>> GetNamedConstant(const Symbol &);
std::optional<Constant<T>> ApplySubscripts(const Constant<T> &array,
const std::vector<Constant<SubscriptInteger>> &subscripts);
std::optional<Constant<T>> ApplyComponent(Constant<SomeDerived> &&,
const Symbol &component,
const std::vector<Constant<SubscriptInteger>> * = nullptr);
std::optional<Constant<T>> GetConstantComponent(
Component &, const std::vector<Constant<SubscriptInteger>> * = nullptr);
std::optional<Constant<T>> Folding(ArrayRef &);
Expr<T> Folding(Designator<T> &&);
Constant<T> *Folding(std::optional<ActualArgument> &);
Expr<T> Reshape(FunctionRef<T> &&);
private:
FoldingContext &context_;
};
std::optional<Constant<SubscriptInteger>> GetConstantSubscript(
FoldingContext &, Subscript &, const NamedEntity &, int dim);
// Helper to use host runtime on scalars for folding.
template <typename TR, typename... TA>
std::optional<std::function<Scalar<TR>(FoldingContext &, Scalar<TA>...)>>
GetHostRuntimeWrapper(const std::string &name) {
std::vector<DynamicType> argTypes{TA{}.GetType()...};
if (auto hostWrapper{GetHostRuntimeWrapper(name, TR{}.GetType(), argTypes)}) {
return [hostWrapper](
FoldingContext &context, Scalar<TA>... args) -> Scalar<TR> {
std::vector<Expr<SomeType>> genericArgs{
AsGenericExpr(Constant<TA>{args})...};
return GetScalarConstantValue<TR>(
(*hostWrapper)(context, std::move(genericArgs)))
.value();
};
}
return std::nullopt;
}
// FoldOperation() rewrites expression tree nodes.
// If there is any possibility that the rewritten node will
// not have the same representation type, the result of
// FoldOperation() will be packaged in an Expr<> of the same
// specific type.
// no-op base case
template <typename A>
common::IfNoLvalue<Expr<ResultType<A>>, A> FoldOperation(
FoldingContext &, A &&x) {
static_assert(!std::is_same_v<A, Expr<ResultType<A>>>,
"call Fold() instead for Expr<>");
return Expr<ResultType<A>>{std::move(x)};
}
Component FoldOperation(FoldingContext &, Component &&);
NamedEntity FoldOperation(FoldingContext &, NamedEntity &&);
Triplet FoldOperation(FoldingContext &, Triplet &&);
Subscript FoldOperation(FoldingContext &, Subscript &&);
ArrayRef FoldOperation(FoldingContext &, ArrayRef &&);
CoarrayRef FoldOperation(FoldingContext &, CoarrayRef &&);
DataRef FoldOperation(FoldingContext &, DataRef &&);
Substring FoldOperation(FoldingContext &, Substring &&);
ComplexPart FoldOperation(FoldingContext &, ComplexPart &&);
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&);
template <int KIND>
Expr<Type<TypeCategory::Integer, KIND>> FoldIntrinsicFunction(
FoldingContext &context, FunctionRef<Type<TypeCategory::Integer, KIND>> &&);
template <int KIND>
Expr<Type<TypeCategory::Real, KIND>> FoldIntrinsicFunction(
FoldingContext &context, FunctionRef<Type<TypeCategory::Real, KIND>> &&);
template <int KIND>
Expr<Type<TypeCategory::Complex, KIND>> FoldIntrinsicFunction(
FoldingContext &context, FunctionRef<Type<TypeCategory::Complex, KIND>> &&);
template <int KIND>
Expr<Type<TypeCategory::Logical, KIND>> FoldIntrinsicFunction(
FoldingContext &context, FunctionRef<Type<TypeCategory::Logical, KIND>> &&);
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Designator<T> &&designator) {
return Folder<T>{context}.Folding(std::move(designator));
}
Expr<TypeParamInquiry::Result> FoldOperation(
FoldingContext &, TypeParamInquiry &&);
Expr<ImpliedDoIndex::Result> FoldOperation(
FoldingContext &context, ImpliedDoIndex &&);
template <typename T>
Expr<T> FoldOperation(FoldingContext &, ArrayConstructor<T> &&);
Expr<SomeDerived> FoldOperation(FoldingContext &, StructureConstructor &&);
template <typename T>
std::optional<Constant<T>> Folder<T>::GetNamedConstant(const Symbol &symbol0) {
const Symbol &symbol{ResolveAssociations(symbol0)};
if (IsNamedConstant(symbol)) {
if (const auto *object{
symbol.detailsIf<semantics::ObjectEntityDetails>()}) {
if (const auto *constant{UnwrapConstantValue<T>(object->init())}) {
return *constant;
}
}
}
return std::nullopt;
}
template <typename T>
std::optional<Constant<T>> Folder<T>::Folding(ArrayRef &aRef) {
std::vector<Constant<SubscriptInteger>> subscripts;
int dim{0};
for (Subscript &ss : aRef.subscript()) {
if (auto constant{GetConstantSubscript(context_, ss, aRef.base(), dim++)}) {
subscripts.emplace_back(std::move(*constant));
} else {
return std::nullopt;
}
}
if (Component * component{aRef.base().UnwrapComponent()}) {
return GetConstantComponent(*component, &subscripts);
} else if (std::optional<Constant<T>> array{
GetNamedConstant(aRef.base().GetLastSymbol())}) {
return ApplySubscripts(*array, subscripts);
} else {
return std::nullopt;
}
}
template <typename T>
std::optional<Constant<T>> Folder<T>::ApplySubscripts(const Constant<T> &array,
const std::vector<Constant<SubscriptInteger>> &subscripts) {
const auto &shape{array.shape()};
const auto &lbounds{array.lbounds()};
int rank{GetRank(shape)};
CHECK(rank == static_cast<int>(subscripts.size()));
std::size_t elements{1};
ConstantSubscripts resultShape;
ConstantSubscripts ssLB;
for (const auto &ss : subscripts) {
CHECK(ss.Rank() <= 1);
if (ss.Rank() == 1) {
resultShape.push_back(static_cast<ConstantSubscript>(ss.size()));
elements *= ss.size();
ssLB.push_back(ss.lbounds().front());
}
}
ConstantSubscripts ssAt(rank, 0), at(rank, 0), tmp(1, 0);
std::vector<Scalar<T>> values;
while (elements-- > 0) {
bool increment{true};
int k{0};
for (int j{0}; j < rank; ++j) {
if (subscripts[j].Rank() == 0) {
at[j] = subscripts[j].GetScalarValue().value().ToInt64();
} else {
CHECK(k < GetRank(resultShape));
tmp[0] = ssLB.at(k) + ssAt.at(k);
at[j] = subscripts[j].At(tmp).ToInt64();
if (increment) {
if (++ssAt[k] == resultShape[k]) {
ssAt[k] = 0;
} else {
increment = false;
}
}
++k;
}
if (at[j] < lbounds[j] || at[j] >= lbounds[j] + shape[j]) {
context_.messages().Say(
"Subscript value (%jd) is out of range on dimension %d in reference to a constant array value"_err_en_US,
at[j], j + 1);
return std::nullopt;
}
}
values.emplace_back(array.At(at));
CHECK(!increment || elements == 0);
CHECK(k == GetRank(resultShape));
}
if constexpr (T::category == TypeCategory::Character) {
return Constant<T>{array.LEN(), std::move(values), std::move(resultShape)};
} else if constexpr (std::is_same_v<T, SomeDerived>) {
return Constant<T>{array.result().derivedTypeSpec(), std::move(values),
std::move(resultShape)};
} else {
return Constant<T>{std::move(values), std::move(resultShape)};
}
}
template <typename T>
std::optional<Constant<T>> Folder<T>::ApplyComponent(
Constant<SomeDerived> &&structures, const Symbol &component,
const std::vector<Constant<SubscriptInteger>> *subscripts) {
if (auto scalar{structures.GetScalarValue()}) {
if (std::optional<Expr<SomeType>> expr{scalar->Find(component)}) {
if (const Constant<T> *value{UnwrapConstantValue<T>(expr.value())}) {
if (!subscripts) {
return std::move(*value);
} else {
return ApplySubscripts(*value, *subscripts);
}
}
}
} else {
// A(:)%scalar_component & A(:)%array_component(subscripts)
std::unique_ptr<ArrayConstructor<T>> array;
if (structures.empty()) {
return std::nullopt;
}
ConstantSubscripts at{structures.lbounds()};
do {
StructureConstructor scalar{structures.At(at)};
if (std::optional<Expr<SomeType>> expr{scalar.Find(component)}) {
if (const Constant<T> *value{UnwrapConstantValue<T>(expr.value())}) {
if (!array.get()) {
// This technique ensures that character length or derived type
// information is propagated to the array constructor.
auto *typedExpr{UnwrapExpr<Expr<T>>(expr.value())};
CHECK(typedExpr);
array = std::make_unique<ArrayConstructor<T>>(*typedExpr);
}
if (subscripts) {
if (auto element{ApplySubscripts(*value, *subscripts)}) {
CHECK(element->Rank() == 0);
array->Push(Expr<T>{std::move(*element)});
} else {
return std::nullopt;
}
} else {
CHECK(value->Rank() == 0);
array->Push(Expr<T>{*value});
}
} else {
return std::nullopt;
}
}
} while (structures.IncrementSubscripts(at));
// Fold the ArrayConstructor<> into a Constant<>.
CHECK(array);
Expr<T> result{Fold(context_, Expr<T>{std::move(*array)})};
if (auto *constant{UnwrapConstantValue<T>(result)}) {
return constant->Reshape(common::Clone(structures.shape()));
}
}
return std::nullopt;
}
template <typename T>
std::optional<Constant<T>> Folder<T>::GetConstantComponent(Component &component,
const std::vector<Constant<SubscriptInteger>> *subscripts) {
if (std::optional<Constant<SomeDerived>> structures{std::visit(
common::visitors{
[&](const Symbol &symbol) {
return Folder<SomeDerived>{context_}.GetNamedConstant(symbol);
},
[&](ArrayRef &aRef) {
return Folder<SomeDerived>{context_}.Folding(aRef);
},
[&](Component &base) {
return Folder<SomeDerived>{context_}.GetConstantComponent(base);
},
[&](CoarrayRef &) {
return std::optional<Constant<SomeDerived>>{};
},
},
component.base().u)}) {
return ApplyComponent(
std::move(*structures), component.GetLastSymbol(), subscripts);
} else {
return std::nullopt;
}
}
template <typename T> Expr<T> Folder<T>::Folding(Designator<T> &&designator) {
if constexpr (T::category == TypeCategory::Character) {
if (auto *substring{common::Unwrap<Substring>(designator.u)}) {
if (std::optional<Expr<SomeCharacter>> folded{
substring->Fold(context_)}) {
if (auto value{GetScalarConstantValue<T>(*folded)}) {
return Expr<T>{*value};
}
}
if (auto length{ToInt64(Fold(context_, substring->LEN()))}) {
if (*length == 0) {
return Expr<T>{Constant<T>{Scalar<T>{}}};
}
}
}
}
return std::visit(
common::visitors{
[&](SymbolRef &&symbol) {
if (auto constant{GetNamedConstant(*symbol)}) {
return Expr<T>{std::move(*constant)};
}
return Expr<T>{std::move(designator)};
},
[&](ArrayRef &&aRef) {
aRef = FoldOperation(context_, std::move(aRef));
if (auto c{Folding(aRef)}) {
return Expr<T>{std::move(*c)};
} else {
return Expr<T>{Designator<T>{std::move(aRef)}};
}
},
[&](Component &&component) {
component = FoldOperation(context_, std::move(component));
if (auto c{GetConstantComponent(component)}) {
return Expr<T>{std::move(*c)};
} else {
return Expr<T>{Designator<T>{std::move(component)}};
}
},
[&](auto &&x) {
return Expr<T>{
Designator<T>{FoldOperation(context_, std::move(x))}};
},
},
std::move(designator.u));
}
// Apply type conversion and re-folding if necessary.
// This is where BOZ arguments are converted.
template <typename T>
Constant<T> *Folder<T>::Folding(std::optional<ActualArgument> &arg) {
if (auto *expr{UnwrapExpr<Expr<SomeType>>(arg)}) {
if (!UnwrapExpr<Expr<T>>(*expr)) {
if (auto converted{ConvertToType(T::GetType(), std::move(*expr))}) {
*expr = Fold(context_, std::move(*converted));
}
}
return UnwrapConstantValue<T>(*expr);
}
return nullptr;
}
template <typename... A, std::size_t... I>
std::optional<std::tuple<const Constant<A> *...>> GetConstantArgumentsHelper(
FoldingContext &context, ActualArguments &arguments,
std::index_sequence<I...>) {
static_assert(
(... && IsSpecificIntrinsicType<A>)); // TODO derived types for MERGE?
static_assert(sizeof...(A) > 0);
std::tuple<const Constant<A> *...> args{
Folder<A>{context}.Folding(arguments.at(I))...};
if ((... && (std::get<I>(args)))) {
return args;
} else {
return std::nullopt;
}
}
template <typename... A>
std::optional<std::tuple<const Constant<A> *...>> GetConstantArguments(
FoldingContext &context, ActualArguments &args) {
return GetConstantArgumentsHelper<A...>(
context, args, std::index_sequence_for<A...>{});
}
template <typename... A, std::size_t... I>
std::optional<std::tuple<Scalar<A>...>> GetScalarConstantArgumentsHelper(
FoldingContext &context, ActualArguments &args, std::index_sequence<I...>) {
if (auto constArgs{GetConstantArguments<A...>(context, args)}) {
return std::tuple<Scalar<A>...>{
std::get<I>(*constArgs)->GetScalarValue().value()...};
} else {
return std::nullopt;
}
}
template <typename... A>
std::optional<std::tuple<Scalar<A>...>> GetScalarConstantArguments(
FoldingContext &context, ActualArguments &args) {
return GetScalarConstantArgumentsHelper<A...>(
context, args, std::index_sequence_for<A...>{});
}
// helpers to fold intrinsic function references
// Define callable types used in a common utility that
// takes care of array and cast/conversion aspects for elemental intrinsics
template <typename TR, typename... TArgs>
using ScalarFunc = std::function<Scalar<TR>(const Scalar<TArgs> &...)>;
template <typename TR, typename... TArgs>
using ScalarFuncWithContext =
std::function<Scalar<TR>(FoldingContext &, const Scalar<TArgs> &...)>;
template <template <typename, typename...> typename WrapperType, typename TR,
typename... TA, std::size_t... I>
Expr<TR> FoldElementalIntrinsicHelper(FoldingContext &context,
FunctionRef<TR> &&funcRef, WrapperType<TR, TA...> func,
std::index_sequence<I...>) {
if (std::optional<std::tuple<const Constant<TA> *...>> args{
GetConstantArguments<TA...>(context, funcRef.arguments())}) {
// Compute the shape of the result based on shapes of arguments
ConstantSubscripts shape;
int rank{0};
const ConstantSubscripts *shapes[]{&std::get<I>(*args)->shape()...};
const int ranks[]{std::get<I>(*args)->Rank()...};
for (unsigned int i{0}; i < sizeof...(TA); ++i) {
if (ranks[i] > 0) {
if (rank == 0) {
rank = ranks[i];
shape = *shapes[i];
} else {
if (shape != *shapes[i]) {
// TODO: Rank compatibility was already checked but it seems to be
// the first place where the actual shapes are checked to be the
// same. Shouldn't this be checked elsewhere so that this is also
// checked for non constexpr call to elemental intrinsics function?
context.messages().Say(
"Arguments in elemental intrinsic function are not conformable"_err_en_US);
return Expr<TR>{std::move(funcRef)};
}
}
}
}
CHECK(rank == GetRank(shape));
// Compute all the scalar values of the results
std::vector<Scalar<TR>> results;
if (TotalElementCount(shape) > 0) {
ConstantBounds bounds{shape};
ConstantSubscripts resultIndex(rank, 1);
ConstantSubscripts argIndex[]{std::get<I>(*args)->lbounds()...};
do {
if constexpr (std::is_same_v<WrapperType<TR, TA...>,
ScalarFuncWithContext<TR, TA...>>) {
results.emplace_back(
func(context, std::get<I>(*args)->At(argIndex[I])...));
} else if constexpr (std::is_same_v<WrapperType<TR, TA...>,
ScalarFunc<TR, TA...>>) {
results.emplace_back(func(std::get<I>(*args)->At(argIndex[I])...));
}
(std::get<I>(*args)->IncrementSubscripts(argIndex[I]), ...);
} while (bounds.IncrementSubscripts(resultIndex));
}
// Build and return constant result
if constexpr (TR::category == TypeCategory::Character) {
auto len{static_cast<ConstantSubscript>(
results.size() ? results[0].length() : 0)};
return Expr<TR>{Constant<TR>{len, std::move(results), std::move(shape)}};
} else {
return Expr<TR>{Constant<TR>{std::move(results), std::move(shape)}};
}
}
return Expr<TR>{std::move(funcRef)};
}
template <typename TR, typename... TA>
Expr<TR> FoldElementalIntrinsic(FoldingContext &context,
FunctionRef<TR> &&funcRef, ScalarFunc<TR, TA...> func) {
return FoldElementalIntrinsicHelper<ScalarFunc, TR, TA...>(
context, std::move(funcRef), func, std::index_sequence_for<TA...>{});
}
template <typename TR, typename... TA>
Expr<TR> FoldElementalIntrinsic(FoldingContext &context,
FunctionRef<TR> &&funcRef, ScalarFuncWithContext<TR, TA...> func) {
return FoldElementalIntrinsicHelper<ScalarFuncWithContext, TR, TA...>(
context, std::move(funcRef), func, std::index_sequence_for<TA...>{});
}
std::optional<std::int64_t> GetInt64Arg(const std::optional<ActualArgument> &);
std::optional<std::int64_t> GetInt64ArgOr(
const std::optional<ActualArgument> &, std::int64_t defaultValue);
template <typename A, typename B>
std::optional<std::vector<A>> GetIntegerVector(const B &x) {
static_assert(std::is_integral_v<A>);
if (const auto *someInteger{UnwrapExpr<Expr<SomeInteger>>(x)}) {
return std::visit(
[](const auto &typedExpr) -> std::optional<std::vector<A>> {
using T = ResultType<decltype(typedExpr)>;
if (const auto *constant{UnwrapConstantValue<T>(typedExpr)}) {
if (constant->Rank() == 1) {
std::vector<A> result;
for (const auto &value : constant->values()) {
result.push_back(static_cast<A>(value.ToInt64()));
}
return result;
}
}
return std::nullopt;
},
someInteger->u);
}
return std::nullopt;
}
// Transform an intrinsic function reference that contains user errors
// into an intrinsic with the same characteristic but the "invalid" name.
// This to prevent generating warnings over and over if the expression
// gets re-folded.
template <typename T> Expr<T> MakeInvalidIntrinsic(FunctionRef<T> &&funcRef) {
SpecificIntrinsic invalid{std::get<SpecificIntrinsic>(funcRef.proc().u)};
invalid.name = IntrinsicProcTable::InvalidName;
return Expr<T>{FunctionRef<T>{ProcedureDesignator{std::move(invalid)},
ActualArguments{std::move(funcRef.arguments())}}};
}
template <typename T> Expr<T> Folder<T>::Reshape(FunctionRef<T> &&funcRef) {
auto args{funcRef.arguments()};
CHECK(args.size() == 4);
const auto *source{UnwrapConstantValue<T>(args[0])};
const auto *pad{UnwrapConstantValue<T>(args[2])};
std::optional<std::vector<ConstantSubscript>> shape{
GetIntegerVector<ConstantSubscript>(args[1])};
std::optional<std::vector<int>> order{GetIntegerVector<int>(args[3])};
if (!source || !shape || (args[2] && !pad) || (args[3] && !order)) {
return Expr<T>{std::move(funcRef)}; // Non-constant arguments
} else if (shape.value().size() > common::maxRank) {
context_.messages().Say(
"Size of 'shape=' argument must not be greater than %d"_err_en_US,
common::maxRank);
} else if (HasNegativeExtent(shape.value())) {
context_.messages().Say(
"'shape=' argument must not have a negative extent"_err_en_US);
} else {
int rank{GetRank(shape.value())};
std::size_t resultElements{TotalElementCount(shape.value())};
std::optional<std::vector<int>> dimOrder;
if (order) {
dimOrder = ValidateDimensionOrder(rank, *order);
}
std::vector<int> *dimOrderPtr{dimOrder ? &dimOrder.value() : nullptr};
if (order && !dimOrder) {
context_.messages().Say("Invalid 'order=' argument in RESHAPE"_err_en_US);
} else if (resultElements > source->size() && (!pad || pad->empty())) {
context_.messages().Say(
"Too few elements in 'source=' argument and 'pad=' "
"argument is not present or has null size"_err_en_US);
} else {
Constant<T> result{!source->empty() || !pad
? source->Reshape(std::move(shape.value()))
: pad->Reshape(std::move(shape.value()))};
ConstantSubscripts subscripts{result.lbounds()};
auto copied{result.CopyFrom(*source,
std::min(source->size(), resultElements), subscripts, dimOrderPtr)};
if (copied < resultElements) {
CHECK(pad);
copied += result.CopyFrom(
*pad, resultElements - copied, subscripts, dimOrderPtr);
}
CHECK(copied == resultElements);
return Expr<T>{std::move(result)};
}
}
// Invalid, prevent re-folding
return MakeInvalidIntrinsic(std::move(funcRef));
}
template <typename T>
Expr<T> FoldMINorMAX(
FoldingContext &context, FunctionRef<T> &&funcRef, Ordering order) {
std::vector<Constant<T> *> constantArgs;
// Call Folding on all arguments, even if some are not constant,
// to make operand promotion explicit.
for (auto &arg : funcRef.arguments()) {
if (auto *cst{Folder<T>{context}.Folding(arg)}) {
constantArgs.push_back(cst);
}
}
if (constantArgs.size() != funcRef.arguments().size())
return Expr<T>(std::move(funcRef));
CHECK(constantArgs.size() > 0);
Expr<T> result{std::move(*constantArgs[0])};
for (std::size_t i{1}; i < constantArgs.size(); ++i) {
Extremum<T> extremum{order, result, Expr<T>{std::move(*constantArgs[i])}};
result = FoldOperation(context, std::move(extremum));
}
return result;
}
// For AMAX0, AMIN0, AMAX1, AMIN1, DMAX1, DMIN1, MAX0, MIN0, MAX1, and MIN1
// a special care has to be taken to insert the conversion on the result
// of the MIN/MAX. This is made slightly more complex by the extension
// supported by f18 that arguments may have different kinds. This implies
// that the created MIN/MAX result type cannot be deduced from the standard but
// has to be deduced from the arguments.
// e.g. AMAX0(int8, int4) is rewritten to REAL(MAX(int8, INT(int4, 8)))).
template <typename T>
Expr<T> RewriteSpecificMINorMAX(
FoldingContext &context, FunctionRef<T> &&funcRef) {
ActualArguments &args{funcRef.arguments()};
auto &intrinsic{DEREF(std::get_if<SpecificIntrinsic>(&funcRef.proc().u))};
// Rewrite MAX1(args) to INT(MAX(args)) and fold. Same logic for MIN1.
// Find result type for max/min based on the arguments.
DynamicType resultType{args[0].value().GetType().value()};
auto *resultTypeArg{&args[0]};
for (auto j{args.size() - 1}; j > 0; --j) {
DynamicType type{args[j].value().GetType().value()};
if (type.category() == resultType.category()) {
if (type.kind() > resultType.kind()) {
resultTypeArg = &args[j];
resultType = type;
}
} else if (resultType.category() == TypeCategory::Integer) {
// Handle mixed real/integer arguments: all the previous arguments were
// integers and this one is real. The type of the MAX/MIN result will
// be the one of the real argument.
resultTypeArg = &args[j];
resultType = type;
}
}
intrinsic.name =
intrinsic.name.find("max") != std::string::npos ? "max"s : "min"s;
intrinsic.characteristics.value().functionResult.value().SetType(resultType);
auto insertConversion{[&](const auto &x) -> Expr<T> {
using TR = ResultType<decltype(x)>;
FunctionRef<TR> maxRef{std::move(funcRef.proc()), std::move(args)};
return Fold(context, ConvertToType<T>(AsCategoryExpr(std::move(maxRef))));
}};
if (auto *sx{UnwrapExpr<Expr<SomeReal>>(*resultTypeArg)}) {
return std::visit(insertConversion, sx->u);
}
auto &sx{DEREF(UnwrapExpr<Expr<SomeInteger>>(*resultTypeArg))};
return std::visit(insertConversion, sx.u);
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, FunctionRef<T> &&funcRef) {
ActualArguments &args{funcRef.arguments()};
for (std::optional<ActualArgument> &arg : args) {
if (auto *expr{UnwrapExpr<Expr<SomeType>>(arg)}) {
*expr = Fold(context, std::move(*expr));
}
}
if (auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)}) {
const std::string name{intrinsic->name};
if (name == "reshape") {
return Folder<T>{context}.Reshape(std::move(funcRef));
}
// TODO: other type independent transformationals
if constexpr (!std::is_same_v<T, SomeDerived>) {
return FoldIntrinsicFunction(context, std::move(funcRef));
}
}
return Expr<T>{std::move(funcRef)};
}
template <typename T>
Expr<T> FoldMerge(FoldingContext &context, FunctionRef<T> &&funcRef) {
return FoldElementalIntrinsic<T, T, T, LogicalResult>(context,
std::move(funcRef),
ScalarFunc<T, T, T, LogicalResult>(
[](const Scalar<T> &ifTrue, const Scalar<T> &ifFalse,
const Scalar<LogicalResult> &predicate) -> Scalar<T> {
return predicate.IsTrue() ? ifTrue : ifFalse;
}));
}
Expr<ImpliedDoIndex::Result> FoldOperation(FoldingContext &, ImpliedDoIndex &&);
// Array constructor folding
template <typename T> class ArrayConstructorFolder {
public:
explicit ArrayConstructorFolder(const FoldingContext &c) : context_{c} {}
Expr<T> FoldArray(ArrayConstructor<T> &&array) {
// Calls FoldArray(const ArrayConstructorValues<T> &) below
if (FoldArray(array)) {
auto n{static_cast<ConstantSubscript>(elements_.size())};
if constexpr (std::is_same_v<T, SomeDerived>) {
return Expr<T>{Constant<T>{array.GetType().GetDerivedTypeSpec(),
std::move(elements_), ConstantSubscripts{n}}};
} else if constexpr (T::category == TypeCategory::Character) {
auto length{Fold(context_, common::Clone(array.LEN()))};
if (std::optional<ConstantSubscript> lengthValue{ToInt64(length)}) {
return Expr<T>{Constant<T>{
*lengthValue, std::move(elements_), ConstantSubscripts{n}}};
}
} else {
return Expr<T>{
Constant<T>{std::move(elements_), ConstantSubscripts{n}}};
}
}
return Expr<T>{std::move(array)};
}
private:
bool FoldArray(const common::CopyableIndirection<Expr<T>> &expr) {
Expr<T> folded{Fold(context_, common::Clone(expr.value()))};
if (const auto *c{UnwrapConstantValue<T>(folded)}) {
// Copy elements in Fortran array element order
if (c->size() > 0) {
ConstantSubscripts index{c->lbounds()};
do {
elements_.emplace_back(c->At(index));
} while (c->IncrementSubscripts(index));
}
return true;
} else {
return false;
}
}
bool FoldArray(const ImpliedDo<T> &iDo) {
Expr<SubscriptInteger> lower{
Fold(context_, Expr<SubscriptInteger>{iDo.lower()})};
Expr<SubscriptInteger> upper{
Fold(context_, Expr<SubscriptInteger>{iDo.upper()})};
Expr<SubscriptInteger> stride{
Fold(context_, Expr<SubscriptInteger>{iDo.stride()})};
std::optional<ConstantSubscript> start{ToInt64(lower)}, end{ToInt64(upper)},
step{ToInt64(stride)};
if (start && end && step && *step != 0) {
bool result{true};
ConstantSubscript &j{context_.StartImpliedDo(iDo.name(), *start)};
if (*step > 0) {
for (; j <= *end; j += *step) {
result &= FoldArray(iDo.values());
}
} else {
for (; j >= *end; j += *step) {
result &= FoldArray(iDo.values());
}
}
context_.EndImpliedDo(iDo.name());
return result;
} else {
return false;
}
}
bool FoldArray(const ArrayConstructorValue<T> &x) {
return std::visit([&](const auto &y) { return FoldArray(y); }, x.u);
}
bool FoldArray(const ArrayConstructorValues<T> &xs) {
for (const auto &x : xs) {
if (!FoldArray(x)) {
return false;
}
}
return true;
}
FoldingContext context_;
std::vector<Scalar<T>> elements_;
};
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, ArrayConstructor<T> &&array) {
return ArrayConstructorFolder<T>{context}.FoldArray(std::move(array));
}
// Array operation elemental application: When all operands to an operation
// are constant arrays, array constructors without any implied DO loops,
// &/or expanded scalars, pull the operation "into" the array result by
// applying it in an elementwise fashion. For example, [A,1]+[B,2]
// is rewritten into [A+B,1+2] and then partially folded to [A+B,3].
// If possible, restructures an array expression into an array constructor
// that comprises a "flat" ArrayConstructorValues with no implied DO loops.
template <typename T>
bool ArrayConstructorIsFlat(const ArrayConstructorValues<T> &values) {
for (const ArrayConstructorValue<T> &x : values) {
if (!std::holds_alternative<Expr<T>>(x.u)) {
return false;
}
}
return true;
}
template <typename T>
std::optional<Expr<T>> AsFlatArrayConstructor(const Expr<T> &expr) {
if (const auto *c{UnwrapConstantValue<T>(expr)}) {
ArrayConstructor<T> result{expr};
if (c->size() > 0) {
ConstantSubscripts at{c->lbounds()};
do {
result.Push(Expr<T>{Constant<T>{c->At(at)}});
} while (c->IncrementSubscripts(at));
}
return std::make_optional<Expr<T>>(std::move(result));
} else if (const auto *a{UnwrapExpr<ArrayConstructor<T>>(expr)}) {
if (ArrayConstructorIsFlat(*a)) {
return std::make_optional<Expr<T>>(expr);
}
} else if (const auto *p{UnwrapExpr<Parentheses<T>>(expr)}) {
return AsFlatArrayConstructor(Expr<T>{p->left()});
}
return std::nullopt;
}
template <TypeCategory CAT>
std::enable_if_t<CAT != TypeCategory::Derived,
std::optional<Expr<SomeKind<CAT>>>>
AsFlatArrayConstructor(const Expr<SomeKind<CAT>> &expr) {
return std::visit(
[&](const auto &kindExpr) -> std::optional<Expr<SomeKind<CAT>>> {
if (auto flattened{AsFlatArrayConstructor(kindExpr)}) {
return Expr<SomeKind<CAT>>{std::move(*flattened)};
} else {
return std::nullopt;
}
},
expr.u);
}
// FromArrayConstructor is a subroutine for MapOperation() below.
// Given a flat ArrayConstructor<T> and a shape, it wraps the array
// into an Expr<T>, folds it, and returns the resulting wrapped
// array constructor or constant array value.
template <typename T>
Expr<T> FromArrayConstructor(FoldingContext &context,
ArrayConstructor<T> &&values, std::optional<ConstantSubscripts> &&shape) {
Expr<T> result{Fold(context, Expr<T>{std::move(values)})};
if (shape) {
if (auto *constant{UnwrapConstantValue<T>(result)}) {
return Expr<T>{constant->Reshape(std::move(*shape))};
}
}
return result;
}
// MapOperation is a utility for various specializations of ApplyElementwise()
// that follow. Given one or two flat ArrayConstructor<OPERAND> (wrapped in an
// Expr<OPERAND>) for some specific operand type(s), apply a given function f
// to each of their corresponding elements to produce a flat
// ArrayConstructor<RESULT> (wrapped in an Expr<RESULT>).
// Preserves shape.
// Unary case
template <typename RESULT, typename OPERAND>
Expr<RESULT> MapOperation(FoldingContext &context,
std::function<Expr<RESULT>(Expr<OPERAND> &&)> &&f, const Shape &shape,
Expr<OPERAND> &&values) {
ArrayConstructor<RESULT> result{values};
if constexpr (common::HasMember<OPERAND, AllIntrinsicCategoryTypes>) {
std::visit(
[&](auto &&kindExpr) {
using kindType = ResultType<decltype(kindExpr)>;
auto &aConst{std::get<ArrayConstructor<kindType>>(kindExpr.u)};
for (auto &acValue : aConst) {
auto &scalar{std::get<Expr<kindType>>(acValue.u)};
result.Push(Fold(context, f(Expr<OPERAND>{std::move(scalar)})));
}
},
std::move(values.u));
} else {
auto &aConst{std::get<ArrayConstructor<OPERAND>>(values.u)};
for (auto &acValue : aConst) {
auto &scalar{std::get<Expr<OPERAND>>(acValue.u)};
result.Push(Fold(context, f(std::move(scalar))));
}
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(context, shape));
}
// array * array case
template <typename RESULT, typename LEFT, typename RIGHT>
Expr<RESULT> MapOperation(FoldingContext &context,
std::function<Expr<RESULT>(Expr<LEFT> &&, Expr<RIGHT> &&)> &&f,
const Shape &shape, Expr<LEFT> &&leftValues, Expr<RIGHT> &&rightValues) {
ArrayConstructor<RESULT> result{leftValues};
auto &leftArrConst{std::get<ArrayConstructor<LEFT>>(leftValues.u)};
if constexpr (common::HasMember<RIGHT, AllIntrinsicCategoryTypes>) {
std::visit(
[&](auto &&kindExpr) {
using kindType = ResultType<decltype(kindExpr)>;
auto &rightArrConst{std::get<ArrayConstructor<kindType>>(kindExpr.u)};
auto rightIter{rightArrConst.begin()};
for (auto &leftValue : leftArrConst) {
CHECK(rightIter != rightArrConst.end());
auto &leftScalar{std::get<Expr<LEFT>>(leftValue.u)};
auto &rightScalar{std::get<Expr<kindType>>(rightIter->u)};
result.Push(Fold(context,
f(std::move(leftScalar), Expr<RIGHT>{std::move(rightScalar)})));
++rightIter;
}
},
std::move(rightValues.u));
} else {
auto &rightArrConst{std::get<ArrayConstructor<RIGHT>>(rightValues.u)};
auto rightIter{rightArrConst.begin()};
for (auto &leftValue : leftArrConst) {
CHECK(rightIter != rightArrConst.end());
auto &leftScalar{std::get<Expr<LEFT>>(leftValue.u)};
auto &rightScalar{std::get<Expr<RIGHT>>(rightIter->u)};
result.Push(
Fold(context, f(std::move(leftScalar), std::move(rightScalar))));
++rightIter;
}
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(context, shape));
}
// array * scalar case
template <typename RESULT, typename LEFT, typename RIGHT>
Expr<RESULT> MapOperation(FoldingContext &context,
std::function<Expr<RESULT>(Expr<LEFT> &&, Expr<RIGHT> &&)> &&f,
const Shape &shape, Expr<LEFT> &&leftValues,
const Expr<RIGHT> &rightScalar) {
ArrayConstructor<RESULT> result{leftValues};
auto &leftArrConst{std::get<ArrayConstructor<LEFT>>(leftValues.u)};
for (auto &leftValue : leftArrConst) {
auto &leftScalar{std::get<Expr<LEFT>>(leftValue.u)};
result.Push(
Fold(context, f(std::move(leftScalar), Expr<RIGHT>{rightScalar})));
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(context, shape));
}
// scalar * array case
template <typename RESULT, typename LEFT, typename RIGHT>
Expr<RESULT> MapOperation(FoldingContext &context,
std::function<Expr<RESULT>(Expr<LEFT> &&, Expr<RIGHT> &&)> &&f,
const Shape &shape, const Expr<LEFT> &leftScalar,
Expr<RIGHT> &&rightValues) {
ArrayConstructor<RESULT> result{leftScalar};
if constexpr (common::HasMember<RIGHT, AllIntrinsicCategoryTypes>) {
std::visit(
[&](auto &&kindExpr) {
using kindType = ResultType<decltype(kindExpr)>;
auto &rightArrConst{std::get<ArrayConstructor<kindType>>(kindExpr.u)};
for (auto &rightValue : rightArrConst) {
auto &rightScalar{std::get<Expr<kindType>>(rightValue.u)};
result.Push(Fold(context,
f(Expr<LEFT>{leftScalar},
Expr<RIGHT>{std::move(rightScalar)})));
}
},
std::move(rightValues.u));
} else {
auto &rightArrConst{std::get<ArrayConstructor<RIGHT>>(rightValues.u)};
for (auto &rightValue : rightArrConst) {
auto &rightScalar{std::get<Expr<RIGHT>>(rightValue.u)};
result.Push(
Fold(context, f(Expr<LEFT>{leftScalar}, std::move(rightScalar))));
}
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(context, shape));
}
// ApplyElementwise() recursively folds the operand expression(s) of an
// operation, then attempts to apply the operation to the (corresponding)
// scalar element(s) of those operands. Returns std::nullopt for scalars
// or unlinearizable operands.
template <typename DERIVED, typename RESULT, typename OPERAND>
auto ApplyElementwise(FoldingContext &context,
Operation<DERIVED, RESULT, OPERAND> &operation,
std::function<Expr<RESULT>(Expr<OPERAND> &&)> &&f)
-> std::optional<Expr<RESULT>> {
auto &expr{operation.left()};
expr = Fold(context, std::move(expr));
if (expr.Rank() > 0) {
if (std::optional<Shape> shape{GetShape(context, expr)}) {
if (auto values{AsFlatArrayConstructor(expr)}) {
return MapOperation(context, std::move(f), *shape, std::move(*values));
}
}
}
return std::nullopt;
}
template <typename DERIVED, typename RESULT, typename OPERAND>
auto ApplyElementwise(
FoldingContext &context, Operation<DERIVED, RESULT, OPERAND> &operation)
-> std::optional<Expr<RESULT>> {
return ApplyElementwise(context, operation,
std::function<Expr<RESULT>(Expr<OPERAND> &&)>{
[](Expr<OPERAND> &&operand) {
return Expr<RESULT>{DERIVED{std::move(operand)}};
}});
}
template <typename DERIVED, typename RESULT, typename LEFT, typename RIGHT>
auto ApplyElementwise(FoldingContext &context,
Operation<DERIVED, RESULT, LEFT, RIGHT> &operation,
std::function<Expr<RESULT>(Expr<LEFT> &&, Expr<RIGHT> &&)> &&f)
-> std::optional<Expr<RESULT>> {
auto &leftExpr{operation.left()};
leftExpr = Fold(context, std::move(leftExpr));
auto &rightExpr{operation.right()};
rightExpr = Fold(context, std::move(rightExpr));
if (leftExpr.Rank() > 0) {
if (std::optional<Shape> leftShape{GetShape(context, leftExpr)}) {
if (auto left{AsFlatArrayConstructor(leftExpr)}) {
if (rightExpr.Rank() > 0) {
if (std::optional<Shape> rightShape{GetShape(context, rightExpr)}) {
if (auto right{AsFlatArrayConstructor(rightExpr)}) {
if (CheckConformance(
context.messages(), *leftShape, *rightShape)) {
return MapOperation(context, std::move(f), *leftShape,
std::move(*left), std::move(*right));
} else {
return std::nullopt;
}
return MapOperation(context, std::move(f), *leftShape,
std::move(*left), std::move(*right));
}
}
} else if (IsExpandableScalar(rightExpr)) {
return MapOperation(
context, std::move(f), *leftShape, std::move(*left), rightExpr);
}
}
}
} else if (rightExpr.Rank() > 0 && IsExpandableScalar(leftExpr)) {
if (std::optional<Shape> shape{GetShape(context, rightExpr)}) {
if (auto right{AsFlatArrayConstructor(rightExpr)}) {
return MapOperation(
context, std::move(f), *shape, leftExpr, std::move(*right));
}
}
}
return std::nullopt;
}
template <typename DERIVED, typename RESULT, typename LEFT, typename RIGHT>
auto ApplyElementwise(
FoldingContext &context, Operation<DERIVED, RESULT, LEFT, RIGHT> &operation)
-> std::optional<Expr<RESULT>> {
return ApplyElementwise(context, operation,
std::function<Expr<RESULT>(Expr<LEFT> &&, Expr<RIGHT> &&)>{
[](Expr<LEFT> &&left, Expr<RIGHT> &&right) {
return Expr<RESULT>{DERIVED{std::move(left), std::move(right)}};
}});
}
// Unary operations
template <typename TO, typename FROM>
common::IfNoLvalue<std::optional<TO>, FROM> ConvertString(FROM &&s) {
if constexpr (std::is_same_v<TO, FROM>) {
return std::make_optional<TO>(std::move(s));
} else {
// Fortran character conversion is well defined between distinct kinds
// only when the actual characters are valid 7-bit ASCII.
TO str;
for (auto iter{s.cbegin()}; iter != s.cend(); ++iter) {
if (static_cast<std::uint64_t>(*iter) > 127) {
return std::nullopt;
}
str.push_back(*iter);
}
return std::make_optional<TO>(std::move(str));
}
}
template <typename TO, TypeCategory FROMCAT>
Expr<TO> FoldOperation(
FoldingContext &context, Convert<TO, FROMCAT> &&convert) {
if (auto array{ApplyElementwise(context, convert)}) {
return *array;
}
struct {
FoldingContext &context;
Convert<TO, FROMCAT> &convert;
} msvcWorkaround{context, convert};
return std::visit(
[&msvcWorkaround](auto &kindExpr) -> Expr<TO> {
using Operand = ResultType<decltype(kindExpr)>;
// This variable is a workaround for msvc which emits an error when
// using the FROMCAT template parameter below.
TypeCategory constexpr FromCat{FROMCAT};
static_assert(FromCat == Operand::category);
auto &convert{msvcWorkaround.convert};
char buffer[64];
if (auto value{GetScalarConstantValue<Operand>(kindExpr)}) {
FoldingContext &ctx{msvcWorkaround.context};
if constexpr (TO::category == TypeCategory::Integer) {
if constexpr (FromCat == TypeCategory::Integer) {
auto converted{Scalar<TO>::ConvertSigned(*value)};
if (converted.overflow) {
ctx.messages().Say(
"INTEGER(%d) to INTEGER(%d) conversion overflowed"_en_US,
Operand::kind, TO::kind);
}
return ScalarConstantToExpr(std::move(converted.value));
} else if constexpr (FromCat == TypeCategory::Real) {
auto converted{value->template ToInteger<Scalar<TO>>()};
if (converted.flags.test(RealFlag::InvalidArgument)) {
ctx.messages().Say(
"REAL(%d) to INTEGER(%d) conversion: invalid argument"_en_US,
Operand::kind, TO::kind);
} else if (converted.flags.test(RealFlag::Overflow)) {
ctx.messages().Say(
"REAL(%d) to INTEGER(%d) conversion overflowed"_en_US,
Operand::kind, TO::kind);
}
return ScalarConstantToExpr(std::move(converted.value));
}
} else if constexpr (TO::category == TypeCategory::Real) {
if constexpr (FromCat == TypeCategory::Integer) {
auto converted{Scalar<TO>::FromInteger(*value)};
if (!converted.flags.empty()) {
std::snprintf(buffer, sizeof buffer,
"INTEGER(%d) to REAL(%d) conversion", Operand::kind,
TO::kind);
RealFlagWarnings(ctx, converted.flags, buffer);
}
return ScalarConstantToExpr(std::move(converted.value));
} else if constexpr (FromCat == TypeCategory::Real) {
auto converted{Scalar<TO>::Convert(*value)};
if (!converted.flags.empty()) {
std::snprintf(buffer, sizeof buffer,
"REAL(%d) to REAL(%d) conversion", Operand::kind, TO::kind);
RealFlagWarnings(ctx, converted.flags, buffer);
}
if (ctx.flushSubnormalsToZero()) {
converted.value = converted.value.FlushSubnormalToZero();
}
return ScalarConstantToExpr(std::move(converted.value));
}
} else if constexpr (TO::category == TypeCategory::Complex) {
if constexpr (FromCat == TypeCategory::Complex) {
return FoldOperation(ctx,
ComplexConstructor<TO::kind>{
AsExpr(Convert<typename TO::Part>{AsCategoryExpr(
Constant<typename Operand::Part>{value->REAL()})}),
AsExpr(Convert<typename TO::Part>{AsCategoryExpr(
Constant<typename Operand::Part>{value->AIMAG()})})});
}
} else if constexpr (TO::category == TypeCategory::Character &&
FromCat == TypeCategory::Character) {
if (auto converted{ConvertString<Scalar<TO>>(std::move(*value))}) {
return ScalarConstantToExpr(std::move(*converted));
}
} else if constexpr (TO::category == TypeCategory::Logical &&
FromCat == TypeCategory::Logical) {
return Expr<TO>{value->IsTrue()};
}
} else if constexpr (TO::category == FromCat &&
FromCat != TypeCategory::Character) {
// Conversion of non-constant in same type category
if constexpr (std::is_same_v<Operand, TO>) {
return std::move(kindExpr); // remove needless conversion
} else if constexpr (TO::category == TypeCategory::Logical ||
TO::category == TypeCategory::Integer) {
if (auto *innerConv{
std::get_if<Convert<Operand, TO::category>>(&kindExpr.u)}) {
// Conversion of conversion of same category & kind
if (auto *x{std::get_if<Expr<TO>>(&innerConv->left().u)}) {
if constexpr (TO::category == TypeCategory::Logical ||
TO::kind <= Operand::kind) {
return std::move(*x); // no-op Logical or Integer
// widening/narrowing conversion pair
} else if constexpr (std::is_same_v<TO,
DescriptorInquiry::Result>) {
if (std::holds_alternative<DescriptorInquiry>(x->u) ||
std::holds_alternative<TypeParamInquiry>(x->u)) {
// int(int(size(...),kind=k),kind=8) -> size(...)
return std::move(*x);
}
}
}
}
}
}
return Expr<TO>{std::move(convert)};
},
convert.left().u);
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Parentheses<T> &&x) {
auto &operand{x.left()};
operand = Fold(context, std::move(operand));
if (auto value{GetScalarConstantValue<T>(operand)}) {
// Preserve parentheses, even around constants.
return Expr<T>{Parentheses<T>{Expr<T>{Constant<T>{*value}}}};
} else if (std::holds_alternative<Parentheses<T>>(operand.u)) {
// ((x)) -> (x)
return std::move(operand);
} else {
return Expr<T>{Parentheses<T>{std::move(operand)}};
}
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Negate<T> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
auto &operand{x.left()};
if (auto *nn{std::get_if<Negate<T>>(&x.left().u)}) {
return std::move(nn->left()); // -(-x) -> x
} else if (auto value{GetScalarConstantValue<T>(operand)}) {
if constexpr (T::category == TypeCategory::Integer) {
auto negated{value->Negate()};
if (negated.overflow) {
context.messages().Say(
"INTEGER(%d) negation overflowed"_en_US, T::kind);
}
return Expr<T>{Constant<T>{std::move(negated.value)}};
} else {
// REAL & COMPLEX negation: no exceptions possible
return Expr<T>{Constant<T>{value->Negate()}};
}
}
return Expr<T>{std::move(x)};
}
// Binary (dyadic) operations
template <typename LEFT, typename RIGHT>
std::optional<std::pair<Scalar<LEFT>, Scalar<RIGHT>>> OperandsAreConstants(
const Expr<LEFT> &x, const Expr<RIGHT> &y) {
if (auto xvalue{GetScalarConstantValue<LEFT>(x)}) {
if (auto yvalue{GetScalarConstantValue<RIGHT>(y)}) {
return {std::make_pair(*xvalue, *yvalue)};
}
}
return std::nullopt;
}
template <typename DERIVED, typename RESULT, typename LEFT, typename RIGHT>
std::optional<std::pair<Scalar<LEFT>, Scalar<RIGHT>>> OperandsAreConstants(
const Operation<DERIVED, RESULT, LEFT, RIGHT> &operation) {
return OperandsAreConstants(operation.left(), operation.right());
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Add<T> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
if (auto folded{OperandsAreConstants(x)}) {
if constexpr (T::category == TypeCategory::Integer) {
auto sum{folded->first.AddSigned(folded->second)};
if (sum.overflow) {
context.messages().Say(
"INTEGER(%d) addition overflowed"_en_US, T::kind);
}
return Expr<T>{Constant<T>{sum.value}};
} else {
auto sum{folded->first.Add(folded->second, context.rounding())};
RealFlagWarnings(context, sum.flags, "addition");
if (context.flushSubnormalsToZero()) {
sum.value = sum.value.FlushSubnormalToZero();
}
return Expr<T>{Constant<T>{sum.value}};
}
}
return Expr<T>{std::move(x)};
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Subtract<T> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
if (auto folded{OperandsAreConstants(x)}) {
if constexpr (T::category == TypeCategory::Integer) {
auto difference{folded->first.SubtractSigned(folded->second)};
if (difference.overflow) {
context.messages().Say(
"INTEGER(%d) subtraction overflowed"_en_US, T::kind);
}
return Expr<T>{Constant<T>{difference.value}};
} else {
auto difference{
folded->first.Subtract(folded->second, context.rounding())};
RealFlagWarnings(context, difference.flags, "subtraction");
if (context.flushSubnormalsToZero()) {
difference.value = difference.value.FlushSubnormalToZero();
}
return Expr<T>{Constant<T>{difference.value}};
}
}
return Expr<T>{std::move(x)};
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Multiply<T> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
if (auto folded{OperandsAreConstants(x)}) {
if constexpr (T::category == TypeCategory::Integer) {
auto product{folded->first.MultiplySigned(folded->second)};
if (product.SignedMultiplicationOverflowed()) {
context.messages().Say(
"INTEGER(%d) multiplication overflowed"_en_US, T::kind);
}
return Expr<T>{Constant<T>{product.lower}};
} else {
auto product{folded->first.Multiply(folded->second, context.rounding())};
RealFlagWarnings(context, product.flags, "multiplication");
if (context.flushSubnormalsToZero()) {
product.value = product.value.FlushSubnormalToZero();
}
return Expr<T>{Constant<T>{product.value}};
}
} else if constexpr (T::category == TypeCategory::Integer) {
if (auto c{GetScalarConstantValue<T>(x.right())}) {
x.right() = std::move(x.left());
x.left() = Expr<T>{std::move(*c)};
}
if (auto c{GetScalarConstantValue<T>(x.left())}) {
if (c->IsZero()) {
return std::move(x.left());
} else if (c->CompareSigned(Scalar<T>{1}) == Ordering::Equal) {
return std::move(x.right());
} else if (c->CompareSigned(Scalar<T>{-1}) == Ordering::Equal) {
return Expr<T>{Negate<T>{std::move(x.right())}};
}
}
}
return Expr<T>{std::move(x)};
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Divide<T> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
if (auto folded{OperandsAreConstants(x)}) {
if constexpr (T::category == TypeCategory::Integer) {
auto quotAndRem{folded->first.DivideSigned(folded->second)};
if (quotAndRem.divisionByZero) {
context.messages().Say("INTEGER(%d) division by zero"_en_US, T::kind);
return Expr<T>{std::move(x)};
}
if (quotAndRem.overflow) {
context.messages().Say(
"INTEGER(%d) division overflowed"_en_US, T::kind);
}
return Expr<T>{Constant<T>{quotAndRem.quotient}};
} else {
auto quotient{folded->first.Divide(folded->second, context.rounding())};
RealFlagWarnings(context, quotient.flags, "division");
if (context.flushSubnormalsToZero()) {
quotient.value = quotient.value.FlushSubnormalToZero();
}
return Expr<T>{Constant<T>{quotient.value}};
}
}
return Expr<T>{std::move(x)};
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Power<T> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
if (auto folded{OperandsAreConstants(x)}) {
if constexpr (T::category == TypeCategory::Integer) {
auto power{folded->first.Power(folded->second)};
if (power.divisionByZero) {
context.messages().Say(
"INTEGER(%d) zero to negative power"_en_US, T::kind);
} else if (power.overflow) {
context.messages().Say("INTEGER(%d) power overflowed"_en_US, T::kind);
} else if (power.zeroToZero) {
context.messages().Say(
"INTEGER(%d) 0**0 is not defined"_en_US, T::kind);
}
return Expr<T>{Constant<T>{power.power}};
} else {
if (auto callable{GetHostRuntimeWrapper<T, T, T>("pow")}) {
return Expr<T>{
Constant<T>{(*callable)(context, folded->first, folded->second)}};
} else {
context.messages().Say(
"Power for %s cannot be folded on host"_en_US, T{}.AsFortran());
}
}
}
return Expr<T>{std::move(x)};
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, RealToIntPower<T> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
return std::visit(
[&](auto &y) -> Expr<T> {
if (auto folded{OperandsAreConstants(x.left(), y)}) {
auto power{evaluate::IntPower(folded->first, folded->second)};
RealFlagWarnings(context, power.flags, "power with INTEGER exponent");
if (context.flushSubnormalsToZero()) {
power.value = power.value.FlushSubnormalToZero();
}
return Expr<T>{Constant<T>{power.value}};
} else {
return Expr<T>{std::move(x)};
}
},
x.right().u);
}
template <typename T>
Expr<T> FoldOperation(FoldingContext &context, Extremum<T> &&x) {
if (auto array{ApplyElementwise(context, x,
std::function<Expr<T>(Expr<T> &&, Expr<T> &&)>{[=](Expr<T> &&l,
Expr<T> &&r) {
return Expr<T>{Extremum<T>{x.ordering, std::move(l), std::move(r)}};
}})}) {
return *array;
}
if (auto folded{OperandsAreConstants(x)}) {
if constexpr (T::category == TypeCategory::Integer) {
if (folded->first.CompareSigned(folded->second) == x.ordering) {
return Expr<T>{Constant<T>{folded->first}};
}
} else if constexpr (T::category == TypeCategory::Real) {
if (folded->first.IsNotANumber() ||
(folded->first.Compare(folded->second) == Relation::Less) ==
(x.ordering == Ordering::Less)) {
return Expr<T>{Constant<T>{folded->first}};
}
} else {
static_assert(T::category == TypeCategory::Character);
// Result of MIN and MAX on character has the length of
// the longest argument.
auto maxLen{std::max(folded->first.length(), folded->second.length())};
bool isFirst{x.ordering == Compare(folded->first, folded->second)};
auto res{isFirst ? std::move(folded->first) : std::move(folded->second)};
res = res.length() == maxLen
? std::move(res)
: CharacterUtils<T::kind>::Resize(res, maxLen);
return Expr<T>{Constant<T>{std::move(res)}};
}
return Expr<T>{Constant<T>{folded->second}};
}
return Expr<T>{std::move(x)};
}
template <int KIND>
Expr<Type<TypeCategory::Real, KIND>> ToReal(
FoldingContext &context, Expr<SomeType> &&expr) {
using Result = Type<TypeCategory::Real, KIND>;
std::optional<Expr<Result>> result;
std::visit(
[&](auto &&x) {
using From = std::decay_t<decltype(x)>;
if constexpr (std::is_same_v<From, BOZLiteralConstant>) {
// Move the bits without any integer->real conversion
From original{x};
result = ConvertToType<Result>(std::move(x));
const auto *constant{UnwrapExpr<Constant<Result>>(*result)};
CHECK(constant);
Scalar<Result> real{constant->GetScalarValue().value()};
From converted{From::ConvertUnsigned(real.RawBits()).value};
if (original != converted) { // C1601
context.messages().Say(
"Nonzero bits truncated from BOZ literal constant in REAL intrinsic"_en_US);
}
} else if constexpr (IsNumericCategoryExpr<From>()) {
result = Fold(context, ConvertToType<Result>(std::move(x)));
} else {
common::die("ToReal: bad argument expression");
}
},
std::move(expr.u));
return result.value();
}
template <typename T>
Expr<T> ExpressionBase<T>::Rewrite(FoldingContext &context, Expr<T> &&expr) {
return std::visit(
[&](auto &&x) -> Expr<T> {
if constexpr (IsSpecificIntrinsicType<T>) {
return FoldOperation(context, std::move(x));
} else if constexpr (std::is_same_v<T, SomeDerived>) {
return FoldOperation(context, std::move(x));
} else if constexpr (common::HasMember<decltype(x),
TypelessExpression>) {
return std::move(expr);
} else {
return Expr<T>{Fold(context, std::move(x))};
}
},
std::move(expr.u));
}
FOR_EACH_TYPE_AND_KIND(extern template class ExpressionBase, )
} // namespace Fortran::evaluate
#endif // FORTRAN_EVALUATE_FOLD_IMPLEMENTATION_H_
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