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llvm/flang/lib/evaluate/fold.cc
peter klausler 146e13ce22 [flang] Fold array operations 
Original-commit: flang-compiler/f18@e6c86ecfd1
Reviewed-on: https://github.com/flang-compiler/f18/pull/420
2019-04-18 14:48:05 -07:00

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// Copyright (c) 2018-2019, NVIDIA CORPORATION. All rights reserved.
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
#include "fold.h"
#include "common.h"
#include "constant.h"
#include "expression.h"
#include "host.h"
#include "int-power.h"
#include "intrinsics-library-templates.h"
#include "shape.h"
#include "tools.h"
#include "traversal.h"
#include "type.h"
#include "../common/indirection.h"
#include "../common/template.h"
#include "../common/unwrap.h"
#include "../parser/message.h"
#include "../semantics/scope.h"
#include "../semantics/symbol.h"
#include <cmath>
#include <complex>
#include <cstdio>
#include <optional>
#include <type_traits>
#include <variant>
namespace Fortran::evaluate {
// no-op base case
template<typename A>
common::IfNoLvalue<Expr<ResultType<A>>, A> FoldOperation(
FoldingContext &, A &&x) {
return Expr<ResultType<A>>{std::move(x)};
}
// Forward declarations of overloads, template instantiations, and template
// specializations of FoldOperation() to enable mutual recursion between them.
BaseObject FoldOperation(FoldingContext &, BaseObject &&);
Component FoldOperation(FoldingContext &, Component &&);
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<int KIND>
Expr<Type<TypeCategory::Integer, KIND>> FoldOperation(
FoldingContext &context, FunctionRef<Type<TypeCategory::Integer, KIND>> &&);
template<int KIND>
Expr<Type<TypeCategory::Real, KIND>> FoldOperation(
FoldingContext &context, FunctionRef<Type<TypeCategory::Real, KIND>> &&);
template<int KIND>
Expr<Type<TypeCategory::Complex, KIND>> FoldOperation(
FoldingContext &context, FunctionRef<Type<TypeCategory::Complex, KIND>> &&);
// TODO: Character intrinsic function folding
template<int KIND>
Expr<Type<TypeCategory::Logical, KIND>> FoldOperation(
FoldingContext &context, FunctionRef<Type<TypeCategory::Logical, KIND>> &&);
template<typename T> Expr<T> FoldOperation(FoldingContext &, Designator<T> &&);
template<int KIND>
Expr<Type<TypeCategory::Integer, KIND>> FoldOperation(
FoldingContext &, TypeParamInquiry<KIND> &&);
template<typename T>
Expr<T> FoldOperation(FoldingContext &, ArrayConstructor<T> &&);
Expr<SomeDerived> FoldOperation(FoldingContext &, StructureConstructor &&);
// Overloads, instantiations, and specializations of FoldOperation().
BaseObject FoldOperation(FoldingContext &, BaseObject &&object) {
return std::move(object);
}
Component FoldOperation(FoldingContext &context, Component &&component) {
return {FoldOperation(context, std::move(component.base())),
component.GetLastSymbol()};
}
Triplet FoldOperation(FoldingContext &context, Triplet &&triplet) {
return {Fold(context, triplet.lower()), Fold(context, triplet.upper()),
Fold(context, common::Clone(triplet.stride()))};
}
Subscript FoldOperation(FoldingContext &context, Subscript &&subscript) {
return std::visit(
common::visitors{
[&](IndirectSubscriptIntegerExpr &&expr) {
expr.value() = Fold(context, std::move(expr.value()));
return Subscript(std::move(expr));
},
[&](Triplet &&triplet) {
return Subscript(FoldOperation(context, std::move(triplet)));
},
},
std::move(subscript.u));
}
ArrayRef FoldOperation(FoldingContext &context, ArrayRef &&arrayRef) {
for (Subscript &subscript : arrayRef.subscript()) {
subscript = FoldOperation(context, std::move(subscript));
}
return std::visit(
common::visitors{
[&](const Symbol *symbol) {
return ArrayRef{*symbol, std::move(arrayRef.subscript())};
},
[&](Component &&component) {
return ArrayRef{FoldOperation(context, std::move(component)),
std::move(arrayRef.subscript())};
},
},
std::move(arrayRef.base()));
}
CoarrayRef FoldOperation(FoldingContext &context, CoarrayRef &&coarrayRef) {
std::vector<Subscript> subscript;
for (Subscript x : coarrayRef.subscript()) {
subscript.emplace_back(FoldOperation(context, std::move(x)));
}
std::vector<Expr<SubscriptInteger>> cosubscript;
for (Expr<SubscriptInteger> x : coarrayRef.cosubscript()) {
cosubscript.emplace_back(Fold(context, std::move(x)));
}
CoarrayRef folded{std::move(coarrayRef.base()), std::move(subscript),
std::move(cosubscript)};
if (std::optional<Expr<SomeInteger>> stat{coarrayRef.stat()}) {
folded.set_stat(Fold(context, std::move(*stat)));
}
if (std::optional<Expr<SomeInteger>> team{coarrayRef.team()}) {
folded.set_team(
Fold(context, std::move(*team)), coarrayRef.teamIsTeamNumber());
}
return folded;
}
DataRef FoldOperation(FoldingContext &context, DataRef &&dataRef) {
return std::visit(
common::visitors{
[&](const Symbol *symbol) { return DataRef{*symbol}; },
[&](auto &&x) {
return DataRef{FoldOperation(context, std::move(x))};
},
},
std::move(dataRef.u));
}
Substring FoldOperation(FoldingContext &context, Substring &&substring) {
std::optional<Expr<SubscriptInteger>> lower{Fold(context, substring.lower())};
std::optional<Expr<SubscriptInteger>> upper{Fold(context, substring.upper())};
if (const DataRef * dataRef{substring.GetParentIf<DataRef>()}) {
return Substring{FoldOperation(context, DataRef{*dataRef}),
std::move(lower), std::move(upper)};
} else {
auto p{*substring.GetParentIf<StaticDataObject::Pointer>()};
return Substring{std::move(p), std::move(lower), std::move(upper)};
}
}
ComplexPart FoldOperation(FoldingContext &context, ComplexPart &&complexPart) {
DataRef complex{complexPart.complex()};
return ComplexPart{
FoldOperation(context, std::move(complex)), complexPart.part()};
}
// 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>
static inline Expr<TR> FoldElementalIntrinsicHelper(FoldingContext &context,
FunctionRef<TR> &&funcRef, WrapperType<TR, TA...> func,
std::index_sequence<I...>) {
static_assert(
(... && IsSpecificIntrinsicType<TA>)); // TODO derived types for MERGE?
static_assert(sizeof...(TA) > 0);
std::tuple<const Constant<TA> *...> args{
UnwrapExpr<Constant<TA>>(*funcRef.arguments()[I].value().GetExpr())...};
if ((... && (std::get<I>(args) != nullptr))) {
// Compute the shape of the result based on shapes of arguments
ConstantSubscripts shape;
int rank{0};
const ConstantSubscripts *shapes[sizeof...(TA)]{
&std::get<I>(args)->shape()...};
const int ranks[sizeof...(TA)]{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 == static_cast<int>(shape.size()));
// Compute all the scalar values of the results
std::vector<Scalar<TR>> results;
if (TotalElementCount(shape) > 0) {
ConstantSubscripts index{InitialSubscripts(rank)};
do {
if constexpr (std::is_same_v<WrapperType<TR, TA...>,
ScalarFuncWithContext<TR, TA...>>) {
results.emplace_back(func(context,
(ranks[I] ? std::get<I>(args)->At(index)
: **std::get<I>(args))...));
} else if constexpr (std::is_same_v<WrapperType<TR, TA...>,
ScalarFunc<TR, TA...>>) {
results.emplace_back(func((ranks[I] ? std::get<I>(args)->At(index)
: **std::get<I>(args))...));
}
} while (IncrementSubscripts(index, shape));
}
// Build and return constant result
if constexpr (TR::category == TypeCategory::Character) {
std::int64_t len{
static_cast<std::int64_t>(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>
static 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>
static 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...>{});
}
template<typename T>
static Expr<T> *UnwrapArgument(std::optional<ActualArgument> &arg) {
if (arg.has_value()) {
if (Expr<SomeType> * expr{arg->GetExpr()}) {
return UnwrapExpr<Expr<T>>(*expr);
}
}
return nullptr;
}
static BOZLiteralConstant *UnwrapBozArgument(
std::optional<ActualArgument> &arg) {
if (auto *expr{UnwrapArgument<SomeType>(arg)}) {
return std::get_if<BOZLiteralConstant>(&expr->u);
} else {
return nullptr;
}
}
template<int KIND>
Expr<Type<TypeCategory::Integer, KIND>> FoldOperation(FoldingContext &context,
FunctionRef<Type<TypeCategory::Integer, KIND>> &&funcRef) {
using T = Type<TypeCategory::Integer, KIND>;
ActualArguments &args{funcRef.arguments()};
for (std::optional<ActualArgument> &arg : args) {
if (auto *expr{UnwrapArgument<SomeType>(arg)}) {
*expr = FoldOperation(context, std::move(*expr));
}
}
if (auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)}) {
const std::string name{intrinsic->name};
if (name == "abs") {
return FoldElementalIntrinsic<T, T>(context, std::move(funcRef),
ScalarFunc<T, T>([&context](const Scalar<T> &i) -> Scalar<T> {
typename Scalar<T>::ValueWithOverflow j{i.ABS()};
if (j.overflow) {
context.messages().Say(
"abs(integer(kind=%d)) folding overflowed"_en_US, KIND);
}
return j.value;
}));
} else if (name == "dim") {
return FoldElementalIntrinsic<T, T, T>(
context, std::move(funcRef), &Scalar<T>::DIM);
} else if (name == "dshiftl" || name == "dshiftr") {
// convert boz
for (int i{0}; i <= 1; ++i) {
if (auto *x{UnwrapBozArgument(args[i])}) {
*args[i] =
AsGenericExpr(Fold(context, ConvertToType<T>(std::move(*x))));
}
}
// Third argument can be of any kind. However, it must be smaller or equal
// than BIT_SIZE. It can be converted to Int4 to simplify.
using Int4 = Type<TypeCategory::Integer, 4>;
if (auto *n{UnwrapArgument<SomeInteger>(args[2])}) {
if (n->GetType()->kind != 4) {
*args[2] =
AsGenericExpr(Fold(context, ConvertToType<Int4>(std::move(*n))));
}
}
const auto fptr{
name == "dshiftl" ? &Scalar<T>::DSHIFTL : &Scalar<T>::DSHIFTR};
return FoldElementalIntrinsic<T, T, T, Int4>(context, std::move(funcRef),
ScalarFunc<T, T, T, Int4>(
[&fptr](const Scalar<T> &i, const Scalar<T> &j,
const Scalar<Int4> &shift) -> Scalar<T> {
return std::invoke(
fptr, i, j, static_cast<int>(shift.ToInt64()));
}));
} else if (name == "exponent") {
if (auto *sx{UnwrapArgument<SomeReal>(args[0])}) {
return std::visit(
[&funcRef, &context](const auto &x) -> Expr<T> {
using TR = typename std::decay_t<decltype(x)>::Result;
return FoldElementalIntrinsic<T, TR>(context, std::move(funcRef),
&Scalar<TR>::template EXPONENT<Scalar<T>>);
},
sx->u);
} else {
common::die("exponent argument must be real");
}
} else if (name == "iand" || name == "ior" || name == "ieor") {
// convert boz
for (int i{0}; i <= 1; ++i) {
if (auto *x{UnwrapBozArgument(args[i])}) {
*args[i] =
AsGenericExpr(Fold(context, ConvertToType<T>(std::move(*x))));
}
}
auto fptr{&Scalar<T>::IAND};
if (name == "iand") { // done in fptr declaration
} else if (name == "ior") {
fptr = &Scalar<T>::IOR;
} else if (name == "ieor") {
fptr = &Scalar<T>::IEOR;
} else {
common::die("missing case to fold intrinsic function %s", name.c_str());
}
return FoldElementalIntrinsic<T, T, T>(
context, std::move(funcRef), ScalarFunc<T, T, T>(fptr));
} else if (name == "ibclr" || name == "ibset" || name == "ishft" ||
name == "shifta" || name == "shiftr" || name == "shiftl") {
// Second argument can be of any kind. However, it must be smaller or
// equal than BIT_SIZE. It can be converted to Int4 to simplify.
using Int4 = Type<TypeCategory::Integer, 4>;
if (auto *n{UnwrapArgument<SomeInteger>(args[1])}) {
if (n->GetType()->kind != 4) {
*args[1] =
AsGenericExpr(Fold(context, ConvertToType<Int4>(std::move(*n))));
}
}
auto fptr{&Scalar<T>::IBCLR};
if (name == "ibclr") { // done in fprt definition
} else if (name == "ibset") {
fptr = &Scalar<T>::IBSET;
} else if (name == "ibshft") {
fptr = &Scalar<T>::ISHFT;
} else if (name == "shifta") {
fptr = &Scalar<T>::SHIFTA;
} else if (name == "shiftr") {
fptr = &Scalar<T>::SHIFTR;
} else if (name == "shiftl") {
fptr = &Scalar<T>::SHIFTL;
} else {
common::die("missing case to fold intrinsic function %s", name.c_str());
}
return FoldElementalIntrinsic<T, T, Int4>(context, std::move(funcRef),
ScalarFunc<T, T, Int4>([&fptr](const Scalar<T> &i,
const Scalar<Int4> &pos) -> Scalar<T> {
return std::invoke(fptr, i, static_cast<int>(pos.ToInt64()));
}));
} else if (name == "int") {
if (auto *expr{args[0].value().GetExpr()}) {
return std::visit(
[&](auto &&x) -> Expr<T> {
using From = std::decay_t<decltype(x)>;
if constexpr (std::is_same_v<From, BOZLiteralConstant> ||
std::is_same_v<From, Expr<SomeReal>> ||
std::is_same_v<From, Expr<SomeInteger>> ||
std::is_same_v<From, Expr<SomeComplex>>) {
return Fold(context, ConvertToType<T>(std::move(x)));
}
common::die("int() argument type not valid");
},
std::move(expr->u));
}
} else if (name == "kind") {
if constexpr (common::HasMember<T, IntegerTypes>) {
return Expr<T>{args[0].value().GetType()->kind};
} else {
common::die("kind() result not integral");
}
} else if (name == "leadz" || name == "trailz" || name == "poppar" ||
name == "popcnt") {
if (auto *sn{UnwrapArgument<SomeInteger>(args[0])}) {
return std::visit(
[&funcRef, &context, &name](const auto &n) -> Expr<T> {
using TI = typename std::decay_t<decltype(n)>::Result;
if (name == "poppar") {
return FoldElementalIntrinsic<T, TI>(context,
std::move(funcRef),
ScalarFunc<T, TI>([](const Scalar<TI> &i) -> Scalar<T> {
return Scalar<T>{i.POPPAR() ? 1 : 0};
}));
}
auto fptr{&Scalar<TI>::LEADZ};
if (name == "leadz") { // done in fprt definition
} else if (name == "trailz") {
fptr = &Scalar<TI>::TRAILZ;
} else if (name == "popcnt") {
fptr = &Scalar<TI>::POPCNT;
} else {
common::die(
"missing case to fold intrinsic function %s", name.c_str());
}
return FoldElementalIntrinsic<T, TI>(context, std::move(funcRef),
ScalarFunc<T, TI>([&fptr](const Scalar<TI> &i) -> Scalar<T> {
return Scalar<T>{std::invoke(fptr, i)};
}));
},
sn->u);
} else {
common::die("leadz argument must be integer");
}
} else if (name == "len") {
if (auto *charExpr{UnwrapArgument<SomeCharacter>(args[0])}) {
return std::visit(
[&](auto &kx) {
if constexpr (std::is_same_v<T, SubscriptInteger>) {
return kx.LEN();
} else {
return Fold(context, ConvertToType<T>(kx.LEN()));
}
},
charExpr->u);
} else {
common::die("len() argument must be of character type");
}
} else if (name == "maskl" || name == "maskr") {
// Argument can be of any kind but value has to be smaller than bit_size.
// It can be safely converted to Int4 to simplify.
using Int4 = Type<TypeCategory::Integer, 4>;
if (auto *n{UnwrapArgument<SomeInteger>(args[0])}) {
if (n->GetType()->kind != 4) {
*args[0] =
AsGenericExpr(Fold(context, ConvertToType<Int4>(std::move(*n))));
}
}
const auto fptr{name == "maskl" ? &Scalar<T>::MASKL : &Scalar<T>::MASKR};
return FoldElementalIntrinsic<T, Int4>(context, std::move(funcRef),
ScalarFunc<T, Int4>([&fptr](const Scalar<Int4> &places) -> Scalar<T> {
return fptr(static_cast<int>(places.ToInt64()));
}));
} else if (name == "merge_bits") {
// convert boz
for (int i{0}; i <= 2; ++i) {
if (auto *x{UnwrapBozArgument(args[i])}) {
*args[i] =
AsGenericExpr(Fold(context, ConvertToType<T>(std::move(*x))));
}
}
return FoldElementalIntrinsic<T, T, T, T>(
context, std::move(funcRef), &Scalar<T>::MERGE_BITS);
} else if (name == "rank") {
// TODO assumed-rank dummy argument
return Expr<T>{args[0].value().Rank()};
} else if (name == "shape") {
if (auto shape{GetShape(context, args[0].value())}) {
if (auto shapeExpr{AsExtentArrayExpr(*shape)}) {
return Fold(context, ConvertToType<T>(std::move(*shapeExpr)));
}
}
} else if (name == "size") {
if (auto shape{GetShape(context, args[0].value())}) {
if (auto &dimArg{args[1]}) { // DIM= is present, get one extent
if (auto *expr{dimArg->GetExpr()}) {
if (auto dim{ToInt64(*expr)}) {
std::int64_t rank = shape->size();
if (*dim >= 1 && *dim <= rank) {
if (auto &extent{shape->at(*dim - 1)}) {
return Fold(context, ConvertToType<T>(std::move(*extent)));
}
} else {
context.messages().Say(
"size(array,dim=%jd) dimension is out of range for rank-%d array"_en_US,
static_cast<std::intmax_t>(*dim), static_cast<int>(rank));
}
}
}
} else if (auto extents{
common::AllElementsPresent(std::move(*shape))}) {
// DIM= is absent; compute PRODUCT(SHAPE())
ExtentExpr product{1};
for (auto &&extent : std::move(*extents)) {
product = std::move(product) * std::move(extent);
}
return Expr<T>{ConvertToType<T>(Fold(context, std::move(product)))};
}
}
}
// TODO:
// ceiling, count, cshift, dot_product, eoshift,
// findloc, floor, iachar, iall, iany, iparity, ibits, ichar, image_status,
// index, ishftc, lbound, len_trim, matmul, max, maxloc, maxval, merge, min,
// minloc, minval, mod, modulo, nint, not, pack, product, reduce, reshape,
// scan, selected_char_kind, selected_int_kind, selected_real_kind,
// sign, spread, sum, transfer, transpose, ubound, unpack, verify
}
return Expr<T>{std::move(funcRef)};
}
template<int KIND>
Expr<Type<TypeCategory::Real, KIND>> FoldOperation(FoldingContext &context,
FunctionRef<Type<TypeCategory::Real, KIND>> &&funcRef) {
using T = Type<TypeCategory::Real, KIND>;
using ComplexT = Type<TypeCategory::Complex, KIND>;
ActualArguments &args{funcRef.arguments()};
for (std::optional<ActualArgument> &arg : args) {
if (arg.has_value()) {
if (auto *expr{arg->GetExpr()}) {
*expr = FoldOperation(context, std::move(*expr));
}
}
}
if (auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)}) {
const std::string name{intrinsic->name};
if (name == "acos" || name == "acosh" || name == "asin" ||
name == "asinh" || (name == "atan" && args.size() == 1) ||
name == "atanh" || name == "bessel_j0" || name == "bessel_j1" ||
name == "bessel_y0" || name == "bessel_y1" || name == "cos" ||
name == "cosh" || name == "erf" || name == "erfc" ||
name == "erfc_scaled" || name == "exp" || name == "gamma" ||
name == "log" || name == "log10" || name == "log_gamma" ||
name == "sin" || name == "sinh" || name == "sqrt" || name == "tan" ||
name == "tanh") {
CHECK(args.size() == 1);
if (auto callable{context.hostIntrinsicsLibrary()
.GetHostProcedureWrapper<Scalar, T, T>(name)}) {
return FoldElementalIntrinsic<T, T>(
context, std::move(funcRef), *callable);
} else {
context.messages().Say(
"%s(real(kind=%d)) cannot be folded on host"_en_US, name.c_str(),
KIND);
}
}
if (name == "atan" || name == "atan2" || name == "hypot" || name == "mod") {
std::string localName{name == "atan2" ? "atan" : name};
CHECK(args.size() == 2);
if (auto callable{
context.hostIntrinsicsLibrary()
.GetHostProcedureWrapper<Scalar, T, T, T>(localName)}) {
return FoldElementalIntrinsic<T, T, T>(
context, std::move(funcRef), *callable);
} else {
context.messages().Say(
"%s(real(kind=%d), real(kind%d)) cannot be folded on host"_en_US,
name.c_str(), KIND, KIND);
}
} else if (name == "bessel_jn" || name == "bessel_yn") {
if (args.size() == 2) { // elemental
// runtime functions use int arg
using Int4 = Type<TypeCategory::Integer, 4>;
if (auto *n{UnwrapArgument<SomeInteger>(args[0])}) {
if (n->GetType()->kind != 4) {
*args[0] = AsGenericExpr(
Fold(context, ConvertToType<Int4>(std::move(*n))));
}
}
if (auto callable{
context.hostIntrinsicsLibrary()
.GetHostProcedureWrapper<Scalar, T, Int4, T>(name)}) {
return FoldElementalIntrinsic<T, Int4, T>(
context, std::move(funcRef), *callable);
} else {
context.messages().Say(
"%s(integer(kind=4), real(kind=%d)) cannot be folded on host"_en_US,
name.c_str(), KIND);
}
}
} else if (name == "abs") {
// Argument can be complex or real
if (auto *x{UnwrapArgument<SomeReal>(args[0])}) {
return FoldElementalIntrinsic<T, T>(
context, std::move(funcRef), &Scalar<T>::ABS);
} else if (auto *z{UnwrapArgument<SomeComplex>(args[0])}) {
if (auto callable{
context.hostIntrinsicsLibrary()
.GetHostProcedureWrapper<Scalar, T, ComplexT>("abs")}) {
return FoldElementalIntrinsic<T, ComplexT>(
context, std::move(funcRef), *callable);
} else {
context.messages().Say(
"abs(complex(kind=%d)) cannot be folded on host"_en_US, KIND);
}
} else {
common::die(" unexpected argument type inside abs");
}
} else if (name == "aimag") {
return FoldElementalIntrinsic<T, ComplexT>(
context, std::move(funcRef), &Scalar<ComplexT>::AIMAG);
} else if (name == "aint") {
// Convert argument to the requested kind before calling aint
if (auto *x{UnwrapArgument<SomeReal>(args[0])}) {
if (!(x->GetType()->kind == T::kind)) {
*args[0] =
AsGenericExpr(Fold(context, ConvertToType<T>(std::move(*x))));
}
}
return FoldElementalIntrinsic<T, T>(context, std::move(funcRef),
ScalarFunc<T, T>([&name, &context](const Scalar<T> &x) -> Scalar<T> {
ValueWithRealFlags<Scalar<T>> y{x.AINT()};
if (y.flags.test(RealFlag::Overflow)) {
context.messages().Say(
"%s intrinsic folding overflow"_en_US, name.c_str());
}
return y.value;
}));
} else if (name == "dprod") {
if (auto *x{UnwrapArgument<SomeReal>(args[0])}) {
if (auto *y{UnwrapArgument<SomeReal>(args[1])}) {
return Fold(context,
Expr<T>{Multiply<T>{ConvertToType<T>(std::move(*x)),
ConvertToType<T>(std::move(*y))}});
}
}
common::die("Wrong argument type in dprod()");
} else if (name == "epsilon") {
return Expr<T>{Constant<T>{Scalar<T>::EPSILON()}};
} else if (name == "real") {
if (auto *expr{args[0].value().GetExpr()}) {
return std::visit(
[&](auto &&x) -> Expr<T> {
using From = std::decay_t<decltype(x)>;
if constexpr (std::is_same_v<From, BOZLiteralConstant>) {
typename T::Scalar::Word::ValueWithOverflow result{
T::Scalar::Word::ConvertUnsigned(x)};
if (result.overflow) { // C1601
context.messages().Say(
"Non null truncated bits of boz literal constant in REAL intrinsic"_en_US);
}
return Expr<T>{Constant<T>{Scalar<T>(std::move(result.value))}};
} else if constexpr (std::is_same_v<From, Expr<SomeReal>> ||
std::is_same_v<From, Expr<SomeInteger>> ||
std::is_same_v<From, Expr<SomeComplex>>) {
return Fold(context, ConvertToType<T>(std::move(x)));
}
common::die("real() argument type not valid");
},
std::move(expr->u));
}
}
// TODO: anint, cshift, dim, dot_product, eoshift, fraction, huge, matmul,
// max, maxval, merge, min, minval, modulo, nearest, norm2, pack, product,
// reduce, reshape, rrspacing, scale, set_exponent, sign, spacing, spread,
// sum, tiny, transfer, transpose, unpack, bessel_jn (transformational) and
// bessel_yn (transformational)
}
return Expr<T>{std::move(funcRef)};
}
template<int KIND>
Expr<Type<TypeCategory::Complex, KIND>> FoldOperation(FoldingContext &context,
FunctionRef<Type<TypeCategory::Complex, KIND>> &&funcRef) {
using T = Type<TypeCategory::Complex, KIND>;
ActualArguments &args{funcRef.arguments()};
for (std::optional<ActualArgument> &arg : args) {
if (arg.has_value()) {
if (auto *expr{arg->GetExpr()}) {
*expr = FoldOperation(context, std::move(*expr));
}
}
}
if (auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)}) {
const std::string name{intrinsic->name};
if (name == "acos" || name == "acosh" || name == "asin" ||
name == "asinh" || name == "atan" || name == "atanh" || name == "cos" ||
name == "cosh" || name == "exp" || name == "log" || name == "sin" ||
name == "sinh" || name == "sqrt" || name == "tan" || name == "tanh") {
if (auto callable{context.hostIntrinsicsLibrary()
.GetHostProcedureWrapper<Scalar, T, T>(name)}) {
return FoldElementalIntrinsic<T, T>(
context, std::move(funcRef), *callable);
} else {
context.messages().Say(
"%s(complex(kind=%d)) cannot be folded on host"_en_US, name.c_str(),
KIND);
}
} else if (name == "conjg") {
return FoldElementalIntrinsic<T, T>(
context, std::move(funcRef), &Scalar<T>::CONJG);
} else if (name == "cmplx") {
if (args.size() == 2) {
if (auto *x{UnwrapArgument<SomeComplex>(args[0])}) {
return Fold(context, ConvertToType<T>(std::move(*x)));
} else {
common::die("x must be complex in cmplx(x[, kind])");
}
} else {
CHECK(args.size() == 3);
using Part = typename T::Part;
Expr<SomeType> im{args[1].has_value()
? std::move(*args[1].value().GetExpr())
: AsGenericExpr(Constant<Part>{Scalar<Part>{}})};
Expr<SomeType> re{std::move(*args[0].value().GetExpr())};
int reRank{re.Rank()};
int imRank{im.Rank()};
semantics::Attrs attrs;
attrs.set(semantics::Attr::ELEMENTAL);
auto reReal{
FunctionRef<Part>{ProcedureDesignator{SpecificIntrinsic{
"real", Part::GetType(), reRank, attrs}},
ActualArguments{ActualArgument{std::move(re)}}}};
auto imReal{
FunctionRef<Part>{ProcedureDesignator{SpecificIntrinsic{
"real", Part::GetType(), imRank, attrs}},
ActualArguments{ActualArgument{std::move(im)}}}};
return Fold(context,
Expr<T>{ComplexConstructor<T::kind>{
Expr<Part>{std::move(reReal)}, Expr<Part>{std::move(imReal)}}});
}
}
// TODO: cshift, dot_product, eoshift, matmul, merge, pack, product,
// reduce, reshape, spread, sum, transfer, transpose, unpack
}
return Expr<T>{std::move(funcRef)};
}
template<int KIND>
Expr<Type<TypeCategory::Logical, KIND>> FoldOperation(FoldingContext &context,
FunctionRef<Type<TypeCategory::Logical, KIND>> &&funcRef) {
using T = Type<TypeCategory::Logical, KIND>;
ActualArguments &args{funcRef.arguments()};
for (std::optional<ActualArgument> &arg : args) {
if (arg.has_value()) {
if (auto *expr{arg->GetExpr()}) {
*expr = FoldOperation(context, std::move(*expr));
}
}
}
if (auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)}) {
std::string name{intrinsic->name};
if (name == "bge" || name == "bgt" || name == "ble" || name == "blt") {
using LargestInt = Type<TypeCategory::Integer, 16>;
static_assert(std::is_same_v<Scalar<LargestInt>, BOZLiteralConstant>);
// Arguments do not have to be of the same integer type. Convert all
// arguments to the biggest integer type before comparing them to
// simplify.
for (int i{0}; i <= 1; ++i) {
if (auto *x{UnwrapArgument<SomeInteger>(args[i])}) {
*args[i] = AsGenericExpr(
Fold(context, ConvertToType<LargestInt>(std::move(*x))));
} else if (auto *x{UnwrapBozArgument(args[i])}) {
*args[i] = AsGenericExpr(Constant<LargestInt>{std::move(*x)});
}
}
auto fptr{&Scalar<LargestInt>::BGE};
if (name == "bge") { // done in fptr declaration
} else if (name == "bgt") {
fptr = &Scalar<LargestInt>::BGT;
} else if (name == "ble") {
fptr = &Scalar<LargestInt>::BLE;
} else if (name == "blt") {
fptr = &Scalar<LargestInt>::BLT;
} else {
common::die("missing case to fold intrinsic function %s", name.c_str());
}
return FoldElementalIntrinsic<T, LargestInt, LargestInt>(context,
std::move(funcRef),
ScalarFunc<T, LargestInt, LargestInt>(
[&fptr](
const Scalar<LargestInt> &i, const Scalar<LargestInt> &j) {
return Scalar<T>{std::invoke(fptr, i, j)};
}));
}
// TODO: all, any, btest, cshift, dot_product, eoshift, is_iostat_end,
// is_iostat_eor, lge, lgt, lle, llt, logical, matmul, merge, out_of_range,
// pack, parity, reduce, reshape, spread, transfer, transpose, unpack
}
return Expr<T>{std::move(funcRef)};
}
template<typename T>
Expr<T> FoldOperation(FoldingContext &context, 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{
[&](const Symbol *symbol) { return Expr<T>{std::move(designator)}; },
[&](auto &&x) {
return Expr<T>{Designator<T>{FoldOperation(context, std::move(x))}};
},
},
std::move(designator.u));
}
// Array constructor folding
Expr<ImpliedDoIndex::Result> FoldOperation(
FoldingContext &context, ImpliedDoIndex &&iDo) {
if (std::optional<std::int64_t> value{context.GetImpliedDo(iDo.name)}) {
return Expr<ImpliedDoIndex::Result>{*value};
} else {
return Expr<ImpliedDoIndex::Result>{std::move(iDo)};
}
}
template<typename T> class ArrayConstructorFolder {
public:
explicit ArrayConstructorFolder(const FoldingContext &c) : context_{c} {}
Expr<T> FoldArray(ArrayConstructor<T> &&array) {
if (FoldArray(array)) {
auto n{static_cast<std::int64_t>(elements_.size())};
if constexpr (std::is_same_v<T, SomeDerived>) {
return Expr<T>{Constant<T>{array.derivedTypeSpec(),
std::move(elements_), ConstantSubscripts{n}}};
} else if constexpr (T::category == TypeCategory::Character) {
auto length{Fold(context_, common::Clone(array.LEN()))};
if (std::optional<std::int64_t> 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 (auto *c{UnwrapExpr<Constant<T>>(folded)}) {
// Copy elements in Fortran array element order
ConstantSubscripts shape{c->shape()};
int rank{c->Rank()};
ConstantSubscripts index(shape.size(), 1);
for (std::size_t n{c->size()}; n-- > 0;) {
if constexpr (std::is_same_v<T, SomeDerived>) {
elements_.emplace_back(c->derivedTypeSpec(), c->At(index));
} else {
elements_.emplace_back(c->At(index));
}
for (int d{0}; d < rank; ++d) {
if (++index[d] <= shape[d]) {
break;
}
index[d] = 1;
}
}
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<std::int64_t> start{ToInt64(lower)}, end{ToInt64(upper)},
step{ToInt64(stride)};
if (start.has_value() && end.has_value() && step.has_value()) {
if (*step == 0) {
return false;
}
bool result{true};
std::int64_t &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) {
ArrayConstructorFolder<T> folder{context};
Expr<T> result{folder.FoldArray(std::move(array))};
return result;
}
Expr<SomeDerived> FoldOperation(
FoldingContext &context, StructureConstructor &&structure) {
StructureConstructor result{structure.derivedTypeSpec()};
for (auto &&[symbol, value] : std::move(structure)) {
result.Add(*symbol, Fold(context, std::move(value.value())));
}
return Expr<SomeDerived>{Constant<SomeDerived>{result}};
}
// Substitute a bare type parameter reference with its value if it has one now
template<int KIND>
Expr<Type<TypeCategory::Integer, KIND>> FoldOperation(
FoldingContext &context, TypeParamInquiry<KIND> &&inquiry) {
using IntKIND = Type<TypeCategory::Integer, KIND>;
if (Component * component{common::Unwrap<Component>(inquiry.base())}) {
return Expr<IntKIND>{TypeParamInquiry<KIND>{
FoldOperation(context, std::move(*component)), inquiry.parameter()}};
}
if (context.pdtInstance() != nullptr &&
std::get<const Symbol *>(inquiry.base()) == nullptr) {
// "bare" type parameter: replace with actual value
const semantics::Scope *scope{context.pdtInstance()->scope()};
CHECK(scope != nullptr);
auto iter{scope->find(inquiry.parameter().name())};
if (iter != scope->end()) {
const Symbol &symbol{*iter->second};
const auto *details{symbol.detailsIf<semantics::TypeParamDetails>()};
if (details && details->init().has_value()) {
Expr<SomeInteger> expr{*details->init()};
return Fold(context,
Expr<IntKIND>{
Convert<IntKIND, TypeCategory::Integer>(std::move(expr))});
}
} else if (const auto *value{context.pdtInstance()->FindParameter(
inquiry.parameter().name())}) {
// Parameter of a parent derived type; these are saved in the spec.
if (value->isExplicit()) {
return Fold(context,
Expr<IntKIND>{Convert<IntKIND, TypeCategory::Integer>(
Expr<SomeInteger>{value->GetExplicit().value()})});
}
}
}
return Expr<IntKIND>{std::move(inquiry)};
}
// 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{UnwrapExpr<Constant<T>>(expr)}) {
ArrayConstructor<T> result{expr};
if (c->size() > 0) {
ConstantSubscripts at{InitialSubscripts(c->shape())};
do {
result.Push(Expr<T>{Constant<T>{c->At(at)}});
} while (IncrementSubscripts(at, c->shape()));
}
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::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.has_value()) {
if (auto *constant{UnwrapExpr<Constant<T>>(result)}) {
constant->shape() = std::move(*shape);
} else {
auto resultShape{GetShape(context, result)};
CHECK(resultShape.has_value());
auto constantShape{AsConstantShape(*resultShape)};
CHECK(constantShape.has_value());
CHECK(*shape == AsConstantExtents(*constantShape));
}
}
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 (IsGenericIntrinsicCategoryType<OPERAND>) {
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(
FoldOperation(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(FoldOperation(context, f(std::move(scalar))));
}
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(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 (IsGenericIntrinsicCategoryType<RIGHT>) {
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(FoldOperation(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(FoldOperation(
context, f(std::move(leftScalar), std::move(rightScalar))));
++rightIter;
}
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(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(FoldOperation(
context, f(std::move(leftScalar), Expr<RIGHT>{rightScalar})));
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(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 (IsGenericIntrinsicCategoryType<RIGHT>) {
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(FoldOperation(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(FoldOperation(
context, f(Expr<LEFT>{leftScalar}, std::move(rightScalar))));
}
}
return FromArrayConstructor(
context, std::move(result), AsConstantExtents(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)}};
}});
}
// Predicate: is a scalar expression suitable for naive scalar expansion
// in the flattening of an array expression?
// TODO: capture such scalar expansions in temporaries, flatten everything
struct UnexpandabilityFindingVisitor : public virtual VisitorBase<bool> {
using Result = bool;
explicit UnexpandabilityFindingVisitor(int) { result() = false; }
template<typename T> void Handle(FunctionRef<T> &) { Return(true); }
template<typename T> void Handle(CoarrayRef &) { Return(true); }
};
template<typename T> bool IsExpandableScalar(const Expr<T> &expr) {
return Visitor<UnexpandabilityFindingVisitor>{0}.Traverse(expr);
}
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)}) {
CheckConformance(context.messages(), *leftShape, *rightShape);
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;
}
return std::visit(
[&](auto &kindExpr) -> Expr<TO> {
using Operand = ResultType<decltype(kindExpr)>;
char buffer[64];
if (auto value{GetScalarConstantValue<Operand>(kindExpr)}) {
if constexpr (TO::category == TypeCategory::Integer) {
if constexpr (Operand::category == TypeCategory::Integer) {
auto converted{Scalar<TO>::ConvertSigned(*value)};
if (converted.overflow) {
context.messages().Say(
"INTEGER(%d) to INTEGER(%d) conversion overflowed"_en_US,
Operand::kind, TO::kind);
}
return ScalarConstantToExpr(std::move(converted.value));
} else if constexpr (Operand::category == TypeCategory::Real) {
auto converted{value->template ToInteger<Scalar<TO>>()};
if (converted.flags.test(RealFlag::InvalidArgument)) {
context.messages().Say(
"REAL(%d) to INTEGER(%d) conversion: invalid argument"_en_US,
Operand::kind, TO::kind);
} else if (converted.flags.test(RealFlag::Overflow)) {
context.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 (Operand::category == 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(context, converted.flags, buffer);
}
return ScalarConstantToExpr(std::move(converted.value));
} else if constexpr (Operand::category == 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(context, converted.flags, buffer);
}
if (context.flushSubnormalsToZero()) {
converted.value = converted.value.FlushSubnormalToZero();
}
return ScalarConstantToExpr(std::move(converted.value));
}
} else if constexpr (TO::category == TypeCategory::Character &&
Operand::category == TypeCategory::Character) {
if (auto converted{ConvertString<Scalar<TO>>(std::move(*value))}) {
return ScalarConstantToExpr(std::move(*converted));
}
} else if constexpr (TO::category == TypeCategory::Logical &&
Operand::category == TypeCategory::Logical) {
return Expr<TO>{value->IsTrue()};
}
}
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}}}};
}
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 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)};
}
template<int KIND>
Expr<Type<TypeCategory::Real, KIND>> FoldOperation(
FoldingContext &context, ComplexComponent<KIND> &&x) {
using Operand = Type<TypeCategory::Complex, KIND>;
using Result = Type<TypeCategory::Real, KIND>;
if (auto array{ApplyElementwise(context, x,
std::function<Expr<Result>(Expr<Operand> &&)>{
[=](Expr<Operand> &&operand) {
return Expr<Result>{ComplexComponent<KIND>{
x.isImaginaryPart, std::move(operand)}};
}})}) {
return *array;
}
using Part = Type<TypeCategory::Real, KIND>;
auto &operand{x.left()};
if (auto value{GetScalarConstantValue<Operand>(operand)}) {
if (x.isImaginaryPart) {
return Expr<Part>{Constant<Part>{value->AIMAG()}};
} else {
return Expr<Part>{Constant<Part>{value->REAL()}};
}
}
return Expr<Part>{std::move(x)};
}
template<int KIND>
Expr<Type<TypeCategory::Logical, KIND>> FoldOperation(
FoldingContext &context, Not<KIND> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
using Ty = Type<TypeCategory::Logical, KIND>;
auto &operand{x.left()};
if (auto value{GetScalarConstantValue<Ty>(operand)}) {
return Expr<Ty>{Constant<Ty>{!value->IsTrue()}};
}
return Expr<Ty>{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}};
}
}
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);
}
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 {
// TODO: real & complex power with non-integral exponent
}
}
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)}) {
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 {
if (x.ordering == Compare(folded->first, folded->second)) {
return Expr<T>{Constant<T>{folded->first}};
}
}
return Expr<T>{Constant<T>{folded->second}};
}
return Expr<T>{std::move(x)};
}
template<int KIND>
Expr<Type<TypeCategory::Complex, KIND>> FoldOperation(
FoldingContext &context, ComplexConstructor<KIND> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
using Result = Type<TypeCategory::Complex, KIND>;
if (auto folded{OperandsAreConstants(x)}) {
return Expr<Result>{
Constant<Result>{Scalar<Result>{folded->first, folded->second}}};
}
return Expr<Result>{std::move(x)};
}
template<int KIND>
Expr<Type<TypeCategory::Character, KIND>> FoldOperation(
FoldingContext &context, Concat<KIND> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
using Result = Type<TypeCategory::Character, KIND>;
if (auto folded{OperandsAreConstants(x)}) {
return Expr<Result>{Constant<Result>{folded->first + folded->second}};
}
return Expr<Result>{std::move(x)};
}
template<int KIND>
Expr<Type<TypeCategory::Character, KIND>> FoldOperation(
FoldingContext &context, SetLength<KIND> &&x) {
if (auto array{ApplyElementwise(context, x)}) {
return *array;
}
using Result = Type<TypeCategory::Character, KIND>;
if (auto folded{OperandsAreConstants(x)}) {
auto oldLength{static_cast<std::int64_t>(folded->first.size())};
auto newLength{folded->second.ToInt64()};
if (newLength < oldLength) {
folded->first.erase(newLength);
} else {
folded->first.append(newLength - oldLength, ' ');
}
CHECK(static_cast<std::int64_t>(folded->first.size()) == newLength);
return Expr<Result>{Constant<Result>{std::move(folded->first)}};
}
return Expr<Result>{std::move(x)};
}
template<typename T>
Expr<LogicalResult> FoldOperation(
FoldingContext &context, Relational<T> &&relation) {
if (auto array{ApplyElementwise(context, relation,
std::function<Expr<LogicalResult>(Expr<T> &&, Expr<T> &&)>{
[=](Expr<T> &&x, Expr<T> &&y) {
return Expr<LogicalResult>{Relational<SomeType>{
Relational<T>{relation.opr, std::move(x), std::move(y)}}};
}})}) {
return *array;
}
if (auto folded{OperandsAreConstants(relation)}) {
bool result{};
if constexpr (T::category == TypeCategory::Integer) {
result =
Satisfies(relation.opr, folded->first.CompareSigned(folded->second));
} else if constexpr (T::category == TypeCategory::Real) {
result = Satisfies(relation.opr, folded->first.Compare(folded->second));
} else if constexpr (T::category == TypeCategory::Character) {
result = Satisfies(relation.opr, Compare(folded->first, folded->second));
} else {
static_assert(T::category != TypeCategory::Complex &&
T::category != TypeCategory::Logical);
}
return Expr<LogicalResult>{Constant<LogicalResult>{result}};
}
return Expr<LogicalResult>{Relational<SomeType>{std::move(relation)}};
}
inline Expr<LogicalResult> FoldOperation(
FoldingContext &context, Relational<SomeType> &&relation) {
return std::visit(
[&](auto &&x) {
return Expr<LogicalResult>{FoldOperation(context, std::move(x))};
},
std::move(relation.u));
}
template<int KIND>
Expr<Type<TypeCategory::Logical, KIND>> FoldOperation(
FoldingContext &context, LogicalOperation<KIND> &&operation) {
using LOGICAL = Type<TypeCategory::Logical, KIND>;
if (auto array{ApplyElementwise(context, operation,
std::function<Expr<LOGICAL>(Expr<LOGICAL> &&, Expr<LOGICAL> &&)>{
[=](Expr<LOGICAL> &&x, Expr<LOGICAL> &&y) {
return Expr<LOGICAL>{LogicalOperation<KIND>{
operation.logicalOperator, std::move(x), std::move(y)}};
}})}) {
return *array;
}
if (auto folded{OperandsAreConstants(operation)}) {
bool xt{folded->first.IsTrue()}, yt{folded->second.IsTrue()}, result{};
switch (operation.logicalOperator) {
case LogicalOperator::And: result = xt && yt; break;
case LogicalOperator::Or: result = xt || yt; break;
case LogicalOperator::Eqv: result = xt == yt; break;
case LogicalOperator::Neqv: result = xt != yt; break;
}
return Expr<LOGICAL>{Constant<LOGICAL>{result}};
}
return Expr<LOGICAL>{std::move(operation)};
}
// end per-operation folding functions
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 {
using Ty = std::decay_t<decltype(x)>;
if constexpr (std::is_same_v<Ty, BOZLiteralConstant> ||
std::is_same_v<Ty, NullPointer>) {
return std::move(expr);
} else {
return Expr<T>{Fold(context, std::move(x))};
}
}
},
std::move(expr.u));
}
FOR_EACH_TYPE_AND_KIND(template class ExpressionBase, )
// Constant expression predicate IsConstantExpr().
// This code determines whether an expression is a "constant expression"
// in the sense of section 10.1.12. This is not the same thing as being
// able to fold it (yet) into a known constant value; specifically,
// the expression may reference derived type kind parameters whose values
// are not yet known.
class IsConstantExprVisitor : public virtual VisitorBase<bool> {
public:
using Result = bool;
explicit IsConstantExprVisitor(int) { result() = true; }
template<int KIND> void Handle(const TypeParamInquiry<KIND> &inq) {
Check(inq.parameter().template get<semantics::TypeParamDetails>().attr() ==
common::TypeParamAttr::Kind);
}
void Handle(const semantics::Symbol &symbol) {
Check(symbol.attrs().test(semantics::Attr::PARAMETER));
}
void Handle(const CoarrayRef &) { Return(false); }
void Pre(const semantics::ParamValue &param) { Check(param.isExplicit()); }
template<typename T> void Pre(const FunctionRef<T> &call) {
if (const auto *intrinsic{std::get_if<SpecificIntrinsic>(&call.proc().u)}) {
Check(intrinsic->name == "kind");
// TODO: Obviously many other intrinsics can be allowed
} else {
Return(false);
}
}
private:
void Check(bool ok) {
if (!ok) {
Return(false);
}
}
};
bool IsConstantExpr(const Expr<SomeType> &expr) {
return Visitor<IsConstantExprVisitor>{0}.Traverse(expr);
}
std::optional<std::int64_t> ToInt64(const Expr<SomeInteger> &expr) {
return std::visit(
[](const auto &kindExpr) { return ToInt64(kindExpr); }, expr.u);
}
std::optional<std::int64_t> ToInt64(const Expr<SomeType> &expr) {
if (const auto *intExpr{UnwrapExpr<Expr<SomeInteger>>(expr)}) {
return ToInt64(*intExpr);
} else {
return std::nullopt;
}
}
}
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