xref: /llvm-project/flang/lib/Evaluate/fold-logical.cpp (revision e4c4841e5bbaf6d09aff65387102ed22a9eac60b)
1 //===-- lib/Evaluate/fold-logical.cpp -------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "fold-implementation.h"
10 #include "fold-reduction.h"
11 #include "flang/Evaluate/check-expression.h"
12 
13 namespace Fortran::evaluate {
14 
15 template <typename T>
16 static std::optional<Expr<SomeType>> ZeroExtend(const Constant<T> &c) {
17   std::vector<Scalar<LargestInt>> exts;
18   for (const auto &v : c.values()) {
19     exts.push_back(Scalar<LargestInt>::ConvertUnsigned(v).value);
20   }
21   return AsGenericExpr(
22       Constant<LargestInt>(std::move(exts), ConstantSubscripts(c.shape())));
23 }
24 
25 // for ALL, ANY & PARITY
26 template <typename T>
27 static Expr<T> FoldAllAnyParity(FoldingContext &context, FunctionRef<T> &&ref,
28     Scalar<T> (Scalar<T>::*operation)(const Scalar<T> &) const,
29     Scalar<T> identity) {
30   static_assert(T::category == TypeCategory::Logical);
31   using Element = Scalar<T>;
32   std::optional<int> dim;
33   if (std::optional<Constant<T>> array{
34           ProcessReductionArgs<T>(context, ref.arguments(), dim, identity,
35               /*ARRAY(MASK)=*/0, /*DIM=*/1)}) {
36     auto accumulator{[&](Element &element, const ConstantSubscripts &at) {
37       element = (element.*operation)(array->At(at));
38     }};
39     return Expr<T>{DoReduction<T>(*array, dim, identity, accumulator)};
40   }
41   return Expr<T>{std::move(ref)};
42 }
43 
44 template <int KIND>
45 Expr<Type<TypeCategory::Logical, KIND>> FoldIntrinsicFunction(
46     FoldingContext &context,
47     FunctionRef<Type<TypeCategory::Logical, KIND>> &&funcRef) {
48   using T = Type<TypeCategory::Logical, KIND>;
49   ActualArguments &args{funcRef.arguments()};
50   auto *intrinsic{std::get_if<SpecificIntrinsic>(&funcRef.proc().u)};
51   CHECK(intrinsic);
52   std::string name{intrinsic->name};
53   using SameInt = Type<TypeCategory::Integer, KIND>;
54   if (name == "all") {
55     return FoldAllAnyParity(
56         context, std::move(funcRef), &Scalar<T>::AND, Scalar<T>{true});
57   } else if (name == "any") {
58     return FoldAllAnyParity(
59         context, std::move(funcRef), &Scalar<T>::OR, Scalar<T>{false});
60   } else if (name == "associated") {
61     bool gotConstant{true};
62     const Expr<SomeType> *firstArgExpr{args[0]->UnwrapExpr()};
63     if (!firstArgExpr || !IsNullPointer(*firstArgExpr)) {
64       gotConstant = false;
65     } else if (args[1]) { // There's a second argument
66       const Expr<SomeType> *secondArgExpr{args[1]->UnwrapExpr()};
67       if (!secondArgExpr || !IsNullPointer(*secondArgExpr)) {
68         gotConstant = false;
69       }
70     }
71     return gotConstant ? Expr<T>{false} : Expr<T>{std::move(funcRef)};
72   } else if (name == "bge" || name == "bgt" || name == "ble" || name == "blt") {
73     static_assert(std::is_same_v<Scalar<LargestInt>, BOZLiteralConstant>);
74 
75     // The arguments to these intrinsics can be of different types. In that
76     // case, the shorter of the two would need to be zero-extended to match
77     // the size of the other. If at least one of the operands is not a constant,
78     // the zero-extending will be done during lowering. Otherwise, the folding
79     // must be done here.
80     std::optional<Expr<SomeType>> constArgs[2];
81     for (int i{0}; i <= 1; i++) {
82       if (BOZLiteralConstant * x{UnwrapExpr<BOZLiteralConstant>(args[i])}) {
83         constArgs[i] = AsGenericExpr(Constant<LargestInt>{std::move(*x)});
84       } else if (auto *x{UnwrapExpr<Expr<SomeInteger>>(args[i])}) {
85         common::visit(
86             [&](const auto &ix) {
87               using IntT = typename std::decay_t<decltype(ix)>::Result;
88               if (auto *c{UnwrapConstantValue<IntT>(ix)}) {
89                 constArgs[i] = ZeroExtend(*c);
90               }
91             },
92             x->u);
93       }
94     }
95 
96     if (constArgs[0] && constArgs[1]) {
97       auto fptr{&Scalar<LargestInt>::BGE};
98       if (name == "bge") { // done in fptr declaration
99       } else if (name == "bgt") {
100         fptr = &Scalar<LargestInt>::BGT;
101       } else if (name == "ble") {
102         fptr = &Scalar<LargestInt>::BLE;
103       } else if (name == "blt") {
104         fptr = &Scalar<LargestInt>::BLT;
105       } else {
106         common::die("missing case to fold intrinsic function %s", name.c_str());
107       }
108 
109       for (int i{0}; i <= 1; i++) {
110         *args[i] = std::move(constArgs[i].value());
111       }
112 
113       return FoldElementalIntrinsic<T, LargestInt, LargestInt>(context,
114           std::move(funcRef),
115           ScalarFunc<T, LargestInt, LargestInt>(
116               [&fptr](
117                   const Scalar<LargestInt> &i, const Scalar<LargestInt> &j) {
118                 return Scalar<T>{std::invoke(fptr, i, j)};
119               }));
120     } else {
121       return Expr<T>{std::move(funcRef)};
122     }
123   } else if (name == "btest") {
124     if (const auto *ix{UnwrapExpr<Expr<SomeInteger>>(args[0])}) {
125       return common::visit(
126           [&](const auto &x) {
127             using IT = ResultType<decltype(x)>;
128             return FoldElementalIntrinsic<T, IT, SameInt>(context,
129                 std::move(funcRef),
130                 ScalarFunc<T, IT, SameInt>(
131                     [&](const Scalar<IT> &x, const Scalar<SameInt> &pos) {
132                       auto posVal{pos.ToInt64()};
133                       if (posVal < 0 || posVal >= x.bits) {
134                         context.messages().Say(
135                             "POS=%jd out of range for BTEST"_err_en_US,
136                             static_cast<std::intmax_t>(posVal));
137                       }
138                       return Scalar<T>{x.BTEST(posVal)};
139                     }));
140           },
141           ix->u);
142     }
143   } else if (name == "dot_product") {
144     return FoldDotProduct<T>(context, std::move(funcRef));
145   } else if (name == "extends_type_of") {
146     // Type extension testing with EXTENDS_TYPE_OF() ignores any type
147     // parameters. Returns a constant truth value when the result is known now.
148     if (args[0] && args[1]) {
149       auto t0{args[0]->GetType()};
150       auto t1{args[1]->GetType()};
151       if (t0 && t1) {
152         if (auto result{t0->ExtendsTypeOf(*t1)}) {
153           return Expr<T>{*result};
154         }
155       }
156     }
157   } else if (name == "isnan" || name == "__builtin_ieee_is_nan") {
158     // A warning about an invalid argument is discarded from converting
159     // the argument of isnan() / IEEE_IS_NAN().
160     auto restorer{context.messages().DiscardMessages()};
161     using DefaultReal = Type<TypeCategory::Real, 4>;
162     return FoldElementalIntrinsic<T, DefaultReal>(context, std::move(funcRef),
163         ScalarFunc<T, DefaultReal>([](const Scalar<DefaultReal> &x) {
164           return Scalar<T>{x.IsNotANumber()};
165         }));
166   } else if (name == "__builtin_ieee_is_negative") {
167     auto restorer{context.messages().DiscardMessages()};
168     using DefaultReal = Type<TypeCategory::Real, 4>;
169     return FoldElementalIntrinsic<T, DefaultReal>(context, std::move(funcRef),
170         ScalarFunc<T, DefaultReal>([](const Scalar<DefaultReal> &x) {
171           return Scalar<T>{x.IsNegative()};
172         }));
173   } else if (name == "__builtin_ieee_is_normal") {
174     auto restorer{context.messages().DiscardMessages()};
175     using DefaultReal = Type<TypeCategory::Real, 4>;
176     return FoldElementalIntrinsic<T, DefaultReal>(context, std::move(funcRef),
177         ScalarFunc<T, DefaultReal>([](const Scalar<DefaultReal> &x) {
178           return Scalar<T>{x.IsNormal()};
179         }));
180   } else if (name == "is_contiguous") {
181     if (args.at(0)) {
182       if (auto *expr{args[0]->UnwrapExpr()}) {
183         if (auto contiguous{IsContiguous(*expr, context)}) {
184           return Expr<T>{*contiguous};
185         }
186       }
187     }
188   } else if (name == "lge" || name == "lgt" || name == "lle" || name == "llt") {
189     // Rewrite LGE/LGT/LLE/LLT into ASCII character relations
190     auto *cx0{UnwrapExpr<Expr<SomeCharacter>>(args[0])};
191     auto *cx1{UnwrapExpr<Expr<SomeCharacter>>(args[1])};
192     if (cx0 && cx1) {
193       return Fold(context,
194           ConvertToType<T>(
195               PackageRelation(name == "lge" ? RelationalOperator::GE
196                       : name == "lgt"       ? RelationalOperator::GT
197                       : name == "lle"       ? RelationalOperator::LE
198                                             : RelationalOperator::LT,
199                   ConvertToType<Ascii>(std::move(*cx0)),
200                   ConvertToType<Ascii>(std::move(*cx1)))));
201     }
202   } else if (name == "logical") {
203     if (auto *expr{UnwrapExpr<Expr<SomeLogical>>(args[0])}) {
204       return Fold(context, ConvertToType<T>(std::move(*expr)));
205     }
206   } else if (name == "merge") {
207     return FoldMerge<T>(context, std::move(funcRef));
208   } else if (name == "parity") {
209     return FoldAllAnyParity(
210         context, std::move(funcRef), &Scalar<T>::NEQV, Scalar<T>{false});
211   } else if (name == "same_type_as") {
212     // Type equality testing with SAME_TYPE_AS() ignores any type parameters.
213     // Returns a constant truth value when the result is known now.
214     if (args[0] && args[1]) {
215       auto t0{args[0]->GetType()};
216       auto t1{args[1]->GetType()};
217       if (t0 && t1) {
218         if (auto result{t0->SameTypeAs(*t1)}) {
219           return Expr<T>{*result};
220         }
221       }
222     }
223   } else if (name == "__builtin_ieee_support_datatype" ||
224       name == "__builtin_ieee_support_denormal" ||
225       name == "__builtin_ieee_support_divide" ||
226       name == "__builtin_ieee_support_inf" ||
227       name == "__builtin_ieee_support_io" ||
228       name == "__builtin_ieee_support_nan" ||
229       name == "__builtin_ieee_support_sqrt" ||
230       name == "__builtin_ieee_support_standard" ||
231       name == "__builtin_ieee_support_subnormal" ||
232       name == "__builtin_ieee_support_underflow_control") {
233     return Expr<T>{true};
234   }
235   // TODO: is_iostat_end,
236   // is_iostat_eor, logical, matmul, out_of_range,
237   // parity
238   return Expr<T>{std::move(funcRef)};
239 }
240 
241 template <typename T>
242 Expr<LogicalResult> FoldOperation(
243     FoldingContext &context, Relational<T> &&relation) {
244   if (auto array{ApplyElementwise(context, relation,
245           std::function<Expr<LogicalResult>(Expr<T> &&, Expr<T> &&)>{
246               [=](Expr<T> &&x, Expr<T> &&y) {
247                 return Expr<LogicalResult>{Relational<SomeType>{
248                     Relational<T>{relation.opr, std::move(x), std::move(y)}}};
249               }})}) {
250     return *array;
251   }
252   if (auto folded{OperandsAreConstants(relation)}) {
253     bool result{};
254     if constexpr (T::category == TypeCategory::Integer) {
255       result =
256           Satisfies(relation.opr, folded->first.CompareSigned(folded->second));
257     } else if constexpr (T::category == TypeCategory::Real) {
258       result = Satisfies(relation.opr, folded->first.Compare(folded->second));
259     } else if constexpr (T::category == TypeCategory::Complex) {
260       result = (relation.opr == RelationalOperator::EQ) ==
261           folded->first.Equals(folded->second);
262     } else if constexpr (T::category == TypeCategory::Character) {
263       result = Satisfies(relation.opr, Compare(folded->first, folded->second));
264     } else {
265       static_assert(T::category != TypeCategory::Logical);
266     }
267     return Expr<LogicalResult>{Constant<LogicalResult>{result}};
268   }
269   return Expr<LogicalResult>{Relational<SomeType>{std::move(relation)}};
270 }
271 
272 Expr<LogicalResult> FoldOperation(
273     FoldingContext &context, Relational<SomeType> &&relation) {
274   return common::visit(
275       [&](auto &&x) {
276         return Expr<LogicalResult>{FoldOperation(context, std::move(x))};
277       },
278       std::move(relation.u));
279 }
280 
281 template <int KIND>
282 Expr<Type<TypeCategory::Logical, KIND>> FoldOperation(
283     FoldingContext &context, Not<KIND> &&x) {
284   if (auto array{ApplyElementwise(context, x)}) {
285     return *array;
286   }
287   using Ty = Type<TypeCategory::Logical, KIND>;
288   auto &operand{x.left()};
289   if (auto value{GetScalarConstantValue<Ty>(operand)}) {
290     return Expr<Ty>{Constant<Ty>{!value->IsTrue()}};
291   }
292   return Expr<Ty>{x};
293 }
294 
295 template <int KIND>
296 Expr<Type<TypeCategory::Logical, KIND>> FoldOperation(
297     FoldingContext &context, LogicalOperation<KIND> &&operation) {
298   using LOGICAL = Type<TypeCategory::Logical, KIND>;
299   if (auto array{ApplyElementwise(context, operation,
300           std::function<Expr<LOGICAL>(Expr<LOGICAL> &&, Expr<LOGICAL> &&)>{
301               [=](Expr<LOGICAL> &&x, Expr<LOGICAL> &&y) {
302                 return Expr<LOGICAL>{LogicalOperation<KIND>{
303                     operation.logicalOperator, std::move(x), std::move(y)}};
304               }})}) {
305     return *array;
306   }
307   if (auto folded{OperandsAreConstants(operation)}) {
308     bool xt{folded->first.IsTrue()}, yt{folded->second.IsTrue()}, result{};
309     switch (operation.logicalOperator) {
310     case LogicalOperator::And:
311       result = xt && yt;
312       break;
313     case LogicalOperator::Or:
314       result = xt || yt;
315       break;
316     case LogicalOperator::Eqv:
317       result = xt == yt;
318       break;
319     case LogicalOperator::Neqv:
320       result = xt != yt;
321       break;
322     case LogicalOperator::Not:
323       DIE("not a binary operator");
324     }
325     return Expr<LOGICAL>{Constant<LOGICAL>{result}};
326   }
327   return Expr<LOGICAL>{std::move(operation)};
328 }
329 
330 #ifdef _MSC_VER // disable bogus warning about missing definitions
331 #pragma warning(disable : 4661)
332 #endif
333 FOR_EACH_LOGICAL_KIND(template class ExpressionBase, )
334 template class ExpressionBase<SomeLogical>;
335 } // namespace Fortran::evaluate
336