diff options
Diffstat (limited to 'flang/docs')
| -rw-r--r-- | flang/docs/AssumedRank.md | 6 | ||||
| -rw-r--r-- | flang/docs/C++17.md | 16 | ||||
| -rw-r--r-- | flang/docs/C++style.md | 12 | ||||
| -rw-r--r-- | flang/docs/Calls.md | 6 | ||||
| -rw-r--r-- | flang/docs/Character.md | 8 | ||||
| -rw-r--r-- | flang/docs/DoConcurrent.md | 3 | ||||
| -rw-r--r-- | flang/docs/Extensions.md | 34 | ||||
| -rw-r--r-- | flang/docs/FortranForCProgrammers.md | 2 | ||||
| -rw-r--r-- | flang/docs/FortranIR.md | 2 | ||||
| -rw-r--r-- | flang/docs/GettingInvolved.md | 2 | ||||
| -rw-r--r-- | flang/docs/Intrinsics.md | 70 |
11 files changed, 81 insertions, 80 deletions
diff --git a/flang/docs/AssumedRank.md b/flang/docs/AssumedRank.md index c5d2c3e..0154adc 100644 --- a/flang/docs/AssumedRank.md +++ b/flang/docs/AssumedRank.md @@ -101,9 +101,9 @@ Assumed-rank dummies are also represented in the represent assumed-rank in procedure characteristics. ### Runtime Representation of Assumed-Ranks -Assumed-ranks are implemented as CFI_cdesc_t (18.5.3) with the addition of an -f18 specific addendum when required for the type. This is the usual f18 -descriptor, and no changes is required to represent assumed-ranks in this data +Assumed-ranks are implemented as CFI_cdesc_t (18.5.3) with the addition of a +Flang specific addendum when required for the type. This is the usual Flang +descriptor, and no changes are required to represent assumed-ranks in this data structure. In fact, there is no difference between the runtime descriptor created for an assumed shape and the runtime descriptor created when the corresponding entity is passed as an assumed-rank. diff --git a/flang/docs/C++17.md b/flang/docs/C++17.md index f36110a..9137827 100644 --- a/flang/docs/C++17.md +++ b/flang/docs/C++17.md @@ -6,7 +6,7 @@ --> -# C++14/17 features used in f18 +# C++14/17 features used in Flang ```{contents} --- @@ -27,7 +27,7 @@ out the details of how our C++ code should look and gives guidance about feature usage. We have chosen to use some features of the recent C++17 -language standard in f18. +language standard in Flang. The most important of these are: * sum types (discriminated unions) in the form of `std::variant` * `using` template parameter packs @@ -41,7 +41,7 @@ in this list because it's not particularly well known.) ## Sum types First, some background information to explain the need for sum types -in f18. +in Flang. Fortran is notoriously problematic to lex and parse, as tokenization depends on the state of the partial parse; @@ -57,7 +57,7 @@ a unified lexer/parser. We have chosen to do so because it is simpler and should reduce both initial bugs and long-term maintenance. -Specifically, f18's parser uses the technique of recursive descent with +Specifically, Flang's parser uses the technique of recursive descent with backtracking. It is constructed as the incremental composition of pure parsing functions that each, when given a context (location in the input stream plus some state), @@ -73,7 +73,7 @@ of Fortran. The specification of Fortran uses a form of BNF with alternatives, optional elements, sequences, and lists. Each of these constructs -in the Fortran grammar maps directly in the f18 parser to both +in the Fortran grammar maps directly in Flang's parser to both the means of combining other parsers as alternatives, &c., and to the declarations of the parse tree data structures that represent the results of successful parses. @@ -87,10 +87,10 @@ The bounded polymorphism supplied by the C++17 `std::variant` fits those needs exactly. For example, production R502 in Fortran defines the top-level program unit of Fortran as being a function, subroutine, module, &c. -The `struct ProgramUnit` in the f18 parse tree header file +`struct ProgramUnit` in the Flang parse tree header file represents each program unit with a member that is a `std::variant` over the six possibilities. -Similarly, the parser for that type in the f18 grammar has six alternatives, +Similarly, the parser for that type in Flang's grammar has six alternatives, each of which constructs an instance of `ProgramUnit` upon the result of parsing a `Module`, `FunctionSubprogram`, and so on. @@ -99,7 +99,7 @@ parse is typically implemented with overloaded functions. A function instantiated on `ProgramUnit` will use `std::visit` to identify the right alternative and perform the right actions. The call to `std::visit` must pass a visitor that can handle all -of the possibilities, and f18 will fail to build if one is missing. +of the possibilities, and Flang will fail to build if one is missing. Were we unable to use `std::variant` directly, we would likely have chosen to implement a local `SumType` replacement; in the diff --git a/flang/docs/C++style.md b/flang/docs/C++style.md index cbb96f1..a4ca962 100644 --- a/flang/docs/C++style.md +++ b/flang/docs/C++style.md @@ -30,7 +30,7 @@ is clear on usage, follow it. is pretty good and comes with lots of justifications for its rules. * Reasonable exceptions to these guidelines can be made. * Be aware of some workarounds for known issues in older C++ compilers that should - still be able to compile f18. They are listed at the end of this document. + still be able to compile Flang. They are listed at the end of this document. ## In particular: @@ -261,7 +261,7 @@ move semantics, member access, and comparison for equality; suitable for use in `std::variant<>`. * `std::unique_ptr<>`: A nullable pointer with ownership, null by default, not copyable, reassignable. -F18 has a helpful `Deleter<>` class template that makes `unique_ptr<>` +Flang has a helpful `Deleter<>` class template that makes `unique_ptr<>` easier to use with forward-referenced data types. * `std::shared_ptr<>`: A nullable pointer with shared ownership via reference counting, null by default, shallowly copyable, reassignable, and slow. @@ -312,9 +312,9 @@ Consistency is one of many aspects in the pursuit of clarity, but not an end in itself. ## C++ compiler bug workarounds -Below is a list of workarounds for C++ compiler bugs met with f18 that, even -if the bugs are fixed in latest C++ compiler versions, need to be applied so -that all desired tool-chains can compile f18. +Below is a list of workarounds for C++ compiler bugs encountered when building +Flang. Even if the bugs are fixed in latest C++ compiler versions, these need to +be applied so that all desired tool-chains can compile Flang. ### Explicitly move noncopyable local variable into optional results @@ -338,7 +338,7 @@ std::optional<CantBeCopied> fooOK() { } ``` The underlying bug is actually not specific to `std::optional` but this is the most common -case in f18 where the issue may occur. The actual bug can be reproduced with any class `B` +case in Flang where the issue may occur. The actual bug can be reproduced with any class `B` that has a perfect forwarding constructor taking `CantBeCopied` as argument: `template<typename CantBeCopied> B(CantBeCopied&& x) x_{std::forward<CantBeCopied>(x)} {}`. In such scenarios, Ubuntu 18.04 g++ fails to instantiate the move constructor diff --git a/flang/docs/Calls.md b/flang/docs/Calls.md index f518dc0..f27af1a 100644 --- a/flang/docs/Calls.md +++ b/flang/docs/Calls.md @@ -529,7 +529,7 @@ PGI passes host instance links in descriptors in additional arguments that are not always successfully forwarded across implicit interfaces, sometimes leading to crashes when they turn out to be needed. -F18 will manage a pool of trampolines in its runtime support library +Flang will manage a pool of trampolines in its runtime support library that can be used to pass internal procedures as effective arguments to F77ish procedures, so that a bare code address can serve to represent the effective argument. @@ -569,14 +569,14 @@ Fortran 2018 explicitly enables us to do this with a correction to Fortran 2003 in 4.3.4(5). Last, there must be reasonably permanent naming conventions used -by the F18 runtime library for those unrestricted specific intrinsic +by Flang's runtime library for those unrestricted specific intrinsic functions (table 16.2 in 16.8) and extensions that can be passed as arguments. In these cases where external naming is at the discretion of the implementation, we should use names that are not in the C language user namespace, begin with something that identifies -the current incompatible version of F18, the module, the submodule, and +the current incompatible version of Flang, the module, the submodule, and elemental SIMD width, and are followed by the external name. The parts of the external name can be separated by some character that is acceptable for use in LLVM IR and assembly language but not in user diff --git a/flang/docs/Character.md b/flang/docs/Character.md index 4e1d407..96e0a06 100644 --- a/flang/docs/Character.md +++ b/flang/docs/Character.md @@ -6,7 +6,7 @@ --> -# Implementation of `CHARACTER` types in f18 +# Implementation of `CHARACTER` types in Flang ```{contents} --- @@ -16,7 +16,7 @@ local: ## Kinds and Character Sets -The f18 compiler and runtime support three kinds of the intrinsic +The Flang compiler and runtime support three kinds of the intrinsic `CHARACTER` type of Fortran 2018. The default (`CHARACTER(KIND=1)`) holds 8-bit character codes; `CHARACTER(KIND=2)` holds 16-bit character codes; @@ -108,12 +108,12 @@ The result of `//` may be used * as the value of a specifier of an I/O statement, * or as the value of a statement function. -The f18 compiler has a general (but slow) means of implementing concatenation +The Flang compiler has a general (but slow) means of implementing concatenation and a specialized (fast) option to optimize the most common case. ### General concatenation -In the most general case, the f18 compiler's generated code and +In the most general case, Flang's generated code and runtime support library represent the result as a deferred-length allocatable `CHARACTER` temporary scalar or array variable that is initialized as a zero-length array by `AllocatableInitCharacter()` diff --git a/flang/docs/DoConcurrent.md b/flang/docs/DoConcurrent.md index bd1008a..eba2656 100644 --- a/flang/docs/DoConcurrent.md +++ b/flang/docs/DoConcurrent.md @@ -280,7 +280,8 @@ Specifically, an easy means is required that stipulates that localization should apply at most only to the obvious cases of local non-pointer non-allocatable scalars. -In the LLVM Fortran compiler project (a/k/a "flang", "f18") we considered +In the LLVM Fortran compiler project (now known as "flang", previously also +known as "f18") we considered several solutions to this problem. 1. Add syntax (e.g., `DO PARALLEL` or `DO CONCURRENT() DEFAULT(PARALLEL)`) by which one can inform the compiler that it should localize only diff --git a/flang/docs/Extensions.md b/flang/docs/Extensions.md index 420b751..6d87209 100644 --- a/flang/docs/Extensions.md +++ b/flang/docs/Extensions.md @@ -84,7 +84,7 @@ end be "local identifiers" and should be distinct in the "inclusive scope" -- i.e., not scoped by `BLOCK` constructs. As most (but not all) compilers implement `BLOCK` scoping of construct - names, so does f18, with a portability warning. + names, so does Flang, with a portability warning. * 15.6.4 paragraph 2 prohibits an implicitly typed statement function from sharing the same name as a symbol in its scope's host, if it has one. @@ -153,7 +153,7 @@ end that a call to intrinsic module procedure `ieee_support_halting` with a constant argument has a compile time constant result in `constant expression` and `specification expression` contexts. In compilations - where this information is not known at compile time, f18 generates code + where this information is not known at compile time, Flang generates code to determine the absence or presence of this capability at runtime. A call to `ieee_support_halting` in contexts that the standard requires to be constant will generate a compilation error. `ieee_support_standard` @@ -366,7 +366,7 @@ end * The legacy extension intrinsic functions `IZEXT` and `JZEXT` are supported; `ZEXT` has different behavior with various older compilers, so it is not supported. -* f18 doesn't impose a limit on the number of continuation lines +* Flang doesn't impose a limit on the number of continuation lines allowed for a single statement. * When a type-bound procedure declaration statement has neither interface nor attributes, the "::" before the bindings is optional, even @@ -553,7 +553,7 @@ end * Fortran explicitly ignores type declaration statements when they attempt to type the name of a generic intrinsic function (8.2 p3). One can declare `CHARACTER::COS` and still get a real result - from `COS(3.14159)`, for example. f18 will complain when a + from `COS(3.14159)`, for example. Flang will complain when a generic intrinsic function's inferred result type does not match an explicit declaration. This message is a warning. @@ -570,7 +570,7 @@ end ## Standard features that might as well not be -* f18 supports designators with constant expressions, properly +* Flang supports designators with constant expressions, properly constrained, as initial data targets for data pointers in initializers of variable and component declarations and in `DATA` statements; e.g., `REAL, POINTER :: P => T(1:10:2)`. @@ -587,8 +587,8 @@ end * The standard doesn't explicitly require that a named constant that appears as part of a complex-literal-constant be a scalar, but most compilers emit an error when an array appears. - f18 supports them with a portability warning. -* f18 does not enforce a blanket prohibition against generic + Flang supports them with a portability warning. +* Flang does not enforce a blanket prohibition against generic interfaces containing a mixture of functions and subroutines. We allow both to appear, unlike several other Fortran compilers. This is especially desirable when two generics of the same @@ -655,7 +655,7 @@ end treat them as references to implicitly typed local variables, and load uninitialized values. - In f18, we chose to emit an error message for this case since the standard + In Flang, we chose to emit an error message for this case since the standard is unclear, the usage is not portable, and the issue can be easily resolved by adding a declaration. @@ -686,7 +686,7 @@ end * When a `DATA` statement in a `BLOCK` construct could be construed as either initializing a host-associated object or declaring a new local - initialized object, f18 interprets the standard's classification of + initialized object, Flang interprets the standard's classification of a `DATA` statement as being a "declaration" rather than a "specification" construct, and notes that the `BLOCK` construct is defined as localizing names that have specifications in the `BLOCK` construct. @@ -703,7 +703,7 @@ end subroutine Other Fortran compilers disagree with each other in their interpretations of this example. The precedent among the most commonly used compilers - agrees with f18's interpretation: a `DATA` statement without any other + agrees with Flang's interpretation: a `DATA` statement without any other specification of the name refers to the host-associated object. * Many Fortran compilers allow a non-generic procedure to be `USE`-associated @@ -729,7 +729,7 @@ module m2 end module ``` - This case elicits a warning from f18, as it should not be treated + This case elicits a warning from Flang, as it should not be treated any differently than the same case with the non-generic procedure of the same name being defined in the same scope rather than being `USE`-associated into it, which is explicitly non-conforming in the @@ -747,7 +747,7 @@ end module symbols, much less appear in specification inquiries, and there are application codes that expect exterior symbols whose names match components to be visible in a derived-type definition's default initialization - expressions, and so f18 follows that precedent. + expressions, and so Flang follows that precedent. * 19.3.1p1 "Within its scope, a local identifier of an entity of class (1) or class (4) shall not be the same as a global identifier used in that scope..." @@ -769,17 +769,17 @@ end module left-hand side for a pointer assignment statement, and we emit a portability warning when it is not. -* F18 allows a `USE` statement to reference a module that is defined later +* Flang allows a `USE` statement to reference a module that is defined later in the same compilation unit, so long as mutual dependencies do not form a cycle. This feature forestalls any risk of such a `USE` statement reading an obsolete module file from a previous compilation and then overwriting that file later. -* F18 allows `OPTIONAL` dummy arguments to interoperable procedures +* Flang allows `OPTIONAL` dummy arguments to interoperable procedures unless they are `VALUE` (C865). -* F18 processes the `NAMELIST` group declarations in a scope after it +* Flang processes the `NAMELIST` group declarations in a scope after it has resolved all of the names in that scope. This means that names that appear before their local declarations do not resolve to host associated objects and do not elicit errors about improper redeclarations @@ -862,11 +862,11 @@ print *, [(j,j=1,10)] * The Fortran standard doesn't mention integer overflow explicitly. In many cases, however, integer overflow makes programs non-conforming. - F18 follows other widely-used Fortran compilers. Specifically, f18 assumes + Flang follows other widely-used Fortran compilers. Specifically, Flang assumes integer overflow never occurs in address calculations and increment of do-variable unless the option `-fwrapv` is enabled. -* Two new ieee_round_type values were added in f18 beyond the four values +* Two new ieee_round_type values were added in Flang beyond the four values defined in f03 and f08: ieee_away and ieee_other. Contemporary hardware typically does not have support for these rounding modes; ieee_support_rounding calls for these values return false. diff --git a/flang/docs/FortranForCProgrammers.md b/flang/docs/FortranForCProgrammers.md index 135e6b7..9023fdc 100644 --- a/flang/docs/FortranForCProgrammers.md +++ b/flang/docs/FortranForCProgrammers.md @@ -304,7 +304,7 @@ Preprocessing behavior varies across implementations and one should not depend o much portability. Preprocessing is typically requested by the use of a capitalized filename suffix (e.g., "foo.F90") or a compiler command line option. -(Since the F18 compiler always runs its built-in preprocessing stage, +(Since Flang always runs its built-in preprocessing stage, no special option or filename suffix is required.) ## "Object Oriented" Programming diff --git a/flang/docs/FortranIR.md b/flang/docs/FortranIR.md index f9f8f64..7f3c7b2 100644 --- a/flang/docs/FortranIR.md +++ b/flang/docs/FortranIR.md @@ -171,7 +171,7 @@ FIR is intentionally similar to SIL from the statement level up to the level of Program, procedure, region, and basic block all leverage code from LLVM, in much the same way as SIL. These data structures have significant investment and engineering behind their use in compilers, and it makes sense to leverage that work. * Pro: Uses LLVM data structures, pervasive in compiler projects such as LLVM, SIL, etc. -* Pro: Get used to seeing and using LLVM, as f18 aims to be an LLVM project +* Pro: Get used to seeing and using LLVM, as Flang aims to be an LLVM project * Con: Uses LLVM data structures, which the project has been avoiding #### Alternative: C++ Standard Template Library diff --git a/flang/docs/GettingInvolved.md b/flang/docs/GettingInvolved.md index 79af788..2d28342 100644 --- a/flang/docs/GettingInvolved.md +++ b/flang/docs/GettingInvolved.md @@ -41,7 +41,7 @@ Contributions to Flang are done using GitHub Pull Requests and follow the ### Flang Slack Workspace - There is a Slack workspace dedicated to Flang. -- There are a number of topic-oriented channels available (e.g., #driver, #f18-semantics, #fir). +- There are a number of topic-oriented channels available (e.g., #driver, #fir). - Add yourself via the *[invitation link](https://join.slack.com/t/flang-compiler/shared_invite/zt-2pcn51lh-VrRQL_YUOkxA_1CEfMGQhw "title")* ## Calls diff --git a/flang/docs/Intrinsics.md b/flang/docs/Intrinsics.md index 34b6559..bfda5f3 100644 --- a/flang/docs/Intrinsics.md +++ b/flang/docs/Intrinsics.md @@ -19,7 +19,7 @@ of functions or subroutines with similar interfaces as an aid to comprehension beyond that which might be gained from the standard's alphabetical list. -A brief status of intrinsic procedure support in f18 is also given at the end. +A brief status of intrinsic procedure support in Flang is also given at the end. Few procedures are actually described here apart from their interfaces; see the Fortran 2018 standard (section 16) for the complete story. @@ -733,20 +733,20 @@ In case the invocation would be an error if the procedure were the intrinsic leaves two choices to the compiler: emit an error about the intrinsic invocation, or consider this is an external procedure and emit no error. -f18 will always consider this case to be the intrinsic and emit errors, unless the procedure +Flang will always consider this case to be the intrinsic and emit errors, unless the procedure is used as a function (resp. subroutine) and the intrinsic is a subroutine (resp. function). The table below gives some examples of decisions made by Fortran compilers in such case. | What is ACOS ? | Bad intrinsic call | External with warning | External no warning | Other error | | --- | --- | --- | --- | --- | -| `print*, ACOS()` | gfortran, nag, xlf, f18 | ifort | nvfortran | | -| `print*, ACOS(I)` | gfortran, nag, xlf, f18 | ifort | nvfortran | | -| `print*, ACOS(X=I)` | gfortran, nag, xlf, f18 | ifort | | nvfortran (keyword on implicit extrenal )| -| `print*, ACOS(X, X)` | gfortran, nag, xlf, f18 | ifort | nvfortran | | -| `CALL ACOS(X)` | | | gfortran, nag, xlf, nvfortran, ifort, f18 | | +| `print*, ACOS()` | gfortran, nag, xlf, flang | ifort | nvfortran | | +| `print*, ACOS(I)` | gfortran, nag, xlf, flang | ifort | nvfortran | | +| `print*, ACOS(X=I)` | gfortran, nag, xlf, flang | ifort | | nvfortran (keyword on implicit extrenal )| +| `print*, ACOS(X, X)` | gfortran, nag, xlf, flang | ifort | nvfortran | | +| `CALL ACOS(X)` | | | gfortran, nag, xlf, nvfortran, ifort, flang | | -The rationale for f18 behavior is that when referring to a procedure with an +The rationale for Flang behavior is that when referring to a procedure with an argument number or type that does not match the intrinsic specification, it seems safer to block the rather likely case where the user is using the intrinsic the wrong way. In case the user wanted to refer to an external function, he can add an explicit EXTERNAL @@ -759,13 +759,13 @@ Also note that in general, the standard gives the compiler the right to consider any procedure that is not explicitly external as a non standard intrinsic (section 4.2 point 4). So it is highly advised for the programmer to use EXTERNAL statements to prevent any ambiguity. -## Intrinsic Procedure Support in f18 -This section gives an overview of the support inside f18 libraries for the +## Intrinsic Procedure Support in Flang +This section gives an overview of the support inside Flang libraries for the intrinsic procedures listed above. -It may be outdated, refer to f18 code base for the actual support status. +It may be outdated, refer to Flang code base for the actual support status. ### Semantic Analysis -F18 semantic expression analysis phase detects intrinsic procedure references, +Flang semantic expression analysis phase detects intrinsic procedure references, validates the argument types and deduces the return types. This phase currently supports all the intrinsic procedures listed above but the ones in the table below. @@ -789,17 +789,17 @@ Constant Expressions may be used to define kind arguments. Therefore, the semant expression analysis phase must be able to fold references to intrinsic functions listed in section 10.1.12. -F18 intrinsic function folding is either performed by implementations directly -operating on f18 scalar types or by using host runtime functions and -host hardware types. F18 supports folding elemental intrinsic functions over +Flang intrinsic function folding is either performed by implementations directly +operating on Flang scalar types or by using host runtime functions and +host hardware types. Flang supports folding elemental intrinsic functions over arrays when an implementation is provided for the scalars (regardless of whether it is using host hardware types or not). The status of intrinsic function folding support is given in the sub-sections below. #### Intrinsic Functions with Host Independent Folding Support -Implementations using f18 scalar types enables folding intrinsic functions -on any host and with any possible type kind supported by f18. The intrinsic functions -listed below are folded using host independent implementations. +Implementations using Flang scalar types enables folding intrinsic functions +on any host and with any possible type kind supported by Flang. The intrinsic +functions listed below are folded using host independent implementations. | Return Type | Intrinsic Functions with Host Independent Folding Support| | --- | --- | @@ -810,12 +810,12 @@ listed below are folded using host independent implementations. #### Intrinsic Functions with Host Dependent Folding Support Implementations using the host runtime may not be available for all supported -f18 types depending on the host hardware types and the libraries available on the host. +Flang types depending on the hardware type of the host and the libraries available on it. The actual support on a host depends on what the host hardware types are. The list below gives the functions that are folded using host runtime and the related C/C++ types. -F18 automatically detects if these types match an f18 scalar type. If so, -folding of the intrinsic functions will be possible for the related f18 scalar type, -otherwise an error message will be produced by f18 when attempting to fold related intrinsic functions. +Flang automatically detects if these types match an Flang scalar type. If so, +folding of the intrinsic functions will be possible for the related Flang scalar type, +otherwise an error message will be produced by Flang when attempting to fold related intrinsic functions. | C/C++ Host Type | Intrinsic Functions with Host Standard C++ Library Based Folding Support | | --- | --- | @@ -823,17 +823,17 @@ otherwise an error message will be produced by f18 when attempting to fold relat | std::complex for float, double and long double| ACOS, ACOSH, ASIN, ASINH, ATAN, ATANH, COS, COSH, EXP, LOG, SIN, SINH, SQRT, TAN, TANH | On top of the default usage of C++ standard library functions for folding described -in the table above, it is possible to compile f18 evaluate library with +in the table above, it is possible to compile Flang evaluate library with [libpgmath](https://github.com/flang-compiler/flang/tree/master/runtime/libpgmath) so that it can be used for folding. To do so, one must have a compiled version of the libpgmath library available on the host and add -`-DLIBPGMATH_DIR=<path to the compiled shared libpgmath library>` to the f18 cmake command. +`-DLIBPGMATH_DIR=<path to the compiled shared libpgmath library>` to the Flang cmake command. Libpgmath comes with real and complex functions that replace C++ standard library float and double functions to fold all the intrinsic functions listed in the table above. -It has no long double versions. If the host long double matches an f18 scalar type, +It has no long double versions. If the host long double matches a Flang scalar type, C++ standard library functions will still be used for folding expressions with this scalar type. -Libpgmath adds the possibility to fold the following functions for f18 real scalar +Libpgmath adds the possibility to fold the following functions for Flang's real scalar types related to host float and double types. | C/C++ Host Type | Additional Intrinsic Function Folding Support with Libpgmath (Optional) | @@ -841,10 +841,10 @@ types related to host float and double types. |float and double| BESSEL_J0, BESSEL_J1, BESSEL_JN (elemental only), BESSEL_Y0, BESSEL_Y1, BESSEL_Yn (elemental only), DERFC_SCALED, ERFC_SCALED, QERFC_SCALED | Libpgmath comes in three variants (precise, relaxed and fast). So far, only the -precise version is used for intrinsic function folding in f18. It guarantees the greatest numerical precision. +precise version is used for intrinsic function folding in Flang. It guarantees the greatest numerical precision. ### Intrinsic Functions with Missing Folding Support -The following intrinsic functions are allowed in constant expressions but f18 +The following intrinsic functions are allowed in constant expressions but Flang is not yet able to fold them. Note that there might be constraints on the arguments so that these intrinsics can be used in constant expressions (see section 10.1.12 of Fortran 2018 standard). @@ -1133,8 +1133,8 @@ end program rename_proc - **Standard:** GNU extension - **Class:** function - **Syntax:** result = `SECNDS(refTime)` -- **Arguments:** - +- **Arguments:** + | ARGUMENT | INTENT | TYPE | KIND | Description | |-----------|--------|---------------|-------------------------|------------------------------------------| | `refTime` | `IN` | `REAL, scalar`| REAL(KIND=4), required | Reference time in seconds since midnight | @@ -1157,16 +1157,16 @@ END PROGRAM example_secnds since midnight minus a user-supplied reference time `refTime`. Uses `REAL(KIND=8)` for higher precision. #### Usage and Info -- **Standard:** PGI extension -- **Class:** function -- **Syntax:** result = `DSECNDS(refTime)` -- **Arguments:** +- **Standard:** PGI extension +- **Class:** function +- **Syntax:** result = `DSECNDS(refTime)` +- **Arguments:** | ARGUMENT | INTENT | TYPE | KIND | Description | |-----------|--------|---------------|-------------------------|------------------------------------------| | `refTime` | `IN` | `REAL, scalar`| REAL(KIND=8), required | Reference time in seconds since midnight | -- **Return Value:** REAL(KIND=8), scalar — seconds elapsed since `refTime`. +- **Return Value:** REAL(KIND=8), scalar — seconds elapsed since `refTime`. - **Purity:** Impure #### Example |