path: root/gcc/f/NEWS

*Note:* This file is automatically generated from the files
`news0.texi' and `news.texi'.  `NEWS' is *not* a source file, although
it is normally included within source distributions.

   This file lists news about the GCC-2.95 version (and some other
versions) of the GNU Fortran compiler.  Copyright (C) 1995-1999 Free
Software Foundation, Inc.  You may copy, distribute, and modify it
freely as long as you preserve this copyright notice and permission
notice.

News About GNU Fortran
**********************

   Changes made to recent versions of GNU Fortran are listed below,
with the most recent version first.

   The changes are generally listed in order:

  1. Code-generation and run-time-library bug-fixes

  2. Compiler and run-time-library crashes involving valid code that
     have been fixed

  3. New features

  4. Fixes and enhancements to existing features

  5. New diagnostics

  6. Internal improvements

  7. Miscellany

   This order is not strict--for example, some items involve a
combination of these elements.

   Note that two variants of `g77' are tracked below.  The `egcs'
variant is described vis-a-vis previous versions of `egcs' and/or an
official FSF version, as appropriate.

   Therefore, `egcs' versions sometimes have multiple listings to help
clarify how they differ from other versions, though this can make
getting a complete picture of what a particular `egcs' version contains
somewhat more difficult.

   *Warning:* The information below is still under development, and
might not accurately reflect the `g77' code base of which it is a part.
Efforts are made to keep it somewhat up-to-date, but they are
particularly concentrated on any version of this information that is
distributed as part of a *released* `g77'.

   In particular, while this information is intended to apply to the
GCC-2.95 version of `g77', only an official *release* of that version
is expected to contain documentation that is most consistent with the
`g77' product in that version.

   Nevertheless, information on *previous* releases of `g77', below, is
likely to be more up-to-date and accurate than the equivalent
information that accompanied those releases, assuming the last-updated
date of the information below is later than the dates of those releases.

   That's due to attempts to keep this development version of news
about previous `g77' versions up-to-date.

   An online, "live" version of this document (derived directly from
the mainline, development version of `g77' within `egcs') is available
at `http://www.gnu.org/software/gcc/onlinedocs/g77_news.html'.

   The following information was last updated on 1999-07-08:

In 0.5.25, `GCC' 2.95 (`EGCS' 1.2) versus `EGCS' 1.1.2:
=======================================================

  1. `g77' no longer generates bad code for assignments, or other
     conversions, of `REAL' or `COMPLEX' constant expressions to type
     `INTEGER(KIND=2)' (often referred to as `INTEGER*8').

     For example, `INTEGER*8 J; J = 4E10' now works as documented.

  2. `g77' no longer truncates `INTEGER(KIND=2)' (usually `INTEGER*8')
     subscript expressions when evaluating array references on systems
     with pointers widers than `INTEGER(KIND=1)' (such as Alphas).

  3. `g77' no longer generates bad code for an assignment to a
     `COMPLEX' variable or array that partially overlaps one or more of
     the sources of the same assignment (a very rare construction).  It
     now assigns through a temporary, in cases where such partial
     overlap is deemed possible.

  4. `libg2c' (`libf2c') no longer loses track of the file being worked
     on during a `BACKSPACE' operation.

  5. `libg2c' (`libf2c') fixes a bug whereby input to a `NAMELIST' read
     involving a repeat count, such as `K(5)=10*3', was not properly
     handled by `libf2c'.  The first item was written to `K(5)', but
     the remaining nine were written elsewhere (still within the array),
     not necessarily starting at `K(6)'.

  6. Automatic arrays now seem to be working on HP-UX systems.

  7. The `Date' intrinsic now returns the correct result on big-endian
     systems.

  8. Fix `g77' so it no longer crashes when compiling I/O statements
     using keywords that define `INTEGER' values, such as `IOSTAT=J',
     where J is other than default `INTEGER' (such as `INTEGER*2').
     Instead, it issues a diagnostic.

  9. Fix `g77' so it properly handles `DATA A/RPT*VAL/', where RPT is
     not default `INTEGER', such as `INTEGER*2', instead of producing a
     spurious diagnostic.  Also fix `DATA (A(I),I=1,N)', where `N' is
     not default `INTEGER' to work instead of crashing `g77'.

 10. The `-ax' option is now obeyed when compiling Fortran programs.
     (It is passed to the `f771' driver.)

   * The new `-fbounds-check' option causes `g77' to compile run-time
     bounds checks of array subscripts, as well as of substring start
     and end points.

   * `libg2c' now supports building as multilibbed library, which
     provides better support for systems that require options such as
     `-mieee' to work properly.

   * Source file names with the suffixes `.FOR' and `.FPP' now are
     recognized by `g77' as if they ended in `.for' and `.fpp',
     respectively.

   * The order of arguments to the *subroutine* forms of the `CTime',
     `DTime', `ETime', and `TtyNam' intrinsics has been swapped.  The
     argument serving as the returned value for the corresponding
     function forms now is the *second* argument, making these
     consistent with the other subroutine forms of `libU77' intrinsics.

   * `g77' now warns about a reference to an intrinsic that has an
     interface that is not Year 2000 (Y2K) compliant.  Also, `libg2c'
     has been changed to increase the likelihood of catching references
     to the implementations of these intrinsics using the `EXTERNAL'
     mechanism (which would avoid the new warnings).

 11. `g77' now warns about a reference to a function when the
     corresponding *subsequent* function program unit disagrees with
     the reference concerning the type of the function.

   * `-fno-emulate-complex' is now the default option.  This should
     result in improved performance of code that uses the `COMPLEX'
     data type.

   * The `-malign-double' option now reliably aligns *all*
     double-precision variables and arrays on Intel x86 targets.

 12. Even without the `-malign-double' option, `g77' reliably aligns
     local double-precision variables that are not in `EQUIVALENCE'
     areas and not `SAVE''d.

 13. `g77' now open-codes ("inlines") division of `COMPLEX' operands
     instead of generating a run-time call to the `libf2c' routines
     `c_div' or `z_div', unless the `-Os' option is specified.

   * `g77' no longer generates code to maintain `errno', a C-language
     concept, when performing operations such as the `SqRt' intrinsic.

 14. `g77' developers can temporarily use the `-fflatten-arrays' option
     to compare how the compiler handles code generation using C-like
     constructs as compared to the Fortran-like method constructs
     normally used.

 15. A substantial portion of the `g77' front end's code-generation
     component was rewritten.  It now generates code using facilities
     more robustly supported by the `gcc' back end.  One effect of this
     rewrite is that some codes no longer produce a spurious "label LAB
     used before containing binding contour" message.

   * Support for the `-fugly' option has been removed.

 16. Improve documentation and indexing, including information on Year
     2000 (Y2K) compliance, and providing more information on internals
     of the front end.

 17. Upgrade to `libf2c' as of 1999-05-10.

In 0.5.24 versus 0.5.23:
========================

   There is no `g77' version 0.5.24 at this time, or planned.  0.5.24
is the version number designated for bug fixes and, perhaps, some new
features added, to 0.5.23.  Version 0.5.23 requires `gcc' 2.8.1, as
0.5.24 was planned to require.

   Due to `EGCS' becoming `GCC' (which is now an acronym for "GNU
Compiler Collection"), and `EGCS' 1.2 becoming officially designated
`GCC' 2.95, there seems to be no need for an actual 0.5.24 release.

   To reduce the confusion already resulting from use of 0.5.24 to
designate `g77' versions within `EGCS' versions 1.0 and 1.1, as well as
in versions of `g77' documentation and notices during that period,
"mainline" `g77' version numbering resumes at 0.5.25 with `GCC' 2.95
(`EGCS' 1.2), skipping over 0.5.24 as a placeholder version number.

   To repeat, there is no `g77' 0.5.24, but there is now a 0.5.25.
Please remain calm and return to your keypunch units.

In `EGCS' 1.1.2 versus `EGCS' 1.1.1:
====================================

   * Fix the `IDate' intrinsic (VXT) (in `libg2c') so the returned year
     is in the documented, non-Y2K-compliant range of 0-99, instead of
     being returned as 100 in the year 2000.

   * Fix the `Date_and_Time' intrinsic (in `libg2c') to return the
     milliseconds value properly in VALUES(8).

   * Fix the `LStat' intrinsic (in `libg2c') to return device-ID
     information properly in SARRAY(7).

   * Improve documentation.

In `EGCS' 1.1.1 versus `EGCS' 1.1:
==================================

   * Fix `libg2c' so it performs an implicit `ENDFILE' operation (as
     appropriate) whenever a `REWIND' is done.

     (This bug was introduced in 0.5.23 and `egcs' 1.1 in `g77''s
     version of `libf2c'.)

   * Fix `libg2c' so it no longer crashes with a spurious diagnostic
     upon doing any I/O following a direct formatted write.

     (This bug was introduced in 0.5.23 and `egcs' 1.1 in `g77''s
     version of `libf2c'.)

   * Fix `g77' so it no longer crashes compiling references to the
     `Rand' intrinsic on some systems.

   * Fix `g77' portion of installation process so it works better on
     some systems (those with shells requiring `else true' clauses on
     `if' constructs for the completion code to be set properly).

In `EGCS' 1.1 versus `EGCS' 1.0.3:
==================================

 18. Fix bugs in the `libU77' intrinsic `HostNm' that wrote one byte
     beyond the end of its `CHARACTER' argument, and in the `libU77'
     intrinsics `GMTime' and `LTime' that overwrote their arguments.

 19. Assumed arrays with negative bounds (such as `REAL A(-1:*)') no
     longer elicit spurious diagnostics from `g77', even on systems
     with pointers having different sizes than integers.

     This bug is not known to have existed in any recent version of
     `gcc'.  It was introduced in an early release of `egcs'.

 20. Valid combinations of `EXTERNAL', passing that external as a dummy
     argument without explicitly giving it a type, and, in a subsequent
     program unit, referencing that external as an external function
     with a different type no longer crash `g77'.

 21. `CASE DEFAULT' no longer crashes `g77'.

 22. The `-Wunused' option no longer issues a spurious warning about
     the "master" procedure generated by `g77' for procedures
     containing `ENTRY' statements.

   * Support `FORMAT(I<EXPR>)' when EXPR is a compile-time constant
     `INTEGER' expression.

   * Fix `g77' `-g' option so procedures that use `ENTRY' can be
     stepped through, line by line, in `gdb'.

   * Allow any `REAL' argument to intrinsics `Second' and `CPU_Time'.

   * Use `tempnam', if available, to open scratch files (as in
     `OPEN(STATUS='SCRATCH')') so that the `TMPDIR' environment
     variable, if present, is used.

   * `g77''s version of `libf2c' separates out the setting of global
     state (such as command-line arguments and signal handling) from
     `main.o' into distinct, new library archive members.

     This should make it easier to write portable applications that
     have their own (non-Fortran) `main()' routine properly set up the
     `libf2c' environment, even when `libf2c' (now `libg2c') is a
     shared library.

 23. `g77' no longer installs the `f77' command and `f77.1' man page in
     the `/usr' or `/usr/local' heirarchy, even if the `f77-install-ok'
     file exists in the source or build directory.  See the
     installation documentation for more information.

 24. `g77' no longer installs the `libf2c.a' library and `f2c.h'
     include file in the `/usr' or `/usr/local' heirarchy, even if the
     `f2c-install-ok' or `f2c-exists-ok' files exist in the source or
     build directory.  See the installation documentation for more
     information.

 25. The `libf2c.a' library produced by `g77' has been renamed to
     `libg2c.a'.  It is installed only in the `gcc' "private" directory
     heirarchy, `gcc-lib'.  This allows system administrators and users
     to choose which version of the `libf2c' library from `netlib' they
     wish to use on a case-by-case basis.  See the installation
     documentation for more information.

 26. The `f2c.h' include (header) file produced by `g77' has been
     renamed to `g2c.h'.  It is installed only in the `gcc' "private"
     directory heirarchy, `gcc-lib'.  This allows system administrators
     and users to choose which version of the include file from
     `netlib' they wish to use on a case-by-case basis.  See the
     installation documentation for more information.

   * The `g77' command now expects the run-time library to be named
     `libg2c.a' instead of `libf2c.a', to ensure that a version other
     than the one built and installed as part of the same `g77' version
     is picked up.

 27. During the configuration and build process, `g77' creates
     subdirectories it needs only as it needs them.  Other cleaning up
     of the configuration and build process has been performed as well.

 28. `install-info' now used to update the directory of Info
     documentation to contain an entry for `g77' (during installation).

   * Some diagnostics have been changed from warnings to errors, to
     prevent inadvertent use of the resulting, probably buggy, programs.
     These mostly include diagnostics about use of unsupported features
     in the `OPEN', `INQUIRE', `READ', and `WRITE' statements, and
     about truncations of various sorts of constants.

 29. Improve compilation of `FORMAT' expressions so that a null byte is
     appended to the last operand if it is a constant.  This provides a
     cleaner run-time diagnostic as provided by `libf2c' for statements
     like `PRINT '(I1', 42'.

 30. Improve documentation and indexing.

 31. The upgrade to `libf2c' as of 1998-06-18 should fix a variety of
     problems, including those involving some uses of the `T' format
     specifier, and perhaps some build (porting) problems as well.

In `EGCS' 1.1 versus `g77' 0.5.23:
==================================

 32. Fix a code-generation bug that afflicted Intel x86 targets when
     `-O2' was specified compiling, for example, an old version of the
     `DNRM2' routine.

     The x87 coprocessor stack was being mismanaged in cases involving
     assigned `GOTO' and `ASSIGN'.

 33. `g77' no longer produces incorrect code and initial values for
     `EQUIVALENCE' and `COMMON' aggregates that, due to "unnatural"
     ordering of members vis-a-vis their types, require initial padding.

 34. Fix `g77' crash compiling code containing the construct
     `CMPLX(0.)' or similar.

 35. `g77' no longer crashes when compiling code containing
     specification statements such as `INTEGER(KIND=7) PTR'.

 36. `g77' no longer crashes when compiling code such as `J = SIGNAL(1,
     2)'.

   * `g77' now treats `%LOC(EXPR)' and `LOC(EXPR)' as "ordinary"
     expressions when they are used as arguments in procedure calls.
     This change applies only to global (filewide) analysis, making it
     consistent with how `g77' actually generates code for these cases.

     Previously, `g77' treated these expressions as denoting special
     "pointer" arguments for the purposes of filewide analysis.

 37. Fix `g77' crash (or apparently infinite run-time) when compiling
     certain complicated expressions involving `COMPLEX' arithmetic
     (especially multiplication).

   * Align static double-precision variables and arrays on Intel x86
     targets regardless of whether `-malign-double' is specified.

     Generally, this affects only local variables and arrays having the
     `SAVE' attribute or given initial values via `DATA'.

   * The `g77' driver now ensures that `-lg2c' is specified in the link
     phase prior to any occurrence of `-lm'.  This prevents
     accidentally linking to a routine in the SunOS4 `-lm' library when
     the generated code wants to link to the one in `libf2c' (`libg2c').

   * `g77' emits more debugging information when `-g' is used.

     This new information allows, for example, `which __g77_length_a'
     to be used in `gdb' to determine the type of the phantom length
     argument supplied with `CHARACTER' variables.

     This information pertains to internally-generated type, variable,
     and other information, not to the longstanding deficiencies
     vis-a-vis `COMMON' and `EQUIVALENCE'.

   * The F90 `Date_and_Time' intrinsic now is supported.

   * The F90 `System_Clock' intrinsic allows the optional arguments
     (except for the `Count' argument) to be omitted.

 38. Upgrade to `libf2c' as of 1998-06-18.

 39. Improve documentation and indexing.

In previous versions:
=====================

   Information on previous versions is not provided in this
`egcs/gcc/f/NEWS' file, to keep it short.  See `egcs/gcc/f/news.texi',
or any of its other derivations (Info, HTML, dvi forms) for such
information.