GNU Info
(g77-300.info)News
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. Note that all such variants are
obsolete _as of July 1999_ - the information is retained here only for
its historical value.
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.
For information on bugs in the GCC-3.0 version of `g77', see Note:
Known Bugs In GNU Fortran.
An online, "live" version of this document (derived directly from
the mainline, development version of `g77' within `gcc') is available at
`http://www.gnu.org/software/gcc/onlinedocs/g77_news.html'.
The following information was last updated on 2001-06-03:
In 0.5.26, `GCC' 3.0 versus `GCC' 2.95:
=======================================
* When a REWIND was issued after a WRITE statement on an unformatted
file, the implicit truncation was performed by copying the
truncated file to /tmp and copying the result back. This has been
fixed by using the `ftruncate' OS function. Thanks go to the
GAMESS developers for bringing this to our attention.
* Using options `-g', `-ggdb' or `-gdwarf[-2]' (where appropriate
for your target) now also enables debugging information for COMMON
BLOCK and EQUIVALENCE items to be emitted. Thanks go to Andrew
Vaught (<andy@xena.eas.asu.edu>) and George Helffrich
(<george@geology.bristol.ac.uk>) for fixing this longstanding
problem.
* It is not necessary anymore to use the option `-femulate-complex'
to compile Fortran code using COMPLEX arithmetic, even on 64-bit
machines (like the Alpha). This will improve code generation.
* INTRINSIC arithmetic functions are now treated as routines that do
not depend on anything but their argument(s). This enables
further instruction scheduling, because it is known that they
cannot read or modify arbitrary locations.
* Upgrade to `libf2c' as of 2000-12-05.
This fixes a bug where a namelist containing initialization of
LOGICAL items and a variable starting with T or F would be read
incorrectly.
* The `TtyNam' intrinsics now set NAME to all spaces (at run time)
if the system has no `ttyname' implementation available.
* Upgrade to `libf2c' as of 1999-06-28.
This 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)'.
In 0.5.25, `GCC' 2.95 (`EGCS' 1.2) versus `EGCS' 1.1.2:
=======================================================
* `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.
* `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).
* `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.
* `libg2c' (`libf2c') no longer loses track of the file being worked
on during a `BACKSPACE' operation.
* `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)'.
* Automatic arrays now seem to be working on HP-UX systems.
* The `Date' intrinsic now returns the correct result on big-endian
systems.
* 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.
* 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'.
* 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).
Note: Year 2000 (Y2K) Problems, for more information.
* `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.
* Even without the `-malign-double' option, `g77' reliably aligns
local double-precision variables that are not in `EQUIVALENCE'
areas and not `SAVE''d.
* `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.
* `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.
* 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.
* Improve documentation and indexing, including information on Year
2000 (Y2K) compliance, and providing more information on internals
of the front end.
* 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.
Note: IDate Intrinsic (VXT), for more information.
* 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:
==================================
* 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.
* 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'.
* 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'.
* `CASE DEFAULT' no longer crashes `g77'.
* 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.
* `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.
* `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.
* 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.
* 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.
* 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.
* `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.
* 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'.
* Improve documentation and indexing.
* 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:
==================================
* 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'.
* `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.
* Fix `g77' crash compiling code containing the construct
`CMPLX(0.)' or similar.
* `g77' no longer crashes when compiling code containing
specification statements such as `INTEGER(KIND=7) PTR'.
* `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.
* 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.
* Upgrade to `libf2c' as of 1998-06-18.
* Improve documentation and indexing.
In 0.5.23 versus 0.5.22:
========================
* This release contains several regressions against version 0.5.22
of `g77', due to using the "vanilla" `gcc' back end instead of
patching it to fix a few bugs and improve performance in a few
cases.
Features that have been dropped from this version of `g77' due to
their being implemented via `g77'-specific patches to the `gcc'
back end in previous releases include:
- Support for `__restrict__' keyword, the options
`-fargument-alias', `-fargument-noalias', and
`-fargument-noalias-global', and the corresponding
alias-analysis code.
(`egcs' has the alias-analysis code, but not the
`__restrict__' keyword. `egcs' `g77' users benefit from the
alias-analysis code despite the lack of the `__restrict__'
keyword, which is a C-language construct.)
- Support for the GNU compiler options `-fmove-all-movables',
`-freduce-all-givs', and `-frerun-loop-opt'.
(`egcs' supports these options. `g77' users of `egcs'
benefit from them even if they are not explicitly specified,
because the defaults are optimized for `g77' users.)
- Support for the `-W' option warning about integer division by
zero.
- The Intel x86-specific option `-malign-double' applying to
stack-allocated data as well as statically-allocate data.
Note that the `gcc/f/gbe/' subdirectory has been removed from this
distribution as a result of `g77' no longer including patches for
the `gcc' back end.
* 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.
* Support `gcc' version 2.8, and remove support for prior versions
of `gcc'.
* Remove support for the `--driver' option, as `g77' now does all
the driving, just like `gcc'.
* `CASE DEFAULT' no longer crashes `g77'.
* 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'.
* `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.
* `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.
* 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.
* 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.
* The `-Wunused' option no longer issues a spurious warning about
the "master" procedure generated by `g77' for procedures
containing `ENTRY' statements.
* `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.
* During the configuration and build process, `g77' creates
subdirectories it needs only as it needs them, thus avoiding
unnecessary creation of, for example, `stage1/f/runtime' when
doing a non-bootstrap build. Other cleaning up of the
configuration and build process has been performed as well.
* `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.
* Improve documentation and indexing.
* Upgrade to `libf2c' as of 1998-04-20.
This 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 0.5.22 versus 0.5.21:
========================
* Fix code generation for iterative `DO' loops that have one or more
references to the iteration variable, or to aliases of it, in
their control expressions. For example, `DO 10 J=2,J' now is
compiled correctly.
* 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'.
* Fix `DTime' intrinsic so as not to truncate results to integer
values (on some systems).
* Fix `Signal' intrinsic so it offers portable support for 64-bit
systems (such as Digital Alphas running GNU/Linux).
* Fix run-time crash involving `NAMELIST' on 64-bit machines such as
Alphas.
* Fix `g77' version of `libf2c' so it no longer produces a spurious
`I/O recursion' diagnostic at run time when an I/O operation (such
as `READ *,I') is interrupted in a manner that causes the program
to be terminated via the `f_exit' routine (such as via `C-c').
* Fix `g77' crash triggered by `CASE' statement with an omitted
lower or upper bound.
* Fix `g77' crash compiling references to `CPU_Time' intrinsic.
* Fix `g77' crash (or apparently infinite run-time) when compiling
certain complicated expressions involving `COMPLEX' arithmetic
(especially multiplication).
* Fix `g77' crash on statements such as `PRINT *,
(REAL(Z(I)),I=1,2)', where `Z' is `DOUBLE COMPLEX'.
* Fix a `g++' crash.
* 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'.
* Fix a profiling-related bug in `gcc' back end for Intel x86
architecture.
* Allow any `REAL' argument to intrinsics `Second' and `CPU_Time'.
* Allow any numeric argument to intrinsics `Int2' and `Int8'.
* Use `tempnam', if available, to open scratch files (as in
`OPEN(STATUS='SCRATCH')') so that the `TMPDIR' environment
variable, if present, is used.
* Rename the `gcc' keyword `restrict' to `__restrict__', to avoid
rejecting valid, existing, C programs. Support for `restrict' is
now more like support for `complex'.
* Fix `-fpedantic' to not reject procedure invocations such as
`I=J()' and `CALL FOO()'.
* Fix `-fugly-comma' to affect invocations of only external
procedures. Restore rejection of gratuitous trailing omitted
arguments to intrinsics, as in `I=MAX(3,4,,)'.
* Fix compiler so it accepts `-fgnu-intrinsics-*' and
`-fbadu77-intrinsics-*' options.
* Improve diagnostic messages from `libf2c' so it is more likely
that the printing of the active format string is limited to the
string, with no trailing garbage being printed.
(Unlike `f2c', `g77' did not append a null byte to its compiled
form of every format string specified via a `FORMAT' statement.
However, `f2c' would exhibit the problem anyway for a statement
like `PRINT '(I)garbage', 1' by printing `(I)garbage' as the
format string.)
* 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'.
* Fix various crashes involving code with diagnosed errors.
* Fix cross-compilation bug when configuring `libf2c'.
* Improve diagnostics.
* Improve documentation and indexing.
* Upgrade to `libf2c' as of 1997-09-23. This fixes a formatted-I/O
bug that afflicted 64-bit systems with 32-bit integers (such as
Digital Alpha running GNU/Linux).
In `EGCS' 1.0.2 versus `EGCS' 1.0.1:
====================================
* Fix `g77' crash triggered by `CASE' statement with an omitted
lower or upper bound.
* Fix `g77' crash on statements such as `PRINT *,
(REAL(Z(I)),I=1,2)', where `Z' is `DOUBLE COMPLEX'.
* Fix `-fPIC' (such as compiling for ELF targets) on the Intel x86
architecture target so invalid assembler code is no longer
produced.
* Fix `-fpedantic' to not reject procedure invocations such as
`I=J()' and `CALL FOO()'.
* Fix `-fugly-comma' to affect invocations of only external
procedures. Restore rejection of gratuitous trailing omitted
arguments to intrinsics, as in `I=MAX(3,4,,)'.
* Fix compiler so it accepts `-fgnu-intrinsics-*' and
`-fbadu77-intrinsics-*' options.
In `EGCS' 1.0.1 versus `EGCS' 1.0:
==================================
* Fix run-time crash involving `NAMELIST' on 64-bit machines such as
Alphas.
In `EGCS' 1.0 versus `g77' 0.5.21:
==================================
* Version 1.0 of `egcs' contains several regressions against version
0.5.21 of `g77', due to using the "vanilla" `gcc' back end instead
of patching it to fix a few bugs and improve performance in a few
cases.
Features that have been dropped from this version of `g77' due to
their being implemented via `g77'-specific patches to the `gcc'
back end in previous releases include:
- Support for the C-language `restrict' keyword.
- Support for the `-W' option warning about integer division by
zero.
- The Intel x86-specific option `-malign-double' applying to
stack-allocated data as well as statically-allocate data.
Note that the `gcc/f/gbe/' subdirectory has been removed from this
distribution as a result of `g77' being fully integrated with the
`egcs' variant of the `gcc' back end.
* Fix code generation for iterative `DO' loops that have one or more
references to the iteration variable, or to aliases of it, in
their control expressions. For example, `DO 10 J=2,J' now is
compiled correctly.
* Fix `DTime' intrinsic so as not to truncate results to integer
values (on some systems).
* Some Fortran code, miscompiled by `g77' built on `gcc' version
2.8.1 on m68k-next-nextstep3 configurations when using the `-O2'
option, is now compiled correctly. It is believed that a C
function known to miscompile on that configuration when using the
`-O2 -funroll-loops' options also is now compiled correctly.
* Remove support for non-`egcs' versions of `gcc'.
* Remove support for the `--driver' option, as `g77' now does all
the driving, just like `gcc'.
* Allow any numeric argument to intrinsics `Int2' and `Int8'.
* Improve diagnostic messages from `libf2c' so it is more likely
that the printing of the active format string is limited to the
string, with no trailing garbage being printed.
(Unlike `f2c', `g77' did not append a null byte to its compiled
form of every format string specified via a `FORMAT' statement.
However, `f2c' would exhibit the problem anyway for a statement
like `PRINT '(I)garbage', 1' by printing `(I)garbage' as the
format string.)
* Upgrade to `libf2c' as of 1997-09-23. This fixes a formatted-I/O
bug that afflicted 64-bit systems with 32-bit integers (such as
Digital Alpha running GNU/Linux).
In 0.5.21:
==========
* Fix a code-generation bug introduced by 0.5.20 caused by loop
unrolling (by specifying `-funroll-loops' or similar). This bug
afflicted all code compiled by version 2.7.2.2.f.2 of `gcc' (C,
C++, Fortran, and so on).
* Fix a code-generation bug manifested when combining local
`EQUIVALENCE' with a `DATA' statement that follows the first
executable statement (or is treated as an executable-context
statement as a result of using the `-fpedantic' option).
* Fix a compiler crash that occured when an integer division by a
constant zero is detected. Instead, when the `-W' option is
specified, the `gcc' back end issues a warning about such a case.
This bug afflicted all code compiled by version 2.7.2.2.f.2 of
`gcc' (C, C++, Fortran, and so on).
* Fix a compiler crash that occurred in some cases of procedure
inlining. (Such cases became more frequent in 0.5.20.)
* Fix a compiler crash resulting from using `DATA' or similar to
initialize a `COMPLEX' variable or array to zero.
* Fix compiler crashes involving use of `AND', `OR', or `XOR'
intrinsics.
* Fix compiler bug triggered when using a `COMMON' or `EQUIVALENCE'
variable as the target of an `ASSIGN' or assigned-`GOTO' statement.
* Fix compiler crashes due to using the name of a some non-standard
intrinsics (such as `FTell' or `FPutC') as such and as the name of
a procedure or common block. Such dual use of a name in a program
is allowed by the standard.
* Place automatic arrays on the stack, even if `SAVE' or the
`-fno-automatic' option is in effect. This avoids a compiler
crash in some cases.
* The `-malign-double' option now reliably aligns `DOUBLE PRECISION'
optimally on Pentium and Pentium Pro architectures (586 and 686 in
`gcc').
* New option `-Wno-globals' disables warnings about "suspicious" use
of a name both as a global name and as the implicit name of an
intrinsic, and warnings about disagreements over the number or
natures of arguments passed to global procedures, or the natures
of the procedures themselves.
The default is to issue such warnings, which are new as of this
version of `g77'.
* New option `-fno-globals' disables diagnostics about potentially
fatal disagreements analysis problems, such as disagreements over
the number or natures of arguments passed to global procedures, or
the natures of those procedures themselves.
The default is to issue such diagnostics and flag the compilation
as unsuccessful. With this option, the diagnostics are issued as
warnings, or, if `-Wno-globals' is specified, are not issued at
all.
This option also disables inlining of global procedures, to avoid
compiler crashes resulting from coding errors that these
diagnostics normally would identify.
* Diagnose cases where a reference to a procedure disagrees with the
type of that procedure, or where disagreements about the number or
nature of arguments exist. This avoids a compiler crash.
* Fix parsing bug whereby `g77' rejected a second initialization
specification immediately following the first's closing `/' without
an intervening comma in a `DATA' statement, and the second
specification was an implied-DO list.
* Improve performance of the `gcc' back end so certain complicated
expressions involving `COMPLEX' arithmetic (especially
multiplication) don't appear to take forever to compile.
* Fix a couple of profiling-related bugs in `gcc' back end.
* Integrate GNU Ada's (GNAT's) changes to the back end, which
consist almost entirely of bug fixes. These fixes are circa
version 3.10p of GNAT.
* Include some other `gcc' fixes that seem useful in `g77''s version
of `gcc'. (See `gcc/ChangeLog' for details--compare it to that
file in the vanilla `gcc-2.7.2.3.tar.gz' distribution.)
* Fix `libU77' routines that accept file and other names to strip
trailing blanks from them, for consistency with other
implementations. Blanks may be forcibly appended to such names by
appending a single null character (`CHAR(0)') to the significant
trailing blanks.
* Fix `CHMOD' intrinsic to work with file names that have embedded
blanks, commas, and so on.
* Fix `SIGNAL' intrinsic so it accepts an optional third `Status'
argument.
* Fix `IDATE()' intrinsic subroutine (VXT form) so it accepts
arguments in the correct order. Documentation fixed accordingly,
and for `GMTIME()' and `LTIME()' as well.
* Make many changes to `libU77' intrinsics to support existing code
more directly.
Such changes include allowing both subroutine and function forms
of many routines, changing `MCLOCK()' and `TIME()' to return
`INTEGER(KIND=1)' values, introducing `MCLOCK8()' and `TIME8()' to
return `INTEGER(KIND=2)' values, and placing functions that are
intended to perform side effects in a new intrinsic group,
`badu77'.
* Improve `libU77' so it is more portable.
* Add options `-fbadu77-intrinsics-delete',
`-fbadu77-intrinsics-hide', and so on.
* Fix crashes involving diagnosed or invalid code.
* `g77' and `gcc' now do a somewhat better job detecting and
diagnosing arrays that are too large to handle before these cause
diagnostics during the assembler or linker phase, a compiler
crash, or generation of incorrect code.
* Make some fixes to alias analysis code.
* Add support for `restrict' keyword in `gcc' front end.
* Support `gcc' version 2.7.2.3 (modified by `g77' into version
2.7.2.3.f.1), and remove support for prior versions of `gcc'.
* Incorporate GNAT's patches to the `gcc' back end into `g77''s, so
GNAT users do not need to apply GNAT's patches to build both GNAT
and `g77' from the same source tree.
* Modify `make' rules and related code so that generation of Info
documentation doesn't require compilation using `gcc'. Now, any
ANSI C compiler should be adequate to produce the `g77'
documentation (in particular, the tables of intrinsics) from
scratch.
* Add `INT2' and `INT8' intrinsics.
* Add `CPU_TIME' intrinsic.
* Add `ALARM' intrinsic.
* `CTIME' intrinsic now accepts any `INTEGER' argument, not just
`INTEGER(KIND=2)'.
* Warn when explicit type declaration disagrees with the type of an
intrinsic invocation.
* Support `*f771' entry in `gcc' `specs' file.
* Fix typo in `make' rule `g77-cross', used only for cross-compiling.
* Fix `libf2c' build procedure to re-archive library if previous
attempt to archive was interrupted.
* Change `gcc' to unroll loops only during the last invocation (of
as many as two invocations) of loop optimization.
* Improve handling of `-fno-f2c' so that code that attempts to pass
an intrinsic as an actual argument, such as `CALL FOO(ABS)', is
rejected due to the fact that the run-time-library routine is,
effectively, compiled with `-ff2c' in effect.
* Fix `g77' driver to recognize `-fsyntax-only' as an option that
inhibits linking, just like `-c' or `-S', and to recognize and
properly handle the `-nostdlib', `-M', `-MM', `-nodefaultlibs',
and `-Xlinker' options.
* Upgrade to `libf2c' as of 1997-08-16.
* Modify `libf2c' to consistently and clearly diagnose recursive I/O
(at run time).
* `g77' driver now prints version information (such as produced by
`g77 -v') to `stderr' instead of `stdout'.
* The `.r' suffix now designates a Ratfor source file, to be
preprocessed via the `ratfor' command, available separately.
* Fix some aspects of how `gcc' determines what kind of system is
being configured and what kinds are supported. For example, GNU
Linux/Alpha ELF systems now are directly supported.
* Improve diagnostics.
* Improve documentation and indexing.
* Include all pertinent files for `libf2c' that come from
`netlib.bell-labs.com'; give any such files that aren't quite
accurate in `g77''s version of `libf2c' the suffix `.netlib'.
* Reserve `INTEGER(KIND=0)' for future use.
In 0.5.20:
==========
* The `-fno-typeless-boz' option is now the default.
This option specifies that non-decimal-radix constants using the
prefixed-radix form (such as `Z'1234'') are to be interpreted as
`INTEGER(KIND=1)' constants. Specify `-ftypeless-boz' to cause
such constants to be interpreted as typeless.
(Version 0.5.19 introduced `-fno-typeless-boz' and its inverse.)
Note: Options Controlling Fortran Dialect,
for information on the `-ftypeless-boz' option.
* Options `-ff90-intrinsics-enable' and `-fvxt-intrinsics-enable'
now are the defaults.
Some programs might use names that clash with intrinsic names
defined (and now enabled) by these options or by the new `libU77'
intrinsics. Users of such programs might need to compile them
differently (using, for example, `-ff90-intrinsics-disable') or,
better yet, insert appropriate `EXTERNAL' statements specifying
that these names are not intended to be names of intrinsics.
* The `ALWAYS_FLUSH' macro is no longer defined when building
`libf2c', which should result in improved I/O performance,
especially over NFS.
_Note:_ If you have code that depends on the behavior of `libf2c'
when built with `ALWAYS_FLUSH' defined, you will have to modify
`libf2c' accordingly before building it from this and future
versions of `g77'.
Note: Output Assumed To Flush, for more information.
* Dave Love's implementation of `libU77' has been added to the
version of `libf2c' distributed with and built as part of `g77'.
`g77' now knows about the routines in this library as intrinsics.
* New option `-fvxt' specifies that the source file is written in
VXT Fortran, instead of GNU Fortran.
Note: VXT Fortran, for more information on the constructs
recognized when the `-fvxt' option is specified.
* The `-fvxt-not-f90' option has been deleted, along with its
inverse, `-ff90-not-vxt'.
If you used one of these deleted options, you should re-read the
pertinent documentation to determine which options, if any, are
appropriate for compiling your code with this version of `g77'.
Note: Other Dialects, for more information.
* The `-fugly' option now issues a warning, as it likely will be
removed in a future version.
(Enabling all the `-fugly-*' options is unlikely to be feasible,
or sensible, in the future, so users should learn to specify only
those `-fugly-*' options they really need for a particular source
file.)
* The `-fugly-assumed' option, introduced in version 0.5.19, has
been changed to better accommodate old and new code.
Note: Ugly Assumed-Size Arrays, for more information.
* Make a number of fixes to the `g77' front end and the `gcc' back
end to better support Alpha (AXP) machines. This includes
providing at least one bug-fix to the `gcc' back end for Alphas.
* Related to supporting Alpha (AXP) machines, the `LOC()' intrinsic
and `%LOC()' construct now return values of `INTEGER(KIND=0)' type,
as defined by the GNU Fortran language.
This type is wide enough (holds the same number of bits) as the
character-pointer type on the machine.
On most machines, this won't make a difference, whereas, on Alphas
and other systems with 64-bit pointers, the `INTEGER(KIND=0)' type
is equivalent to `INTEGER(KIND=2)' (often referred to as
`INTEGER*8') instead of the more common `INTEGER(KIND=1)' (often
referred to as `INTEGER*4').
* Emulate `COMPLEX' arithmetic in the `g77' front end, to avoid bugs
in `complex' support in the `gcc' back end. New option
`-fno-emulate-complex' causes `g77' to revert the 0.5.19 behavior.
* Fix bug whereby `REAL A(1)', for example, caused a compiler crash
if `-fugly-assumed' was in effect and A was a local (automatic)
array. That case is no longer affected by the new handling of
`-fugly-assumed'.
* Fix `g77' command driver so that `g77 -o foo.f' no longer deletes
`foo.f' before issuing other diagnostics, and so the `-x' option
is properly handled.
* Enable inlining of subroutines and functions by the `gcc' back end.
This works as it does for `gcc' itself--program units may be
inlined for invocations that follow them in the same program unit,
as long as the appropriate compile-time options are specified.
* Dummy arguments are no longer assumed to potentially alias
(overlap) other dummy arguments or `COMMON' areas when any of
these are defined (assigned to) by Fortran code.
This can result in faster and/or smaller programs when compiling
with optimization enabled, though on some systems this effect is
observed only when `-fforce-addr' also is specified.
New options `-falias-check', `-fargument-alias',
`-fargument-noalias', and `-fno-argument-noalias-global' control
the way `g77' handles potential aliasing.
Note: Aliasing Assumed To Work, for detailed information on why
the new defaults might result in some programs no longer working
the way they did when compiled by previous versions of `g77'.
* The `CONJG()' and `DCONJG()' intrinsics now are compiled in-line.
* The bug-fix for 0.5.19.1 has been re-done. The `g77' compiler has
been changed back to assume `libf2c' has no aliasing problems in
its implementations of the `COMPLEX' (and `DOUBLE COMPLEX')
intrinsics. The `libf2c' has been changed to have no such
problems.
As a result, 0.5.20 is expected to offer improved performance over
0.5.19.1, perhaps as good as 0.5.19 in most or all cases, due to
this change alone.
_Note:_ This change requires version 0.5.20 of `libf2c', at least,
when linking code produced by any versions of `g77' other than
0.5.19.1. Use `g77 -v' to determine the version numbers of the
`libF77', `libI77', and `libU77' components of the `libf2c'
library. (If these version numbers are not printed--in
particular, if the linker complains about unresolved references to
names like `g77__fvers__'--that strongly suggests your
installation has an obsolete version of `libf2c'.)
* New option `-fugly-assign' specifies that the same memory
locations are to be used to hold the values assigned by both
statements `I = 3' and `ASSIGN 10 TO I', for example. (Normally,
`g77' uses a separate memory location to hold assigned statement
labels.)
Note: Ugly Assigned Labels, for more information.
* `FORMAT' and `ENTRY' statements now are allowed to precede
`IMPLICIT NONE' statements.
* Produce diagnostic for unsupported `SELECT CASE' on `CHARACTER'
type, instead of crashing, at compile time.
* Fix crashes involving diagnosed or invalid code.
* Change approach to building `libf2c' archive (`libf2c.a') so that
members are added to it only when truly necessary, so the user
that installs an already-built `g77' doesn't need to have write
access to the build tree (whereas the user doing the build might
not have access to install new software on the system).
* Support `gcc' version 2.7.2.2 (modified by `g77' into version
2.7.2.2.f.2), and remove support for prior versions of `gcc'.
* Upgrade to `libf2c' as of 1997-02-08, and fix up some of the build
procedures.
* Improve general build procedures for `g77', fixing minor bugs
(such as deletion of any file named `f771' in the parent directory
of `gcc/').
* Enable full support of `INTEGER(KIND=2)' (often referred to as
`INTEGER*8') available in `libf2c' and `f2c.h' so that `f2c' users
may make full use of its features via the `g77' version of `f2c.h'
and the `INTEGER(KIND=2)' support routines in the `g77' version of
`libf2c'.
* Improve `g77' driver and `libf2c' so that `g77 -v' yields version
information on the library.
* The `SNGL' and `FLOAT' intrinsics now are specific intrinsics,
instead of synonyms for the generic intrinsic `REAL'.
* New intrinsics have been added. These are `REALPART', `IMAGPART',
`COMPLEX', `LONG', and `SHORT'.
* A new group of intrinsics, `gnu', has been added to contain the
new `REALPART', `IMAGPART', and `COMPLEX' intrinsics. An old
group, `dcp', has been removed.
* Complain about industry-wide ambiguous references `REAL(EXPR)' and
`AIMAG(EXPR)', where EXPR is `DOUBLE COMPLEX' (or any complex type
other than `COMPLEX'), unless `-ff90' option specifies Fortran 90
interpretation or new `-fugly-complex' option, in conjunction with
`-fnot-f90', specifies `f2c' interpretation.
* Make improvements to diagnostics.
* Speed up compiler a bit.
* Improvements to documentation and indexing, including a new
chapter containing information on one, later more, diagnostics
that users are directed to pull up automatically via a message in
the diagnostic itself.
(Hence the menu item `M' for the node `Diagnostics' in the
top-level menu of the Info documentation.)
In previous versions:
=====================
Information on previous versions is archived in `gcc/gcc/f/news.texi'
following the test of the `DOC-OLDNEWS' macro.
automatically generated by info2www version 1.2.2.9