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Changes made to recent versions of GNU Fortran are listed below, with the most recent version first.
The changes are generally listed in order:
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.
For information on bugs in the GCC-2.95 version of g77,
see section Known Bugs In GNU Fortran.
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:
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)'.
Date intrinsic now returns the correct result
on big-endian systems.
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.
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.
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.
g77
as if they ended in `.for' and `.fpp', respectively.
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).
See section 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.
COMPLEX data type.
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.
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.
libf2c as of 1999-05-10.
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.
EGCS 1.1.2 versus EGCS 1.1.1: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.
See section IDate Intrinsic (VXT),
for more information.
Date_and_Time intrinsic (in libg2c)
to return the milliseconds value properly
in Values(8).
LStat intrinsic (in libg2c)
to return device-ID information properly
in SArray(7).
EGCS 1.1.1 versus EGCS 1.1: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.)
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.)
g77 so it no longer crashes compiling references
to the Rand intrinsic on some systems.
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).
EGCS 1.1 versus EGCS 1.0.3: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.
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.
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.
g77 for procedures containing ENTRY statements.
INTEGER expression.
g77 `-g' option so procedures that
use ENTRY can be stepped through, line by line,
in gdb.
REAL argument to intrinsics
Second and CPU_Time.
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.
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.
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.
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.
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).
OPEN, INQUIRE, READ, and
WRITE statements,
and about truncations of various sorts of constants.
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'.
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.
EGCS 1.1 versus g77 0.5.23: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.
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.
g77 crash
(or apparently infinite run-time)
when compiling certain complicated expressions
involving COMPLEX arithmetic
(especially multiplication).
SAVE attribute
or given initial values via DATA.
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.
Date_and_Time intrinsic now is
supported.
System_Clock intrinsic allows
the optional arguments (except for the Count
argument) to be omitted.
libf2c as of 1998-06-18.
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:
__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.)
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.)
g77 no longer
including patches for the gcc back end.
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.
gcc version 2.8,
and remove support for prior versions of gcc.
g77 now does all the driving,
just like gcc.
CASE DEFAULT no longer crashes g77.
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.
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.
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.
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.
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.
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).
OPEN, INQUIRE, READ, and
WRITE statements,
and about truncations of various sorts of constants.
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.
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.
DNRM2 routine.
The x87 coprocessor stack was being
mismanaged in cases involving assigned GOTO
and ASSIGN.
DTime intrinsic so as not to truncate
results to integer values (on some systems).
Signal intrinsic so it offers portable
support for 64-bit systems (such as Digital Alphas
running GNU/Linux).
NAMELIST on 64-bit
machines such as Alphas.
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).
g77 crash triggered by CASE statement with
an omitted lower or upper bound.
g77 crash compiling references to CPU_Time
intrinsic.
g77 crash
(or apparently infinite run-time)
when compiling certain complicated expressions
involving COMPLEX arithmetic
(especially multiplication).
g77 crash on statements such as
`PRINT *, (REAL(Z(I)),I=1,2)', where
`Z' is DOUBLE COMPLEX.
g++ crash.
INTEGER expression.
g77 `-g' option so procedures that
use ENTRY can be stepped through, line by line,
in gdb.
gcc back end for
Intel x86 architecture.
REAL argument to intrinsics
Second and CPU_Time.
Int2 and Int8.
tempnam, if available, to open scratch files
(as in `OPEN(STATUS='SCRATCH')')
so that the TMPDIR environment variable,
if present, is used.
gcc keyword restrict to
__restrict__, to avoid rejecting valid, existing,
C programs.
Support for restrict is now more like support
for complex.
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.)
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'.
libf2c.
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).
EGCS 1.0.2 versus EGCS 1.0.1:g77 crash triggered by CASE statement with
an omitted lower or upper bound.
g77 crash on statements such as
`PRINT *, (REAL(Z(I)),I=1,2)', where
`Z' is DOUBLE COMPLEX.
EGCS 1.0.1 versus EGCS 1.0:NAMELIST on 64-bit
machines such as Alphas.
EGCS 1.0 versus g77 0.5.21: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:
restrict keyword.
g77
being fully integrated with
the egcs variant of the gcc back end.
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.
DTime intrinsic so as not to truncate
results to integer values (on some systems).
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.
egcs versions of gcc.
g77 now does all the driving,
just like gcc.
Int2 and Int8.
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.)
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).
gcc (C, C++,
Fortran, and so on).
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).
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).
DATA
or similar to initialize a COMPLEX variable or
array to zero.
AND, OR,
or XOR intrinsics.
COMMON
or EQUIVALENCE variable
as the target of an ASSIGN
or assigned-GOTO statement.
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.
SAVE or the `-fno-automatic' option
is in effect.
This avoids a compiler crash in some cases.
DOUBLE PRECISION optimally on Pentium and
Pentium Pro architectures (586 and 686 in gcc).
g77.
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.
gcc back end so
certain complicated expressions involving COMPLEX
arithmetic (especially multiplication) don't appear to
take forever to compile.
gcc
back end.
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.)
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.
CHMOD intrinsic to work with file names
that have embedded blanks, commas, and so on.
SIGNAL intrinsic so it accepts an
optional third Status argument.
IDATE() intrinsic subroutine (VXT form)
so it accepts arguments in the correct order.
Documentation fixed accordingly, and for
GMTIME() and LTIME() as well.
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.
libU77 so it is more portable.
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.
restrict keyword in gcc
front end.
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.
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.
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.
INT2 and INT8 intrinsics.
CPU_TIME intrinsic.
ALARM intrinsic.
CTIME intrinsic now accepts any INTEGER
argument, not just INTEGER(KIND=2).
gcc `specs' file.
make rule g77-cross, used only for
cross-compiling.
libf2c build procedure to re-archive library
if previous attempt to archive was interrupted.
gcc to unroll loops only during the last
invocation (of as many as two invocations) of loop
optimization.
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.
libf2c as of 1997-08-16.
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.
ratfor command, available
separately.
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.
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'.
INTEGER(KIND=0) for future use.
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.)
See section Options Controlling Fortran Dialect,
for information on the `-ftypeless-boz' option.
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.
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.
See section Output Assumed To Flush, for more information.
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.
g77.
See section Other Dialects, for more information.
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.
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).
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.
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.
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.
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.
See section 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.
CONJG() and DCONJG() intrinsics now
are compiled in-line.
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.)
g77 uses a separate memory location
to hold assigned statement labels.)
See section Ugly Assigned Labels, for more information.
FORMAT and ENTRY statements now are allowed to
precede IMPLICIT NONE statements.
SELECT CASE on
CHARACTER type, instead of crashing, at compile time.
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).
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.
libf2c as of 1997-02-08, and
fix up some of the build procedures.
g77,
fixing minor bugs (such as deletion of any file
named `f771' in the parent directory of gcc/).
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.
g77 driver and libf2c so that `g77 -v'
yields version information on the library.
SNGL and FLOAT intrinsics now are
specific intrinsics, instead of synonyms for the
generic intrinsic REAL.
REALPART, IMAGPART,
COMPLEX,
LONG, and SHORT.
gnu, has been added
to contain the new REALPART, IMAGPART,
and COMPLEX intrinsics.
An old group, dcp, has been removed.
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.
M for the node
Diagnostics in the top-level menu of
the Info documentation.)
Information on previous versions is archived
in `egcs/gcc/f/news.texi'
following the test of the DOC-OLDNEWS macro.
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