@c in the standalone derivations of this file (e.g. BUGS).
@set copyrights-bugs 1995-1999
-@set last-update-bugs 1999-03-15
+@set last-update-bugs 1999-04-03
@include root.texi
Version 0.6 should solve most or all remaining problems
(such as cross-compiling involving 64-bit machines).
-@cindex COMPLEX support
-@cindex support, COMPLEX
-@item
-Maintainers of @code{gcc} report that the back end definitely has ``broken''
-support for @code{COMPLEX} types.
-Based on their input, it seems many of
-the problems affect only the more-general facilities for gcc's
-@code{__complex__} type, such as @code{__complex__ int}
-(where the real and imaginary parts are integers) that GNU
-Fortran does not use.
-
-Version 0.5.20 of @code{g77} works around this
-problem by not using the back end's support for @code{COMPLEX}.
-The new option @samp{-fno-emulate-complex} avoids the work-around,
-reverting to using the same ``broken'' mechanism as that used
-by versions of @code{g77} prior to 0.5.20.
-
@cindex padding
@cindex structures
@cindex common blocks
@c %**start of header
@setfilename g77.info
-@set last-update 1999-04-02
+@set last-update 1999-04-03
@set copyrights-g77 1995-1999
@include root.texi
-fpcc-struct-return -freg-struct-return
-fshort-double -fno-common -fpack-struct
-fzeros -fno-second-underscore
--fdebug-kludge -fno-emulate-complex
+-fdebug-kludge -femulate-complex
-falias-check -fargument-alias
-fargument-noalias -fno-argument-noalias-global
-fno-globals
and @code{gdb} exist that provide proper access to debugging information on
@code{COMMON} and @code{EQUIVALENCE} members.
-@cindex -fno-emulate-complex option
-@cindex options, -fno-emulate-complex
-@item -fno-emulate-complex
-Implement @code{COMPLEX} arithmetic using the facilities in
+@cindex -femulate-complex option
+@cindex options, -femulate-complex
+@item -femulate-complex
+Implement @code{COMPLEX} arithmetic via emulation,
+instead of using the facilities of
the @code{gcc} back end that provide direct support of
-@code{complex} arithmetic, instead of emulating the arithmetic.
+@code{complex} arithmetic.
-@code{gcc} has some known problems in its back-end support
+(@code{gcc} had some bugs in its back-end support
for @code{complex} arithmetic, due primarily to the support not being
-completed as of version 2.7.2.2.
-Other front ends for the @code{gcc} back end avoid this problem
-by emulating @code{complex} arithmetic at a higher level, so the
-back end sees arithmetic on the real and imaginary components.
-To make @code{g77} more portable to systems where @code{complex}
-support in the @code{gcc} back end is particularly troublesome,
-@code{g77} now defaults to performing the same kinds of emulations
-done by these other front ends.
-
-Use @samp{-fno-emulate-complex} to try the @code{complex} support
-in the @code{gcc} back end, in case it works and produces faster
-programs.
-So far, all the known bugs seem to involve compile-time crashes,
-rather than the generation of incorrect code.
+completed as of version 2.8.1 and @code{egcs} 1.1.2.)
+
+Use @samp{-femulate-complex} if you suspect code-generation bugs,
+or experience compiler crashes,
+that might result from @code{g77} using the @code{COMPLEX} support
+in the @code{gcc} back end.
+If using that option fixes the bugs or crashes you are seeing,
+that indicates a likely @code{g77} bugs
+(though, all compiler crashes are considered bugs),
+so, please report it.
+(Note that the known bugs, now believed fixed, produced compiler crashes
+rather than causing the generation of incorrect code.)
Use of this option should not affect how Fortran code compiled
by @code{g77} works in terms of its interfaces to other code,
e.g. that compiled by @code{f2c}.
-@emph{Caution:} Future versions of @code{g77} are likely to change
-the default for this option to
-@samp{-fno-emulate-complex}, and perhaps someday ignore both forms
+@emph{Caution:} Future versions of @code{g77} might ignore both forms
of this option.
-Also, it is possible that use of the @samp{-fno-emulate-complex} option
-could result in incorrect code being silently produced by @code{g77}.
-But, this is generally true of compilers anyway, so, as usual, test
-the programs you compile before assuming they are working.
-
@cindex -falias-check option
@cindex options, -falias-check
@cindex -fargument-alias option
(In @code{gdb}, this is accomplished via @samp{set lang c} and
either @samp{set lang fortran} or @samp{set lang auto}.)
-@emph{Note:} Compiling with the @samp{-fno-emulate-complex} option
-avoids the debugging problem, but is known to cause other problems
-like compiler crashes and generation of incorrect code, so it is
-not recommended.
-
@node Arrays
@section Arrays (DIMENSION)
@cindex DIMENSION statement
git://gcc.gnu.org / gcc.git / commitdiff