fortran/893: Preliminary loop exit compiled wrongly

[Toon Moene]

List subscription wrote:
^^^^^^^^^^^^^^^^^ Hmmmm, you probably want to change this ;-)

> I want to stress that the bug reported below is very serious and it is
> present in all snapshots of gcc after gcc-2.95.2

That's amazing - I believe it's less than two months ago that Martin
Kahlert reported this bug.  It's also hard to trigger; removing the
`WRITE' statement just before the abort call makes it go away.

> gcc-2.95.2 is still compiling correctly that example.
> 
> When I mean serious, I mean that for our codes (MonteCarlo's for high
> energy physics) there are bugs popping up everywhere. I found at least
> 7 different miscompiled routines in a few minutes. Inspections of the
> first two showed problems similar to the example below. I am not
> sure all problems are related to this bug only, however I see no point
> in going on before getting a patch.

Yep, I wouldn't jump to the conclusion that they're all one and the same
bug.  We would be very grateful if you were able to isolate some more
examples of bugs - this is the time to get them in the testsuite, so
that we can be certain they're fixed before GCC 3.0 hits the archives.

> Of course all problems disappear compiling with the (old) egcs-1.1.2

Amazing, given all the bugs we *know* are in egcs-1.1.2 ;-)

> and at least for those two routines I investigated, using gcc-2.95.2.

> I have a question (in order to try to survive meanwhile);
> is there any known incompatibility/patch I have to take care of in order
> to rebuild correctly gcc-2.95.2 on a system running glibc-2.2 (RH7)?

There's a simple patch to apply to GCC 2.95.2 to make it compilable on
RH7 and any glibc-2.2 system.  Unfortunately, at present I can't seem to
find it (help !).

> And in case this can be done, which are the binary incompatibilities
> (we link together c and fortran modules and sometimes c++ ones)?

You can't mix C++ objects from 2.95.x and RH7's compiler; neither can
you mix C++ objects from RH7's compiler and current snapshots. 
Otherwise we do not know of any incompatibilities.

Hope this helps,

-- 
Toon Moene - mailto:toon@moene.indiv.nluug.nl - phoneto: +31 346 214290
Saturnushof 14, 3738 XG  Maartensdijk, The Netherlands
GNU Fortran 77: http://gcc.gnu.org/onlinedocs/g77_news.html
GNU Fortran 95: http://g95.sourceforge.net/ (under construction)