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g77 bug report


Dear g77 maintainers,

I know how useless vague bug reports are, but I have a significant problem with
g77 in the egcs packaage that comes with RedHat 6, and I am hoping that the
symptoms could suggest where I could start in fixing it.

In short : I have a large C/Fortran package which I build with gcc and g77, and
if I have optimising turned on (--O3 or even -O1) as I have always done in the
past, "nothing works" - I get core-dumps, NaNs appearing out of nowhere & so on
- general chaos.  It seems to work fine with optimising turned off, but I have
always been able to use -O3 with g77 0.5.18 and 0.5.21 which I have built with
previously.  The same package works fine with all optimising using Sun,IBM and
Dec compilers, so it definitely looks like a g77 -O problem to me.

I have used the EGCS 1.1.2 supplied with RedHat6, and tried replacing that with
the current (2.9.5?) EGCS version, but the problem remains the same.

Performance is critical in the application (so I need -O), and I need to use the
latest (?) Linux kernel because of the dual-CPU (586) support.  

Because of the size & nature of the package it will be difficult to supply a
simple job that fails, so for now I have two questions :

    1. Is there is a known problem with optimisation, post 0.5.21 ?  

    2. Can I revert to using the g77-0.5.21 / gcc-2.7.2.3.f.1 with RedHat 6
       or is there some change that prevents this (I suspect that glibc
       might have changed formats or something...)

Again, SORRY to be so un-detailed, but any advice would be greatly appreciated!

Many thanks,
Jonathan Ravens
J.Ravens@gns.cri.nz
       


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