RE: Searching for the gcc-2.95 problem

[Julian Seward (Intl Vendor)]

> I want to try to localize the problems occurring when using a  gcc-2.95
compiled
> ghc-4.04. As I stated in a recent mail, the bug seems to be somewhere in
the
> runtime system/libraries.  [...]

<Speculation>

gcc-2.95 has more aggressive alias analysis than previous egcs or gcc
versions.  As a result, some programs don't compile correctly with 2.95
because they break ANSI C's aliasing rules in subtle ways, which didn't
matter with previous gcc/egcs-s, but does now.  

A couple of examples which come to mind are: the Linux 2.2 and 2.3 series
kernels, and the Wine windows-on-Linux-library.

Perhaps the same is happening with GHC's RTS.  You can ask gcc-2.95 to 
be less aggressive by using -fno-strict-aliasing (I think; consult
the documentation).  I'd be interested to hear if this makes any
difference.

</Speculation>

J