Re: powerpc-ibm-aix4.3.3.0 bootstrap issue

[David Edelsohn <dje at watson dot ibm dot com>]

	I have been unable to cleanly bootstrap GCC on the trunk since the
HOST_WIDE_INT use of "long long" change.  The compiler works, but I get
random comparison errors of various files when bootstrapping.  I observed
that the resulting code always is correct and works, but stage2 and stage3
sometimes produces code reloading a TOC entry and sometimes copy the value
already in a register.

	I tried bootstrapping from scratch with AIX Visual Age C Compiler,
gcc-2.95.3, and gcc-3.0.1.  All encountered the similar problems -- not in
the exact same files, but all showed comparison failures.  I doubt that
all versions miscompile reload.c.

	I thought that it might be caused by an error in a hashtable
lookup or a hash value that depends on an address.  It could be something
non-deterministic in reload as well.  I and others spent a lot of time
over the summer building GCC with memory checking libraries and could not
find any wild writes that would corrupt something.

	This problem does not occur for 32-bit PowerPC which uses "long"
for HOST_WIDE_INT.  Maybe it is an error in one of the 32-bit DImode
patterns implementing "long long".

	I would appreciate any help in trying to track this down as I am
not having much luck.

Thanks, David