PowerPC build breakage caused by 8/25/98 loop.c change

David Edelsohn dje@watson.ibm.com
Fri Sep 18 22:10:00 GMT 1998

>>>>> Mark Mitchell writes:

Mark> I doubt the AVOID_CCMODE_COPIES bit is to blame; if anything went
Mark> wrong with that code it would probably a trigger an immediate crash as
Mark> load_mems_and_recount_loop_regs_set runs.  It sounds like you're
Mark> seeing a failure further down the line, right?  

	There are a rapid succession of loop.c changes betwen 8/25 and
8/28.  With all of the compiler changes around that time, the compiler
generates an internal error.  Within a day, the compiler produces
executables which crash.  Then finally by 8/28, the compiler simply
produces code which behaves incorrectly.  It is hard for me to disentangle
which loop.c changes are new which could be causing the current failure
from those which are incremental fixes to the previous patches.

	I don't have a lot of time to analyze this.  Performing various
checkouts and attempting to bootstrap was a very simple, repetitive
operation to narrow down the source of the failure.  Maybe the
check_dbra_loop changes that were interleaved are causing the current

	I'm trying to bootstrap again with loop.c r1.66 prior to the
check_dbra_loop changes, prior to Jeff's scan_loop tweak.


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