This is the mail archive of the
gcc-patches@gcc.gnu.org
mailing list for the GCC project.
Re: [tree-ssa] Problem with constant folding
- From: law at redhat dot com
- To: Zdenek Dvorak <rakdver at atrey dot karlin dot mff dot cuni dot cz>
- Cc: gcc-patches at gcc dot gnu dot org, dnovillo at redhat dot com
- Date: Thu, 11 Dec 2003 20:21:29 -0700
- Subject: Re: [tree-ssa] Problem with constant folding
- Reply-to: law at redhat dot com
In message <20031209083351.GA14478@atrey.karlin.mff.cuni.cz>, Zdenek Dvorak wri
tes:
>Hello,
>
>[snip] (http://gcc.gnu.org/ml/gcc-patches/2003-12/msg00786.html)
>
>> The patch below fixes the problem by preventing the overflowed constants
>> from being propagated. It is probably way too conservative, but I was
>> not able to determine the place where to fix the problem in other way.
>
>... and unfortunately it is also wrong, since it fails to bootstrap. Does
>someone has an idea what is the right way to fix this?
Your approach seems pretty reasonable. And it seems extremely odd that
it wouldn't bootstrap since it ought to just force such constants into
new variables and prevent them from being propagated by the optimizers.
I'd suggest investigating why the patch didn't bootstrap.
jeff