This is the mail archive of the
gcc-help@gcc.gnu.org
mailing list for the GCC project.
Re: gcc 4.1 -O1 problem
- From: John Love-Jensen <eljay at adobe dot com>
- To: Kevin Shanahan <kmshanah at disenchant dot net>
- Cc: MSX to GCC <gcc-help at gcc dot gnu dot org>
- Date: Thu, 16 Mar 2006 06:50:42 -0600
- Subject: Re: gcc 4.1 -O1 problem
Hi Kevin,
I think your code is correct, and the GCC 4.1 compiler has a boo-boo. File
a bug report, please, including the code snippet that reproduces the
suspected bug, what platform, and the command line used to compile the code.
See "Bugs" section on the left column of <http://gcc.gnu.org/>.
Anyway, here's a couple bits of tid (as I understand it):
-O0 disables all optimizations. The -fenable-something likely don't enable
the specified optimization when -O0 is specified (if there are exceptions,
I'm not aware of them).
-fverbose-asm (with -S or -save-temps) is useful to ascertain what
optimizations are happenings with -O1, -O2, -O3, -Os.
As I understand it, only select optimizations are twiddlible with -f flags,
but not all of the possible optimizations.
HTH,
--Eljay
PS: twiddlible ... *heh*