This is the mail archive of the
gcc@gcc.gnu.org
mailing list for the GCC project.
Re: Should -fcross-jumping be part of -O1?
- From: Joe Buck <jbuck at synopsys dot com>
- To: Robert Dewar <dewar at gnat dot com>
- Cc: David Carlton <carlton at kealia dot com>, Zack Weinberg <zack at codesourcery dot com>, gcc mailing list <gcc at gcc dot gnu dot org>
- Date: Tue, 2 Dec 2003 12:55:53 -0800
- Subject: Re: Should -fcross-jumping be part of -O1?
- References: <3FC0DCD0.9000106@coyotegulch.com> <20031123162248.GA336@atrey.karlin.mff.cuni.cz> <3FC0EC7E.7070800@coyotegulch.com> <20031123173321.GO15575@kam.mff.cuni.cz> <3FC0F7A6.4010103@coyotegulch.com> <20031123181903.GW15575@kam.mff.cuni.cz> <3FC11F13.2090708@coyotegulch.com> <877k1fmxr4.fsf@egil.codesourcery.com> <yf2znebtaxt.fsf@hawaii.kealia.com> <3FCCDFC9.5070209@gnat.com>
On Tue, Dec 02, 2003 at 01:54:01PM -0500, Robert Dewar wrote:
> One real problem with gcc is that -O0 is too painfully stupid. It
> generates piles of junk code.
The main purpose of -O0 is for debugging. The user of -O0 wants a
fast compile and wants to be able to effectively debug. Accordingly,
it seems to me that intra-statement optimization is fine, as long as,
at any point where the user could set a breakpoint, the state matches
the code (generally meaning that in-memory objects have the correct
state). However, what the user would not want is for -O0 to get slower.