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Re: 2.95/3.x regression in the compilation of computed gotos?
- From: Robert Dewar <dewar at gnat dot com>
- To: duchier at ps dot uni-sb dot de
- Cc: gcc at gcc dot gnu dot org
- Date: Thu, 22 Jan 2004 10:32:51 -0500
- Subject: Re: 2.95/3.x regression in the compilation of computed gotos?
- References: <87fze8i2oq.fsf@tdg.loria.fr>
duchier@ps.uni-sb.de wrote:
2.95:
addl $4,%eax
jmp *(%eax)
3.3.2:
addl $4,%ecx
movl (%ecx),%edx
jmp *%edx
Isn't this a regression?
In such a case, it is helpful to know why you think this is a
regression. It is not clear at all to me that the 2.95 code
is better. Either attach an analysis or a timing test result.
On these kinds of machines, you can't rely on obvious common
sense to figure out what sequence of code is better!