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Re: Optimization advice for maintainers: go for low-hanging fruit
- From: Jan Hubicka <jh at suse dot cz>
- To: Martin Buchholz <martin at xemacs dot org>
- Cc: gcc at gcc dot gnu dot org
- Date: Fri, 20 Dec 2002 13:06:53 +0100
- Subject: Re: Optimization advice for maintainers: go for low-hanging fruit
- References: <15874.46305.491247.297301@wobble.local>
> I've been staring at a lot of g++-generated x86 assembler, trying to
> coax g++ into creating better code, and creating a bunch of
> optimization-related PRs. Overall, I'm disappointed by gcc's ability
> to optimize some very simple things like constant-folding.
>
> The most distressing thing about the failures is that gcc is
> invariably capable of performing all the optimizations I care about,
> just not consistently. Seemingly irrelevant random features of the
> source code seem to inhibit optimizations from being performed.
Can you send some testcases where GCC fails to do the transformation?
Honza