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Re: [RFC] [autovect patch] Implement vectorization hints
- From: Zack Weinberg <zack at codesourcery dot com>
- To: Steven Bosscher <stevenb at suse dot de>
- Cc: gcc-patches at gcc dot gnu dot org, Devang Patel <dpatel at apple dot com>, joseph at codesourcery dot com
- Date: Sun, 27 Feb 2005 11:22:12 -0800
- Subject: Re: [RFC] [autovect patch] Implement vectorization hints
- References: <B397FD6A-85F5-42B2-8F66-E2BF57641F31@apple.com><firstname.lastname@example.org>
Steven Bosscher <email@example.com> writes:
> I was hoping for something more general, to be honest. For the
> other #pragma-needing projects there has to be interaction with the
> parser, and it looks like you need that, too. We have the new C
> parser now, so it is actually possible, and the right time now, to
> think about a general way to have this kind of pragmas. IIRC Zack
> had some ideas about how to do this...?
Well, the basic idea is that some pragmas should generate IL
statements, which would then be properly tied to the associated
language construct. I'm not sure what the right tree representation
is. For things like #pragma STDC FP_CONTRACT OFF it's a little
simpler, because the semantics are "has effect from point of
appearance to end of immediately enclosing block", so the optimizers
can just look for a PRAGMA_EXPR inside each lexical block. I'm not
sure how to tie a pragma to the next language-level loop.