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Re: [PATCH] Fix optimization regression in constant folder
- From: Eric Botcazou <ebotcazou at adacore dot com>
- To: "Richard Guenther" <richard dot guenther at gmail dot com>
- Cc: "Richard Kenner" <kenner at vlsi1 dot ultra dot nyu dot edu>, gcc-patches at gcc dot gnu dot org, iant at google dot com, matz at suse dot de
- Date: Mon, 1 Oct 2007 15:08:41 +0200
- Subject: Re: [PATCH] Fix optimization regression in constant folder
- References: <email@example.com> <10710011233.AA10135@vlsi1.ultra.nyu.edu> <firstname.lastname@example.org>
> You say you need special semantics because otherwise optimization won't
> work. This needs testcases. Otherwise just mapping sizetype semantics to
> an _existing_ semantic makes most sense as it reduces diversity of
> semantics and causes less confusion.
You're rewriting history, sizetype semantics already exists, just look at the
definition of TYPE_IS_SIZETYPE in tree.h and its uses in fold-const.c.
> Look at all the places we _don't_specialize sizetypes! You want to audit
> all these?
No, we just want to avoid consciously harming the compiler. In my experience,
a single line in fold-const.c can sometimes be more effective than an entire