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Re: Add macros for diagnostic control, use them in locale/weightwc.h
- From: Joseph Myers <joseph at codesourcery dot com>
- To: Paul Eggert <eggert at cs dot ucla dot edu>
- Cc: Roland McGrath <roland at hack dot frob dot com>, <libc-alpha at sourceware dot org>
- Date: Wed, 19 Nov 2014 00:06:40 +0000
- Subject: Re: Add macros for diagnostic control, use them in locale/weightwc.h
- Authentication-results: sourceware.org; auth=none
- References: <alpine dot DEB dot 2 dot 10 dot 1411181803130 dot 11642 at digraph dot polyomino dot org dot uk> <546BB1B1 dot 50000 at cs dot ucla dot edu> <20141118211808 dot 2053D2C3B22 at topped-with-meat dot com> <546BC831 dot 2010006 at cs dot ucla dot edu> <alpine dot DEB dot 2 dot 10 dot 1411182301110 dot 18922 at digraph dot polyomino dot org dot uk> <546BDD19 dot 6000908 at cs dot ucla dot edu>
On Tue, 18 Nov 2014, Paul Eggert wrote:
> > Disabling for the relevant block of source lines, on all architectures and
> > for all GCC versions that support the relevant -W option, is a pragmatic
> > choice
>
> Yes, and I guess my point is that the pragmatic choice we've taken in Gnulib
> is to disable diagnostics at the top level, as GCC has too many bugs in this
> area for us to go on wild goose chases trying to fine-tune diagnostics in
> smaller areas. I'm skeptical whether it'll be worthwhile for glibc to chase
> those geese either, at least in the near future.
This is the one such optimization-related warning I see on x86_64
(building glibc, rather than the testsuite - but in the testsuite we can
be quite free with using dumb code, redundant initialization etc. to avoid
warnings, without being at all concerned about resulting inefficiencies)
with 4.9. I think there are only a handful I've seen on other
architectures. (There may of course be some currently disabled with -Wno-
options for whole files in the makefiles.)
--
Joseph S. Myers
joseph@codesourcery.com