From: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
To: Joseph Myers <joseph@codesourcery.com>
Cc: libc-alpha@sourceware.org, gabriel@inconstante.eti.br,
raji@linux.ibm.com
Subject: Re: [PATCH 7/9] Refactor math-finite.h and introduce mathcalls-redir.h
Date: Wed, 13 Jun 2018 21:36:00 -0000 [thread overview]
Message-ID: <878t7icqtd.fsf@linux.ibm.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1806062312290.24720@digraph.polyomino.org.uk>
Joseph Myers <joseph@codesourcery.com> writes:
> On Wed, 6 Jun 2018, Tulio Magno Quites Machado Filho wrote:
>
>> On a new enough compiler, redirecting the same function twice can cause
>> -Werror=pragmas errors. This issue may appear when redirecting an ISO C
>> floating point function to a different ABI at the same time that finite
>> redirections are expected.
>
> Does this issue already appear with -mlong-double-64? If so, it should
> definitely be separated out from this patch series and have a bug filed in
> Bugzilla as usual for anything fixing a bug that was user-visible in a
> release.
Yes, I can reproduce it in our tests if I replace -mlong-double-128 with
-mlong-double-64.
However, this is not user-visible because this warning is ignored in system
headers.
Do you still think a bug report is necessary?
> The approach taken in this patch involves a lot of duplication of both
> function prototypes and the feature-test-macro conditions on when those
> functions are declared (duplicating them for functions not included in
> math-finite.h, when previously only those in math-finite.h had such
> duplication). Such duplication is, from experience, fragile and a bad
> idea; the conditions and declarations are too likely to get out of sync.
Agreed.
> Instead, I'd suggest merging bits/math-finite.h into bits/mathcalls.h as
> much as possible - have macros such as __MATHCALL_FINITE that are called
> in bits/mathcalls.h to declare the functions with __*_finite variants, and
> with __MATHCALL_FINITE defined the same as __MATHCALL when the finite
> function variants aren't in use. That way you have just a single
> redirection for each function. (You'll need a sysdeps bits/ header for an
> architecture, i.e. ia64, to declare it doesn't support the _finite
> functions at all.)
It doesn't work well this way because we have prototypes with extra attributes,
e.g:
__MATHDECL_1 (int, totalorder,, (_Mdouble_ __x, _Mdouble_ __y))
__attribute__ ((__const__));
So, if I do not define __MATHDECL_1 in bits/math-finite.h, this code would end
up as an invalid code:
__attribute__ ((__const__));
I managed to remove bits/math-redir.h and modified both math.h and
bits/math-finite.h to reuse bits/mathcalls.h. I had to keep using
__MATH_DECLARE_FINITE and __MATH_DECLARE_NON_FINITE.
Would this be acceptable?
--
Tulio Magno
next prev parent reply other threads:[~2018-06-13 21:36 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-06 22:41 [PATCH 0/9] Introduce ieee128 symbols and redirections Tulio Magno Quites Machado Filho
2018-06-06 22:41 ` [PATCH 2/9] Move declare_mgen_finite_alias definition Tulio Magno Quites Machado Filho
2018-06-07 13:25 ` Joseph Myers
2018-06-06 22:41 ` [PATCH 3/9] ldbl-128ibm-compat: Provide a generic scalb implementation Tulio Magno Quites Machado Filho
2018-06-06 22:41 ` [PATCH 4/9] ldbl-128ibm-compat: Add a generic significand() implementation Tulio Magno Quites Machado Filho
2018-06-07 13:38 ` Joseph Myers
2018-06-15 20:16 ` Tulio Magno Quites Machado Filho
2018-06-15 20:20 ` Tulio Magno Quites Machado Filho
2018-06-06 22:41 ` [PATCH 1/9] ldbl-128ibm-compat: Create libm-alias-float128.h Tulio Magno Quites Machado Filho
2018-06-06 23:05 ` Joseph Myers
2018-06-13 20:16 ` Tulio Magno Quites Machado Filho
2018-06-06 22:42 ` [PATCH 8/9] ldbl-128ibm-compat: Redirect long double functions to f128/ieee128 functions Tulio Magno Quites Machado Filho
2018-06-06 22:42 ` [PATCH 5/9] ldbl-128ibm-compat: Provide ISO C functions not provided by the _Float128 API Tulio Magno Quites Machado Filho
2018-06-07 14:51 ` Joseph Myers
2018-06-13 21:41 ` Tulio Magno Quites Machado Filho
2018-06-06 22:42 ` [PATCH 7/9] Refactor math-finite.h and introduce mathcalls-redir.h Tulio Magno Quites Machado Filho
2018-06-06 23:23 ` Joseph Myers
2018-06-13 21:36 ` Tulio Magno Quites Machado Filho [this message]
2018-06-13 22:58 ` Joseph Myers
2018-06-14 18:07 ` Tulio Magno Quites Machado Filho
2018-06-06 22:42 ` [PATCH 6/9] ldbl-128ibm-compat: Provide nexttoward functions Tulio Magno Quites Machado Filho
2018-06-06 22:43 ` [PATCH 9/9] ldbl-128ibm-compat: Redirect complex math functions Tulio Magno Quites Machado Filho
2018-06-06 23:11 ` [PATCH 0/9] Introduce ieee128 symbols and redirections Joseph Myers
2018-06-13 20:25 ` Tulio Magno Quites Machado Filho
2018-06-13 20:28 ` Joseph Myers
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