glibc/soft-fp/fmadf4.c
Joseph Myers dc6b5aed1b Fix soft-fp fma for -Wuninitialized.
The soft-fp implementations of fma produce -Wuninitialized warnings
because, in the cases where the result is not a nonzero finite value,
the soft-fp does not set the exponent of the result since the (cooked)
packing will do so, but the compiler does not then see that the
exponent is always set in packing before it's used if it wasn't set
earlier.  This patch uses DIAG_* macros to suppress those warnings.

Tested for mips64.  (In fact this allows the mips64 build to complete
with the -Wno-uninitialized removed from math/Makefile, but more
cleanups are still needed in the ldbl-128ibm code for uninitialized
warnings there.)

	* soft-fp/fmadf4.c: Include <libc-internal.h>.
	(__fma): Ignore uninitialized warnings around packing.
	* soft-fp/fmasf4.c: Include <libc-internal.h>.
	(__fmaf): Ignore uninitialized warnings around packing.
	* soft-fp/fmatf4.c: Include <libc-internal.h>.
	(__fmal): Ignore uninitialized warnings around packing.
2015-05-22 20:28:50 +00:00

72 lines
2.2 KiB
C

/* Implement fma using soft-fp.
Copyright (C) 2013-2015 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
In addition to the permissions in the GNU Lesser General Public
License, the Free Software Foundation gives you unlimited
permission to link the compiled version of this file into
combinations with other programs, and to distribute those
combinations without any restriction coming from the use of this
file. (The Lesser General Public License restrictions do apply in
other respects; for example, they cover modification of the file,
and distribution when not linked into a combine executable.)
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
#include <libc-internal.h>
#include <math.h>
#include "soft-fp.h"
#include "double.h"
double
__fma (double a, double b, double c)
{
FP_DECL_EX;
FP_DECL_D (A);
FP_DECL_D (B);
FP_DECL_D (C);
FP_DECL_D (R);
double r;
FP_INIT_ROUNDMODE;
FP_UNPACK_D (A, a);
FP_UNPACK_D (B, b);
FP_UNPACK_D (C, c);
FP_FMA_D (R, A, B, C);
/* R_e is not set in cases where it is not used in packing, but the
compiler does not see that it is set in all cases where it is
used, resulting in warnings that it may be used
uninitialized. */
DIAG_PUSH_NEEDS_COMMENT;
#if __GNUC_PREREQ (4, 7)
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wmaybe-uninitialized");
#else
DIAG_IGNORE_NEEDS_COMMENT (4.9, "-Wuninitialized");
#endif
FP_PACK_D (r, R);
DIAG_POP_NEEDS_COMMENT;
FP_HANDLE_EXCEPTIONS;
return r;
}
#ifndef __fma
weak_alias (__fma, fma)
#endif
#ifdef NO_LONG_DOUBLE
strong_alias (__fma, __fmal)
weak_alias (__fmal, fmal)
#endif