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sysdeps/ieee754/soft-fp: ignore maybe-uninitialized with -O [BZ #19444] 

* with -O, -O1, -Os it fails with:

In file included from ../soft-fp/soft-fp.h:318,
                 from ../sysdeps/ieee754/soft-fp/s_fdiv.c:28:
../sysdeps/ieee754/soft-fp/s_fdiv.c: In function '__fdiv':
../soft-fp/op-2.h:98:25: error: 'R_f1' may be used uninitialized in this function [-Werror=maybe-uninitialized]
        X##_f0 = (X##_f1 << (_FP_W_TYPE_SIZE - (N)) | X##_f0 >> (N) \
                         ^~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f1' was declared here
   FP_DECL_D (R);
              ^
../soft-fp/op-2.h:37:36: note: in definition of macro '_FP_FRAC_DECL_2'
   _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
                                    ^
../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
 # define FP_DECL_D(X)  _FP_DECL (2, X)
                        ^~~~~~~~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
   FP_DECL_D (R);
   ^~~~~~~~~
../soft-fp/op-2.h:101:17: error: 'R_f0' may be used uninitialized in this function [-Werror=maybe-uninitialized]
       : (X##_f0 << (_FP_W_TYPE_SIZE - (N))) != 0)); \
                 ^~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f0' was declared here
   FP_DECL_D (R);
              ^
../soft-fp/op-2.h:37:14: note: in definition of macro '_FP_FRAC_DECL_2'
   _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
              ^
../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
 # define FP_DECL_D(X)  _FP_DECL (2, X)
                        ^~~~~~~~
../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
   FP_DECL_D (R);
   ^~~~~~~~~

Build tested with Yocto for ARM, AARCH64, X86, X86_64, PPC, MIPS, MIPS64
with -O, -O1, -Os.
For AARCH64 it needs one more fix in locale for -Os.

	[BZ #19444]
	* sysdeps/ieee754/soft-fp/s_fdiv.c: Include <libc-diag.h> and use
	DIAG_PUSH_NEEDS_COMMENT, DIAG_IGNORE_NEEDS_COMMENT and
	DIAG_POP_NEEDS_COMMENT to disable -Wmaybe-uninitialized.

(cherry picked from commit 4a06ceea33)
This commit is contained in:
Martin Jansa 2018-10-02 15:38:43 +00:00 committed by Adhemerval Zanella
parent 2a8612b278
commit 1e5c5303a5
3 changed files with 20 additions and 0 deletions
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7
ChangeLog
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@ -1,3 +1,10 @@
2019-01-03 Martin Jansa <Martin.Jansa@gmail.com>
[BZ #19444]
* sysdeps/ieee754/soft-fp/s_fdiv.c: Include <libc-diag.h> and use
DIAG_PUSH_NEEDS_COMMENT, DIAG_IGNORE_NEEDS_COMMENT and
DIAG_POP_NEEDS_COMMENT to disable -Wmaybe-uninitialized.
2019-01-02 Aurelien Jarno <aurelien@aurel32.net>
[BZ #24034]

1
NEWS
View File

@ -9,6 +9,7 @@ Version 2.28.1
The following bugs are resolved with this release:
[19444] build failures with -O1 due to -Wmaybe-uninitialized
[20209] localedata: Spelling mistake for Sunday in Greenlandic kl_GL
[22927] libanl: properly cleanup if first helper thread creation failed
[23400] stdlib/test-bz22786.c creates temporary files in glibc source tree

12
sysdeps/ieee754/soft-fp/s_fdiv.c
View File

@ -25,6 +25,16 @@
#undef fdivl
#include <math-narrow.h>
#include <libc-diag.h>
/* R_f[01] are not set in cases where they are not used in packing,
but the compiler does not see that they are set in all cases where
they are used, resulting in warnings that they may be used
uninitialized. The location of the warning differs in different
versions of GCC, it may be where R is defined using a macro or it
may be where the macro is defined. This happens only with -O1. */
DIAG_PUSH_NEEDS_COMMENT;
DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
#include <soft-fp.h>
#include <single.h>
#include <double.h>
@ -53,4 +63,6 @@ __fdiv (double x, double y)
CHECK_NARROW_DIV (ret, x, y);
return ret;
}
DIAG_POP_NEEDS_COMMENT;
libm_alias_float_double (div)