git.libre-soc.org Git - buildroot.git/blob

   1 From 4a06ceea33ecc220bbfe264d8f1e74de2f04e90d Mon Sep 17 00:00:00 2001
   2 From: Martin Jansa <Martin.Jansa@gmail.com>
   3 Date: Tue, 2 Oct 2018 15:38:43 +0000
   4 Subject: [PATCH] sysdeps/ieee754/soft-fp: ignore maybe-uninitialized with -O
   5  [BZ #19444]
   6
   7 * with -O, -O1, -Os it fails with:
   8
   9 In file included from ../soft-fp/soft-fp.h:318,
  10                  from ../sysdeps/ieee754/soft-fp/s_fdiv.c:28:
  11 ../sysdeps/ieee754/soft-fp/s_fdiv.c: In function '__fdiv':
  12 ../soft-fp/op-2.h:98:25: error: 'R_f1' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  13         X##_f0 = (X##_f1 << (_FP_W_TYPE_SIZE - (N)) | X##_f0 >> (N) \
  14                          ^~
  15 ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f1' was declared here
  16    FP_DECL_D (R);
  17               ^
  18 ../soft-fp/op-2.h:37:36: note: in definition of macro '_FP_FRAC_DECL_2'
  19    _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
  20                                     ^
  21 ../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
  22  # define FP_DECL_D(X)  _FP_DECL (2, X)
  23                         ^~~~~~~~
  24 ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
  25    FP_DECL_D (R);
  26    ^~~~~~~~~
  27 ../soft-fp/op-2.h:101:17: error: 'R_f0' may be used uninitialized in this function [-Werror=maybe-uninitialized]
  28        : (X##_f0 << (_FP_W_TYPE_SIZE - (N))) != 0)); \
  29                  ^~
  30 ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:14: note: 'R_f0' was declared here
  31    FP_DECL_D (R);
  32               ^
  33 ../soft-fp/op-2.h:37:14: note: in definition of macro '_FP_FRAC_DECL_2'
  34    _FP_W_TYPE X##_f0 _FP_ZERO_INIT, X##_f1 _FP_ZERO_INIT
  35               ^
  36 ../soft-fp/double.h:95:24: note: in expansion of macro '_FP_DECL'
  37  # define FP_DECL_D(X)  _FP_DECL (2, X)
  38                         ^~~~~~~~
  39 ../sysdeps/ieee754/soft-fp/s_fdiv.c:38:3: note: in expansion of macro 'FP_DECL_D'
  40    FP_DECL_D (R);
  41    ^~~~~~~~~
  42
  43 Build tested with Yocto for ARM, AARCH64, X86, X86_64, PPC, MIPS, MIPS64
  44 with -O, -O1, -Os.
  45 For AARCH64 it needs one more fix in locale for -Os.
  46
  47         [BZ #19444]
  48         * sysdeps/ieee754/soft-fp/s_fdiv.c: Include <libc-diag.h> and use
  49         DIAG_PUSH_NEEDS_COMMENT, DIAG_IGNORE_NEEDS_COMMENT and
  50         DIAG_POP_NEEDS_COMMENT to disable -Wmaybe-uninitialized.
  51
  52
  53 Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
  54 ---
  55  sysdeps/ieee754/soft-fp/s_fdiv.c | 12 ++++++++++++
  56  1 files changed, 12 insertions(+)
  57
  58 diff --git a/sysdeps/ieee754/soft-fp/s_fdiv.c b/sysdeps/ieee754/soft-fp/s_fdiv.c
  59 index 341339f5ed..7a15cbeee6 100644
  60 --- a/sysdeps/ieee754/soft-fp/s_fdiv.c
  61 +++ b/sysdeps/ieee754/soft-fp/s_fdiv.c
  62 @@ -25,6 +25,16 @@
  63  #undef fdivl
  64
  65  #include <math-narrow.h>
  66 +#include <libc-diag.h>
  67 +
  68 +/* R_f[01] are not set in cases where they are not used in packing,
  69 +   but the compiler does not see that they are set in all cases where
  70 +   they are used, resulting in warnings that they may be used
  71 +   uninitialized.  The location of the warning differs in different
  72 +   versions of GCC, it may be where R is defined using a macro or it
  73 +   may be where the macro is defined.  This happens only with -O1.  */
  74 +DIAG_PUSH_NEEDS_COMMENT;
  75 +DIAG_IGNORE_NEEDS_COMMENT (8, "-Wmaybe-uninitialized");
  76  #include <soft-fp.h>
  77  #include <single.h>
  78  #include <double.h>
  79 @@ -53,4 +63,6 @@ __fdiv (double x, double y)
  80    CHECK_NARROW_DIV (ret, x, y);
  81    return ret;
  82  }
  83 +DIAG_POP_NEEDS_COMMENT;
  84 +
  85  libm_alias_float_double (div)
  86 --
  87 2.17.0
  88