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| author | Carlos O'Donell <carlos@redhat.com> | 2018-02-01 20:40:48 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2018-02-01 20:40:48 +0000 |
| commit | f1d7368196e27370dcb5dfa3319e102f33b9ad66 (patch) | |
| tree | f5cb96139f71bcacc420f32c7919fc1db97d59d8 /sysdeps/ieee754/dbl-64/s_log1p.c | |
| parent | 086ee48eaeaba871a2300daf85469671cc14c7e9 (diff) | |
| download | glibc-f1d7368196e27370dcb5dfa3319e102f33b9ad66.zip glibc-f1d7368196e27370dcb5dfa3319e102f33b9ad66.tar.gz glibc-f1d7368196e27370dcb5dfa3319e102f33b9ad66.tar.bz2 | |
Fix -Os log1p, log1pf build (bug 21314).
As reported in bug 21314, building log1p and log1pf fails with -Os
because of a spurious -Wmaybe-uninitialized warning (reported there
for GCC 5 for MIPS, I see it also with GCC 7 for x86_64). This patch,
based on the patches in the bug, fixes this using the DIAG_* macros.
Tested for x86_64 with -Os that this eliminates those warnings and so
allows the build to progress further.
2018-02-01 Carlos O'Donell <carlos@redhat.com>
Ramin Seyed-Moussavi <lordrasmus@gmail.com>
Joseph Myers <joseph@codesourcery.com>
[BZ #21314]
* sysdeps/ieee754/dbl-64/s_log1p.c: Include <libc-diag.h>.
(__log1p): Disable -Wmaybe-uninitialized for -Os around
computation using c.
* sysdeps/ieee754/flt-32/s_log1pf.c: Include <libc-diag.h>.
(__log1pf): Disable -Wmaybe-uninitialized for -Os around
computation using c.
Diffstat (limited to 'sysdeps/ieee754/dbl-64/s_log1p.c')
| -rw-r--r-- | sysdeps/ieee754/dbl-64/s_log1p.c | 12 |
1 files changed, 11 insertions, 1 deletions
diff --git a/sysdeps/ieee754/dbl-64/s_log1p.c b/sysdeps/ieee754/dbl-64/s_log1p.c index 340f637..b7cf5ce 100644 --- a/sysdeps/ieee754/dbl-64/s_log1p.c +++ b/sysdeps/ieee754/dbl-64/s_log1p.c @@ -81,6 +81,7 @@ #include <float.h> #include <math.h> #include <math_private.h> +#include <libc-diag.h> static const double ln2_hi = 6.93147180369123816490e-01, /* 3fe62e42 fee00000 */ @@ -191,5 +192,14 @@ __log1p (double x) if (k == 0) return f - (hfsq - s * (hfsq + R)); else - return k * ln2_hi - ((hfsq - (s * (hfsq + R) + (k * ln2_lo + c))) - f); + { + /* With GCC 7 when compiling with -Os the compiler warns that c + might be used uninitialized. This can't be true because k + must be 0 for c to be uninitialized and we handled that + computation earlier without using c. */ + DIAG_PUSH_NEEDS_COMMENT; + DIAG_IGNORE_Os_NEEDS_COMMENT (7, "-Wmaybe-uninitialized"); + return k * ln2_hi - ((hfsq - (s * (hfsq + R) + (k * ln2_lo + c))) - f); + DIAG_POP_NEEDS_COMMENT; + } } |