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| author | Bernd Edlinger <bernd.edlinger@hotmail.de> | 2017-12-19 18:41:01 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2017-12-19 18:41:01 +0000 |
| commit | 648615e13f8d7b638cb911926b8bb70804217f15 (patch) | |
| tree | f2c1e2e3d031d0f4e72b982950ee5a6b9223e5a9 | |
| parent | f1e005022ebd246e1541386cd2f3286f008d2d98 (diff) | |
| download | glibc-648615e13f8d7b638cb911926b8bb70804217f15.tar.gz glibc-648615e13f8d7b638cb911926b8bb70804217f15.tar.xz glibc-648615e13f8d7b638cb911926b8bb70804217f15.zip | |
Avoid signed shift overflow in pow (bug 21309).
As noted in bug 21309, dbl-64/e_pow.c contains signed int shifts that, although the shift count is in the range [0, 31], shift bits into and beyond the sign bit and so are undefined in ISO C. Although this is defined in GNU C, this patch from the bug cleans up the code to avoid those shifts. Tested for x86_64. [BZ #21309] * sysdeps/ieee754/dbl-64/e_pow.c (checkint): Make m and n unsigned.
| -rw-r--r-- | ChangeLog | 6 | ||||
| -rw-r--r-- | sysdeps/ieee754/dbl-64/e_pow.c | 3 |
2 files changed, 8 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog index 4f836e3f67..d194a73592 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2017-12-19 Bernd Edlinger <bernd.edlinger@hotmail.de> + + [BZ #21309] + * sysdeps/ieee754/dbl-64/e_pow.c (checkint): Make m and n + unsigned. + 2017-12-19 Joseph Myers <joseph@codesourcery.com> Revert: diff --git a/sysdeps/ieee754/dbl-64/e_pow.c b/sysdeps/ieee754/dbl-64/e_pow.c index 9f6439ee42..8c7fb74549 100644 --- a/sysdeps/ieee754/dbl-64/e_pow.c +++ b/sysdeps/ieee754/dbl-64/e_pow.c @@ -452,7 +452,8 @@ checkint (double x) int4 i[2]; double x; } u; - int k, m, n; + int k; + unsigned int m, n; u.x = x; m = u.i[HIGH_HALF] & 0x7fffffff; /* no sign */ if (m >= 0x7ff00000) |