| Message ID | 20250425205618.360232-4-adhemerval.zanella@linaro.org |
|---|---|
| State | Accepted |
| Commit | de0c4adf94a379873c0167f792519e91df28c3ed |
| Headers | show |
| Series | Fix UB in math implementations | expand |
On 4/25/25 4:54 PM, Adhemerval Zanella wrote: > The left shift overflows for 'int', use a literal instead. It syncs > with OPTIMIZED-ROUTINES commit 0f87f607b976820ef41fe64d004fe67dc7af8236. > > Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. LGTM. Reviewed-by: Carlos O'Donell <carlos@redhat.com> > --- > sysdeps/ieee754/flt-32/e_logf.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/sysdeps/ieee754/flt-32/e_logf.c b/sysdeps/ieee754/flt-32/e_logf.c > index 6a595cf7f0..207151c76a 100644 > --- a/sysdeps/ieee754/flt-32/e_logf.c > +++ b/sysdeps/ieee754/flt-32/e_logf.c > @@ -70,7 +70,7 @@ __logf (float x) > tmp = ix - OFF; > i = (tmp >> (23 - LOGF_TABLE_BITS)) % N; > k = (int32_t) tmp >> 23; /* arithmetic shift */ > - iz = ix - (tmp & 0x1ff << 23); > + iz = ix - (tmp & 0xff800000); > invc = T[i].invc; > logc = T[i].logc; > z = (double_t) asfloat (iz); OK, confirmed from git@github.com:ARM-software/optimized-routines.git commit 0f87f607b976820ef41fe64d004fe67dc7af8236 Author: Joe Ramsay <Joe.Ramsay@arm.com> Date: Thu Jan 5 11:56:20 2023 +0000 Rewrite two abs masks as literals These were technically undefined behaviour - they have been rewritten without the shift so that their type is unsigned int by default.
diff --git a/sysdeps/ieee754/flt-32/e_logf.c b/sysdeps/ieee754/flt-32/e_logf.c index 6a595cf7f0..207151c76a 100644 --- a/sysdeps/ieee754/flt-32/e_logf.c +++ b/sysdeps/ieee754/flt-32/e_logf.c @@ -70,7 +70,7 @@ __logf (float x) tmp = ix - OFF; i = (tmp >> (23 - LOGF_TABLE_BITS)) % N; k = (int32_t) tmp >> 23; /* arithmetic shift */ - iz = ix - (tmp & 0x1ff << 23); + iz = ix - (tmp & 0xff800000); invc = T[i].invc; logc = T[i].logc; z = (double_t) asfloat (iz);