| Message ID | 20250425205618.360232-2-adhemerval.zanella@linaro.org |
|---|---|
| State | Accepted |
| Commit | 92f7b6061d867c5e5f26e84c44a3ec2887bf6c81 |
| 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 unsigned instead. It syncs > with CORE-MATH commit 4d6192d2. > > Checked on aarch64-linux-gnu, x86_64-linux-gnu, and i686-linux-gnu. LGTM. Note upstream CORE-MATH uses 1UL here not 1U. Still OK. Reviewed-by: Carlos O'Donell <carlos@redhat.com> > --- > sysdeps/ieee754/flt-32/e_atanhf.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/sysdeps/ieee754/flt-32/e_atanhf.c b/sysdeps/ieee754/flt-32/e_atanhf.c > index 5138408324..eeb1aae6a1 100644 > --- a/sysdeps/ieee754/flt-32/e_atanhf.c > +++ b/sysdeps/ieee754/flt-32/e_atanhf.c > @@ -3,7 +3,7 @@ > Copyright (c) 2023-2024 Alexei Sibidanov. > > The original version of this file was copied from the CORE-MATH > -project (file src/binary32/acosh/acoshf.c, revision bc385c2). > +project (file src/binary32/acosh/acoshf.c, revision 4d6192d2). > > Permission is hereby granted, free of charge, to any person obtaining a copy > of this software and associated documentation files (the "Software"), to deal > @@ -135,7 +135,7 @@ __ieee754_atanhf (float x) > } > double sgn = s[ux >> 31]; > unsigned int e = ax >> 24; > - unsigned int md = ((ux << 8) | 1 << 31) >> (126 - e); > + unsigned int md = ((ux << 8) | 1U << 31) >> (126 - e); OK. We use 1U, but CORE-MATH uses 1UL, so it doesn't *quite* sync, but close enough. > unsigned int mn = -md; > int nz = __builtin_clz (mn) + 1; > mn <<= nz; OK. commit 4d6192d21a311e412b8cc76bd33c7ba4d41ccbab Author: Paul Zimmermann <Paul.Zimmermann@inria.fr> Date: Thu Mar 13 13:38:38 2025 +0100 [atanhf] fixed undefined behavior
diff --git a/sysdeps/ieee754/flt-32/e_atanhf.c b/sysdeps/ieee754/flt-32/e_atanhf.c index 5138408324..eeb1aae6a1 100644 --- a/sysdeps/ieee754/flt-32/e_atanhf.c +++ b/sysdeps/ieee754/flt-32/e_atanhf.c @@ -3,7 +3,7 @@ Copyright (c) 2023-2024 Alexei Sibidanov. The original version of this file was copied from the CORE-MATH -project (file src/binary32/acosh/acoshf.c, revision bc385c2). +project (file src/binary32/acosh/acoshf.c, revision 4d6192d2). Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal @@ -135,7 +135,7 @@ __ieee754_atanhf (float x) } double sgn = s[ux >> 31]; unsigned int e = ax >> 24; - unsigned int md = ((ux << 8) | 1 << 31) >> (126 - e); + unsigned int md = ((ux << 8) | 1U << 31) >> (126 - e); unsigned int mn = -md; int nz = __builtin_clz (mn) + 1; mn <<= nz;