| Message ID | 20250428170430.2030400-1-adhemerval.zanella@linaro.org |
|---|---|
| Headers | show |
| Series | Remove UB and optimize ilogbf/ilogb | expand |
On 28/04/25 14:03, Adhemerval Zanella wrote: > From a recent experiment to build glibc with -fsanitize=undefined [1], > I found that both the float and double ilogb triggered UB due to the > use of shift with a signed integer. > > This patchset fixes the UB issues on both implementations by > reimplementing with a slightly better code. > > [1] https://sourceware.org/git/?p=glibc.git;a=shortlog;h=refs/heads/azanella/ubsan-undef This version triggers some issues on loongarch and fails to build on m68k. Both architecture will need to some adjustment, I will send a v3. > > Adhemerval Zanella (4): > math: Remove UB and optimize double ilogb > math: Optimize double ilogb/llogb > math: Remove UB and optimize double ilogbf > math: Optimize float ilogb/llogb > > sysdeps/i386/fpu/math_err.c | 1 - > sysdeps/ieee754/dbl-64/e_ilogb.c | 64 +-------------------------- > sysdeps/ieee754/dbl-64/math_config.h | 2 + > sysdeps/ieee754/dbl-64/math_err.c | 32 ++++++++++++++ > sysdeps/ieee754/dbl-64/w_ilogb.c | 63 ++++++++++++++++++++++++++ > sysdeps/ieee754/dbl-64/w_llogb.c | 2 + > sysdeps/ieee754/flt-32/e_ilogbf.c | 44 +------------------ > sysdeps/ieee754/flt-32/math_config.h | 2 + > sysdeps/ieee754/flt-32/math_errf.c | 33 ++++++++++++++ > sysdeps/ieee754/flt-32/w_ilogbf.c | 66 ++++++++++++++++++++++++++++ > sysdeps/ieee754/flt-32/w_llogbf.c | 2 + > 11 files changed, 204 insertions(+), 107 deletions(-) > delete mode 100644 sysdeps/i386/fpu/math_err.c > create mode 100644 sysdeps/ieee754/dbl-64/w_ilogb.c > create mode 100644 sysdeps/ieee754/dbl-64/w_llogb.c > create mode 100644 sysdeps/ieee754/flt-32/w_ilogbf.c > create mode 100644 sysdeps/ieee754/flt-32/w_llogbf.c >