https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101521
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
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CC| |jakub at gcc dot gnu.org
--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
Note, -fsanitize=undefined -fsanitize-undefined-trap-on-error actually doesn't
use IFN_{ADD,SUB,MUL}_OVERFLOW, those are used for the __builtin_*_overflow*
builtins, but its own IFN_UBSAN_CHECK_{ADD,SUB,MUL} ones.
Those are for the IL simpler than IFN_{ADD,SUB,MUL}_OVERFLOW, they just return
their value instead of _Complex containing both the value and overflow flag -
the abort operation (whether __builtin_trap () or some libubsan API call) is
implicit in it.
I think best would be to introduce for -ftrapv another set of ifns, and treat
those mostly as IFN_UBSAN_CHECK_{ADD,SUB,MUL}, except that the abort operation
would be always __builtin_trap regardless of
-f{,no-}sanitize-undefined-trap-on-error and perhaps the expansion could at
least for -Os or for longer sequences try to use the existing libgcc APIs when
they are available.
Negate is for ubsan handled as IFN_UBSAN_CHECK_SUB (0, x), yes, division would
need a new ifn.
