https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78902
--- Comment #8 from rguenther at suse dot de <rguenther at suse dot de> --- On December 22, 2016 5:36:56 PM GMT+01:00, "msebor at gcc dot gnu.org" <gcc-bugzi...@gcc.gnu.org> wrote: >https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78902 > >Martin Sebor <msebor at gcc dot gnu.org> changed: > > What |Removed |Added >---------------------------------------------------------------------------- > CC| |msebor at gcc dot gnu.org > >--- Comment #6 from Martin Sebor <msebor at gcc dot gnu.org> --- >Warning on malloc with an unused return value sounds like a good idea >to me (in >fact, it seems that all allocation functions to be declared with >warn_unused_result; i.e., all those declared with attribute >alloc_size). > >I also think warning on malloc(0) can be useful. GCC 7 has >-Walloc-zero that >warns on all zero-size allocations. Unfortunately, it's not in -Wall >or >-Wextra and has to be explicitly enabled. > >Unconditionally turning malloc(0) into NULL wouldn't be safe since the >call is >allowed to return a unique non-null pointer and there are >implementations >(e.g., Glibc) that do return one. But doing that under an option might >be >useful on targets where the system malloc returns null (though it could >break >with superimposition). > >I'm not sure that eliminating calls to malloc whose return value is >unused is a >safe optimization. Malloc can be superimposed and the replacement >version >might have important side-effects that the optimization would prevent. Given we remove malloc/free pairs it might be OK I think.
