[Bug tree-optimization/78902] Missed malloc optimizations: malloc w/o LHS and zero argument

[glisse at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78902

--- Comment #2 from Marc Glisse <glisse at gcc dot gnu.org> ---
The p=malloc(0) transformation looks strange.
(I never know if we are supposed to unlink_stmt_vdef, etc)