[Bug middle-end/86631] [9 Regression] missing -Walloc-size-larger-than on ILP32 hosts

[joseph at codesourcery dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86631

--- Comment #1 from joseph at codesourcery dot com <joseph at codesourcery dot com> ---
On Sun, 22 Jul 2018, msebor at gcc dot gnu.org wrote:

> In ILP32 it sets the limit for the warning to LLONG_MAX which is greater than
> the value of PTRDIFF_MAX on the targer (the intended setting).   Unless there
> is a macro that on the hosts gives the corresponding limit it might be
> necessary to either reserve a value as special (such as HOST_WIDE_INT_MAX), or
> to enhance the option argument parser to recognize and interpret such macros so
> that Walloc-size-larger-than=PTRDIFF_MAX can be set in c.opt and interpreted to
> mean the same thing regardless of the target.

Note that target PTRDIFF_MAX may depend on architecture-specific 
command-line options, so you'd need to make sure the initialization 
ordering is correct (target options processed and built-in types 
registered, so that it's possible to look up PTRDIFF_TYPE by name and so 
find out its max value).