[patch] gcc.dg/analyzer tests: relax dependency on alloca.h

[Alexandre Oliva]

Hello, Olivier,

On Dec 18, 2020, Olivier Hainque <hainque@adacore.com> wrote:

> Ping for https://gcc.gnu.org/pipermail/gcc-patches/2020-October/557548.html
> (copied below for convenience), please ?

I think defining alloca as a macro in analyzer-alloca.h might conflict
with system headers included before or after analyzer-alloca.h

Say, if a system header #defines alloca(n), GCC might warn when
encountering a different #define in analyzer-alloca.h, included later.

OTOH, if analyzer-alloca.h is included first, then a later system header
that attempts to declare alloca as a function could be macro-substituted
into declaring __builtin_alloca, which probably wouldn't end well.

While the alloca macro would render other changes from alloca to
__builtin_alloca unnecessary, there's such an explicit change in the
patch.

If it were up to me, I'd rather use __builtin_alloca explicitly all
over.  I think we already do that in several other tests, for similar
reasons (that some target systems don't have alloca.h or alloca)

Would you mind if I submitted an alternate patch to do so?

-- 
Alexandre Oliva, happy hacker  https://FSFLA.org/blogs/lxo/
   Free Software Activist         GNU Toolchain Engineer
        Vim, Vi, Voltei pro Emacs -- GNUlius Caesar