[Bug bootstrap/86629] New: error: 'alloca' bound is unknown breaks bootstrap

[kargl at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=86629

            Bug ID: 86629
           Summary: error: 'alloca' bound is unknown breaks bootstrap
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: bootstrap
          Assignee: unassigned at gcc dot gnu.org
          Reporter: kargl at gcc dot gnu.org
  Target Milestone: ---

In file included from ../../gcc/gcc/system.h:691,
                 from ../../gcc/gcc/tree-vect-slp.c:23:
../../gcc/gcc/tree-vect-slp.c: In function '_slp_tree*
vect_build_slp_tree_2(vec_info*, vec<gimple*>, unsigned int, poly_uint64*,
vec<_slp_tree*>*, bool*, unsigned int*, unsigned int*, unsigned int)':
../../gcc/gcc/../include/libiberty.h:722:36: error: 'alloca' bound is unknown
[-Werror=alloca-larger-than=]
 # define alloca(x) __builtin_alloca(x)
                    ~~~~~~~~~~~~~~~~^~~
../../gcc/gcc/../include/libiberty.h:356:33: note: in expansion of macro
'alloc'
 #define XALLOCAVEC(T, N) ((T *) alloca (sizeof (T) * (N)))
                                 ^~~~~~
../../gcc/gcc/tree-vect-slp.c:1437:16: note: in expansion of macro 'XALLOCAVEC'
    bool *tem = XALLOCAVEC (bool, group_size);
                ^~~~~~~~~~
cc1plus: all warnings being treated as errors
gmake[3]: *** [Makefile:1112: tree-vect-slp.o] Error 1
gmake[3]: Leaving directory '/usr/home/kargl/gcc/obj/gcc'
gmake[2]: *** [Makefile:4644: all-stage2-gcc] Error 2
gmake[2]: Leaving directory '/usr/home/kargl/gcc/obj'
gmake[1]: *** [Makefile:22925: stage2-bubble] Error 2
gmake[1]: Leaving directory '/usr/home/kargl/gcc/obj'
gmake: *** [Makefile:949: all] Error 2