https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91169
--- Comment #6 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
The compiler doesn't correct deal with index -1 in a CONSTRUCTOR after:
2019-07-12 Richard Biener <rguent...@suse.de>
* fold-const.h (get_array_ctor_element_at_index): Adjust.
* fold-const.c (get_array_ctor_element_at_index): Add
ctor_idx output parameter informing the caller where in
the constructor the element was (not) found. Add early exit
for when the ctor is sorted.
* gimple-fold.c (fold_array_ctor_reference): Support constant
folding across multiple array elements.
