[Bug middle-end/108278] [13 Regression] runtime error with -O1 -Wall

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=108278

--- Comment #17 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
We know the commit introduced UB on the compiler side, but what I don't
understand is why it triggered on the testcases you've provided.  It surely
introduced UB when compiling libgcc/unwind-dw2.c or during predefining macros
with -fbuilding-libgcc, but I think the problematic code with uninitialized
array of poly_ints could happen at different times.