[Bug middle-end/126153] [13/14/15/16/17 Regression] [csmith] runtime crash with -O3 -ftrivial-auto-var-init=zero

[rguenth at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126153

--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> ---
On the original testcase we can see we fall out of main(), but only with
-ftrivial-auto-var-init=zero.

Somehow the #pragma pack(1) on S0 is the trigger.