[Bug ada/116933] Ada FE incompatible with -ftrivial-auto-var-init=zero (__builtin_clear_padding not folded)

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116933

--- Comment #2 from Sam James <sjames at gcc dot gnu.org> ---
I think this is a secondary problem (tell me if I should file a new PR), but we
blow up w/ DEFERRED_INIT at -O1:
```
gnatlink hello.ali -ftrivial-auto-var-init=zero -O1
/usr/lib/gcc/x86_64-pc-linux-gnu/15/adainclude/s-secsta.ads: In function
‘system.secondary_stack.ss_stackIP’:
/usr/lib/gcc/x86_64-pc-linux-gnu/15/adainclude/s-secsta.ads:279:9: error:
location references block not in block tree
&"_init"[0]
SR.41_9 = .DEFERRED_INIT (8, 2, &"_init"[0]);
during GIMPLE pass: einline
+===========================GNAT BUG DETECTED==============================+
| 15.0.0 20241001 (experimental) f72b1a44ff582041b02d5abe0a6c8556057e6183
(x86_64-pc-linux-gnu) GCC error:|
| verify_gimple failed                                                     |
| Error detected around
/usr/lib/gcc/x86_64-pc-linux-gnu/15/adainclude/s-secsta.ads:279:9|
| Compiling /home/sam/build/ada/b~hello.adb                                |
```