[Bug c/124223] Cast (int32_t)0x80000000 causes the whole loop to be optimized away

[stano at meduna dot org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=124223

--- Comment #11 from stano at meduna dot org ---
I mean, the math is fine, it is undefined because of

6.3.1.3 Signed and unsigned integers
...
3. Otherwise, the new type is signed and the value cannot be represented in it;
either the result is implementation-defined or an implementation-defined signal
is raised.