[Bug target/120294] Missed DCE with xor when emulating __builtin_ctzg() with __builtin_ctz() and bitshift

[mcccs at gmx dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=120294

--- Comment #1 from mcccs at gmx dot com ---
pr95861 was also closed - there was a bug in intel hardware that caused
dependency detection false positive, so it would be slow without the xor