[Bug rtl-optimization/81423] [6/7/8 Regression] Wrong code at -O2

[ubizjak at gmail dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=81423

Uroš Bizjak <ubizjak at gmail dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|tree-optimization           |rtl-optimization

--- Comment #2 from Uroš Bizjak <ubizjak at gmail dot com> ---
The referred commit enabled new extzv<mode> and insv<mode> patterns, and in the
past, it exposed a bunch of bugs in the generic RTL part.

Let me analyse what is going on here.