[Bug tree-optimization/82224] Strict-aliasing not noticing valid aliasing of two unions with active members

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

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82224

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           See Also|                            |https://gcc.gnu.org/bugzill
                   |                            |a/show_bug.cgi?id=101641

--- Comment #15 from Richard Biener <rguenth at gcc dot gnu.org> ---
This is similar to PR101641, FRE1 (and other passes if you disable that) elide
the seemingly redundant stores which activate another union member.

   temp_11 = p3_10(D)->v1.x;
-  p3_10(D)->v2.x = temp_11;
   MEM[(struct s2 *)p2_13(D)].x = 1234;
   temp_15 = p3_10(D)->v2.x;
-  p3_10(D)->v1.x = temp_15;