[Bug tree-optimization/94130] [8/9/10 Regression] Unintended result with optimization option when assigning two structures, memset and 0

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=94130

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |law at gcc dot gnu.org,
                   |                            |rguenth at gcc dot gnu.org
             Status|UNCONFIRMED                 |NEW
   Target Milestone|---                         |8.5
   Last reconfirmed|                            |2020-03-11
      Known to work|                            |6.5.0
     Ever confirmed|0                           |1
           Priority|P3                          |P2
            Summary|Unintended result with      |[8/9/10 Regression]
                   |optimization option when    |Unintended result with
                   |assigning two structures,   |optimization option when
                   |memset and 0                |assigning two structures,
                   |                            |memset and 0
      Known to fail|                            |7.5.0, 8.3.0, 9.2.0

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
Confirmed.  DSE prunes the memset from the wrong side it seems.  Jeff?

Breaks with -O -fno-inline already, fixed with -fno-tree-dse.