[Bug tree-optimization/80359] [7 Regression] DSE causes error: invalid reference prefix

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=80359

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Priority|P3                          |P1
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2017-04-09
                 CC|                            |law at gcc dot gnu.org
   Target Milestone|---                         |7.0
            Summary|-O3 causes error: invalid   |[7 Regression] DSE causes
                   |reference prefix            |error: invalid reference
                   |                            |prefix
     Ever confirmed|0                           |1

--- Comment #3 from Richard Biener <rguenth at gcc dot gnu.org> ---
(gdb) p t
$1 = <target_mem_ref 0x7ffff68b5e40>

indeed we may not subset TMRs.  Caused by DSE (Jeffs improvements).

Note the particular TMR (just base and constant offset) could be rewritten
to a regular MEM_REF.