[Bug tree-optimization/91191] vrp and boolean arguments

rguenth at gcc dot gnu.org gcc-bugzilla@gcc.gnu.org
Thu Jul 18 07:37:00 GMT 2019


https://gcc.gnu.org/bugzilla/show_bug.cgi?id=91191

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2019-07-18
           Assignee|unassigned at gcc dot gnu.org      |rguenth at gcc dot gnu.org
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
The issue is that VRP doesn't handle the way we optimize the union punning:

  <bb 2> :
  _6 = VIEW_CONVERT_EXPR<unsigned char>(b_4(D));
  if (_6 > 1)

if we decide to rely on appropriate sign/zero-extending of sub-size precision
entities (otherwise we'd have simplified the VIEW_CONVERT to a simple
conversion) the attached fixes the missed optimzation.


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