[Bug tree-optimization/46008] New: Floating point condexpr not vectorized

[Bug tree-optimization/46008] New: Floating point condexpr not vectorized

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46008

           Summary: Floating point condexpr not vectorized
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: jakub@gcc.gnu.org
                CC: irar@gcc.gnu.org


void bar (double *);
void foo (double *a, double *b, double *c, double *d)
{
  double e[1024], f;
  int i;

  for (i = 0; i < 1024; i++)
    e[i] = (f = a[i] + b[i] + c[i] * d[i]) < 0.0 ? 3.0 : f;
  bar (e);
}

is not vectorized at -O3 (is at -O3 -ffast-math though).
One problem is in ifcvt, which creates bogus dead stmts with bool type, but
even with that fixed the vectorizer gives up.
I'll attach ifcvt fix, is there something that can be done about this on the
vectorizer side?

[Bug tree-optimization/46008] Floating point condexpr not vectorized

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46008

--- Comment #1 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-10-13 16:19:27 UTC ---
Created attachment 22031
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=22031
gcc46-pr46008.patch

The ifcvt fix (untested).  Still the vectorizer gives up, because the floating
point comparison is first computed into a _Bool/bool variable which is then
(with a single immediate use) immediately used in the following COND_EXPR.

[Bug tree-optimization/46008] Floating point condexpr not vectorized

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46008

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2010-10-14 19:34:20 UTC ---
Author: jakub
Date: Thu Oct 14 19:34:16 2010
New Revision: 165476

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=165476
Log:
    PR tree-optimization/46008
    * tree-if-conv.c (predicate_bbs): Try to canonicalize c2
    if possible.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-if-conv.c

[Bug tree-optimization/46008] Floating point condexpr not vectorized

[pinskia at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46008

Andrew Pinski <pinskia at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-03-13
     Ever Confirmed|0                           |1
           Severity|normal                      |enhancement

--- Comment #3 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-03-13 23:16:29 UTC ---
I think there was some talk about changing COND_EXPR not to have a comparison
as the first operand.