[Bug tree-optimization/66558] Missed vectorization of loop with control flow

[rsandifo at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66558

rsandifo at gcc dot gnu.org  changed:

   What|Removed |Added

 Status|UNCONFIRMED |RESOLVED
 Resolution|--- |FIXED

--- Comment #4 from rsandifo at gcc dot gnu.org  
---
Patch applied.

[Bug tree-optimization/66558] Missed vectorization of loop with control flow

[alahay01 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66558

--- Comment #3 from alahay01 at gcc dot gnu.org ---
Author: alahay01
Date: Fri Nov 13 10:51:34 2015
New Revision: 230297

URL: https://gcc.gnu.org/viewcvs?rev=230297=gcc=rev
Log:
Optimize condition reductions where the result is an integer induction variable

2015-11-13  Alan Hayward 

gcc/
PR tree-optimization/66558
* tree-vect-loop.c (is_integer_induction):Add.
(vectorizable_reduction): Add integer induction checks.

gcc/testsuite/
PR tree-optimization/66558
* gcc.dg/vect/pr65947-1.c: Add checks.
* gcc.dg/vect/pr65947-2.c: Add checks.
* gcc.dg/vect/pr65947-3.c: Add checks.
* gcc.dg/vect/pr65947-4.c: Add checks.
* gcc.dg/vect/pr65947-5.c: Add checks.
* gcc.dg/vect/pr65947-6.c: Add checks.
* gcc.dg/vect/pr65947-10.c: Add checks.
* gcc.dg/vect/pr65947-12.c: New test.
* gcc.dg/vect/pr65947-13.c: New test.


Added:
trunk/gcc/testsuite/gcc.dg/vect/pr65947-12.c
trunk/gcc/testsuite/gcc.dg/vect/pr65947-13.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/testsuite/ChangeLog
trunk/gcc/testsuite/gcc.dg/vect/pr65947-1.c
trunk/gcc/testsuite/gcc.dg/vect/pr65947-10.c
trunk/gcc/testsuite/gcc.dg/vect/pr65947-2.c
trunk/gcc/testsuite/gcc.dg/vect/pr65947-3.c
trunk/gcc/testsuite/gcc.dg/vect/pr65947-4.c
trunk/gcc/testsuite/gcc.dg/vect/pr65947-5.c
trunk/gcc/testsuite/gcc.dg/vect/pr65947-6.c
trunk/gcc/tree-vect-loop.c
trunk/gcc/tree-vectorizer.h

[Bug tree-optimization/66558] Missed vectorization of loop with control flow

[alalaw01 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66558

--- Comment #2 from alalaw01 at gcc dot gnu.org ---
This generalizes https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65947, but
vectorizing the predicate as a reduction is not sufficient here.

[Bug tree-optimization/66558] Missed vectorization of loop with control flow

[alalaw01 at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=66558

--- Comment #1 from alalaw01 at gcc dot gnu.org ---
Strategy could be similar to https://gcc.gnu.org/bugzilla/show_bug.cgi?id=54013
except finding the last bit rather than the first (and no jump out of the
loop).

That is, in the loop body:

  v_pred = (a[i]  threshold) for each element
  if (any element of v_pred set)
v_save_pred = v_pred
v_save_i = {i, i+1, i+2, i+3}
v_last = v_save_i // or a different expression, as is assigned to 'last'

and in the epilogue,

  last = v_last[ rightmost set element in v_save_pred ]

where the rightmost set element could be done via narrow/trunc and 'bsr' (on
x86), or more generally,

  idx = reduc_max_expr (v_save_pred ? v_save_i : 0)
  // any reduction will do here, as only one element will be non-zero:
  last = reduc_max_expr (v_save_i == idx ? v_last : 0)
  // or alternatively:
  last = v_last[ idx  (vec_num_elts - 1) ]