[Bug tree-optimization/101639] vectorization with bool reduction

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101639

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

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Blocks|                            |53947
   Last reconfirmed|                            |2021-07-27
             Status|UNCONFIRMED                 |NEW
     Ever confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> ---
vectorizable_reduction fails the

6692      scalar_dest = gimple_assign_lhs (stmt);
6693      scalar_type = TREE_TYPE (scalar_dest);
6694      if (!POINTER_TYPE_P (scalar_type) && !INTEGRAL_TYPE_P (scalar_type)
6695          && !SCALAR_FLOAT_TYPE_P (scalar_type))
6696        return false;
6697
6698      /* Do not try to vectorize bit-precision reductions.  */
6699      if (!type_has_mode_precision_p (scalar_type))
6700        return false;

check.  I guess we could relax that for BIT_*_EXPR reductions.  But then
we run into

t5.c:4:21: note:   vect_is_simple_use: vectype vector(16) unsigned char
t5.c:4:21: missed:   mixed mask and nonmask vector types
t5.c:1:6: missed:   not vectorized: relevant stmt not supported: _7 = _4 &
r_14;
t5.c:4:21: missed:  bad operation or unsupported loop bound.

I guess that's mainly a fault of missed bool pattern handling of the
reduction - we fail to make p[i] != 0 available as non-boolean vector.


Referenced Bugs:

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=53947
[Bug 53947] [meta-bug] vectorizer missed-optimizations