[gcc r14-1618] match.pd: Improve zero_one_valued_p

[Jakub Jelinek]

https://gcc.gnu.org/g:e2ebd22acac844ba74e69a34dbf064d41d102cc1

commit r14-1618-ge2ebd22acac844ba74e69a34dbf064d41d102cc1
Author: Jakub Jelinek <jakub@redhat.com>
Date:   Wed Jun 7 19:18:26 2023 +0200

    match.pd: Improve zero_one_valued_p
    
    Recently zero_one_valued_p was changed to handle integer_zerop
    case specially, because tree_nonzero_bits (@0) == 1 only returns
    true for non-constant values with range [0, 1] or constant 1,
    constant 0 has tree_nonzero_bits (integer_zero_node) == 0.
    
    The following patch reverts that change and instead checks
    that tree_nonzero_bits is <= 1U.
    
    2023-06-07  Jakub Jelinek  <jakub@redhat.com>
    
            * match.pd (zero_one_valued_p): Don't handle integer_zerop specially,
            instead compare tree_nonzero_bits <= 1U rather than just == 1.

Diff:
---
 gcc/match.pd | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index dc36927cd0f..fd32389decf 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -1984,15 +1984,12 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   @0)
 
 /* zero_one_valued_p will match when a value is known to be either
-   0 or 1 including the constant 0. */
+   0 or 1 including constants 0 or 1. */
 (match zero_one_valued_p
  @0
- (if (INTEGRAL_TYPE_P (type) && tree_nonzero_bits (@0) == 1)))
+ (if (INTEGRAL_TYPE_P (type) && wi::leu_p (tree_nonzero_bits (@0), 1))))
 (match zero_one_valued_p
  truth_valued_p@0)
-(match zero_one_valued_p
- integer_zerop@0
- (if (INTEGRAL_TYPE_P (type))))
 
 /* Transform { 0 or 1 } * { 0 or 1 } into { 0 or 1 } & { 0 or 1 }.  */
 (simplify