[Bug tree-optimization/117927] [15 Regression] Invalid rotate optimization

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=117927

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
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                 CC|                            |jakub at gcc dot gnu.org

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
So
--- gcc/match.pd.jj     2024-12-05 18:29:46.246399098 +0100
+++ gcc/match.pd        2024-12-06 09:38:35.670473040 +0100
@@ -4981,7 +4981,8 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
      orotate (rrotate lrotate)
  (simplify
   (rotate @0 (minus INTEGER_CST@1 @2))
-   (if (element_precision (TREE_TYPE (@0)) == wi::to_wide (@1))
+   (if (element_precision (TREE_TYPE (@0)) == wi::to_wide (@1)
+        && tree_expr_nonzero_p (@2))
      (orotate @0 @2))))

 /* Turn (a OP c1) OP c2 into a OP (c1+c2).  */
plus adjust the testcase?
And I think we want to extend the r15-5635, r15-5657, r15-5731 changes to
rotates as well.