[Bug tree-optimization/126257] [16/17 Regression] wrong code at -O2/3 with _BitInt(2) since r16-5324

[jakub at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126257

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
It is
/* Convert x+x into x*2.  */
(simplify
 (plus @0 @0)
 (if (SCALAR_FLOAT_TYPE_P (type))
  (mult @0 { build_real (type, dconst2); })
  (if (INTEGRAL_TYPE_P (type))
   (mult @0 { build_int_cst (type, 2); }))))
in match.pd.
We need TYPE_PRECISION (type) > (2 - TYPE_UNSIGNED (type)).