[Bug rtl-optimization/100263] [11/12 Regression] RTL optimizers miscompile loop

[ebotcazou at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100263

--- Comment #10 from Eric Botcazou <ebotcazou at gcc dot gnu.org> ---
> Shouldn't we rather check for REG_CAN_CHANGE_MODE_P? A check for
> TARGET_HARD_REGNO_MODE_OK for a FP register and QImode is successful.

OK, then it's probably better to add it to:

      if (!is_a <scalar_int_mode> (reg_mode[regno], &old_mode)
          || !MODES_OK_FOR_MOVE2ADD (mode, old_mode))
        return false;