Re: [gimple-isel] Remove redundant if condition

[Richard Biener <richard.guenther@gmail.com>]

On Tue, Oct 5, 2021 at 9:11 AM Prathamesh Kulkarni via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Hi,
> In gimple_expand_vec_cond_expr:
>
>   icode = get_vcond_icode (mode, cmp_op_mode, unsignedp);
>   if (icode == CODE_FOR_nothing)
>     {
>       if (tcode == LT_EXPR
>           && op0a == op0)
>         {
>           /* A VEC_COND_EXPR condition could be folded from EQ_EXPR/NE_EXPR
>              into a constant when only get_vcond_eq_icode is supported.
>              Try changing it to NE_EXPR.  */
>           tcode = NE_EXPR;
>         }
>       if ((tcode == EQ_EXPR || tcode == NE_EXPR)
>           && direct_internal_fn_supported_p (IFN_VCONDEQ, TREE_TYPE (lhs),
>                                              TREE_TYPE (op0a),
>                                              OPTIMIZE_FOR_BOTH))
>         {
>           tree tcode_tree = build_int_cst (integer_type_node, tcode);
>           return gimple_build_call_internal (IFN_VCONDEQ, 5, op0a, op0b, op1,
>                                              op2, tcode_tree);
>         }
>     }
>
>   if (icode == CODE_FOR_nothing)
>     {
>       gcc_assert (VECTOR_BOOLEAN_TYPE_P (TREE_TYPE (op0))
>                   && can_compute_op0
>                   && (get_vcond_mask_icode (mode, TYPE_MODE (TREE_TYPE (op0)))
>                       != CODE_FOR_nothing));
>       return gimple_build_call_internal (IFN_VCOND_MASK, 3, op0, op1, op2);
>     }
>
> It seems the second check for icode == COND_FOR_nothing is redundant,
> since icode is not reassigned in the previous block ?
> The attached patch removes the second if condition.
> OK to commit after bootstrap+test ?
>
OK.

> Thanks,
> Prathamesh