Re: [PATCH 6/7] MATCH: Factor out code that for min max detection with constants

[Mikael Morin <morin-mikael@orange.fr>]

Hello,

> diff --git a/gcc/fold-const.cc b/gcc/fold-const.cc
> index 3b397ae2941..b8add24f874 100644
> --- a/gcc/fold-const.cc
> +++ b/gcc/fold-const.cc
> @@ -150,6 +150,49 @@ static tree fold_convert_const (enum tree_code, tree, tree);
>   static tree fold_view_convert_expr (tree, tree);
>   static tree fold_negate_expr (location_t, tree);
>   
> +/* This is a helper function to detect min/max for some operands of COND_EXPR.
> +   The form is "(EXP0 CMP EXP1) ? EXP2 : EXP3". */
> +tree_code
> +minmax_from_comparison (tree_code cmp, tree exp0, tree exp1, tree exp2, tree exp3)
> +{
> +  enum tree_code code = ERROR_MARK;
> +
> +  if (HONOR_NANS (exp0) || HONOR_SIGNED_ZEROS (exp0))
> +    return ERROR_MARK;
> +
> +  if (!operand_equal_p (exp0, exp2))
> +    return ERROR_MARK;
> +
> +  if (TREE_CODE (exp1) == INTEGER_CST && TREE_CODE (exp1) == INTEGER_CST

one of these conditions should probably be TREE_CODE (exp3) == INTEGER_CST?

> +      && wi::to_widest (exp1) == (wi::to_widest (exp3) - 1))
> +    {
> +      /* X <= Y - 1 equals to X < Y.  */
> +      if (cmp == LE_EXPR)
> +	code = LT_EXPR;
> +      /* X > Y - 1 equals to X >= Y.  */
> +      if (cmp == GT_EXPR)
> +	code = GE_EXPR;
> +    }
> +  if (TREE_CODE (exp3) == INTEGER_CST && TREE_CODE (exp1) == INTEGER_CST
> +      && wi::to_widest (exp1) == (wi::to_widest (exp3) + 1))
> +    {
> +     /* X < Y + 1 equals to X <= Y.  */
> +     if (cmp == LT_EXPR)
> +	code = LE_EXPR;
> +    /* X >= Y + 1 equals to X > Y.  */
> +    if (cmp == GE_EXPR)
> +	code = GT_EXPR;
> +    }


Mikael