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概要[]
引数[]
- tree arg
実装[]
2959 /* Return a simplified tree node for the truth-negation of ARG. This
2960 never alters ARG itself. We assume that ARG is an operation that
2961 returns a truth value (0 or 1).
2962
2963 FIXME: one would think we would fold the result, but it causes
2964 problems with the dominator optimizer. */
2965 tree
2966 invert_truthvalue (tree arg)
2967 {
2968 tree type = TREE_TYPE (arg);
2969 enum tree_code code = TREE_CODE (arg);
2970
2971 if (code == ERROR_MARK)
2972 return arg;
2973
2974 /* If this is a comparison, we can simply invert it, except for
2975 floating-point non-equality comparisons, in which case we just
2976 enclose a TRUTH_NOT_EXPR around what we have. */
2977
2978 if (TREE_CODE_CLASS (code) == tcc_comparison)
2979 {
2980 tree op_type = TREE_TYPE (TREE_OPERAND (arg, 0));
2981 if (FLOAT_TYPE_P (op_type)
2982 && flag_trapping_math
2983 && code != ORDERED_EXPR && code != UNORDERED_EXPR
2984 && code != NE_EXPR && code != EQ_EXPR)
2985 return build1 (TRUTH_NOT_EXPR, type, arg);
2986 else
2987 {
2988 code = invert_tree_comparison (code,
2989 HONOR_NANS (TYPE_MODE (op_type)));
2990 if (code == ERROR_MARK)
2991 return build1 (TRUTH_NOT_EXPR, type, arg);
2992 else
2993 return build2 (code, type,
2994 TREE_OPERAND (arg, 0), TREE_OPERAND (arg, 1));
2995 }
2996 }
2997
2998 switch (code)
2999 {
3000 case INTEGER_CST:
3001 return constant_boolean_node (integer_zerop (arg), type);
3002
3003 case TRUTH_AND_EXPR:
3004 return build2 (TRUTH_OR_EXPR, type,
3005 invert_truthvalue (TREE_OPERAND (arg, 0)),
3006 invert_truthvalue (TREE_OPERAND (arg, 1)));
3007
3008 case TRUTH_OR_EXPR:
3009 return build2 (TRUTH_AND_EXPR, type,
3010 invert_truthvalue (TREE_OPERAND (arg, 0)),
3011 invert_truthvalue (TREE_OPERAND (arg, 1)));
3012
3013 case TRUTH_XOR_EXPR:
3014 /* Here we can invert either operand. We invert the first operand
3015 unless the second operand is a TRUTH_NOT_EXPR in which case our
3016 result is the XOR of the first operand with the inside of the
3017 negation of the second operand. */
3018
3019 if (TREE_CODE (TREE_OPERAND (arg, 1)) == TRUTH_NOT_EXPR)
3020 return build2 (TRUTH_XOR_EXPR, type, TREE_OPERAND (arg, 0),
3021 TREE_OPERAND (TREE_OPERAND (arg, 1), 0));
3022 else
3023 return build2 (TRUTH_XOR_EXPR, type,
3024 invert_truthvalue (TREE_OPERAND (arg, 0)),
3025 TREE_OPERAND (arg, 1));
3026
3027 case TRUTH_ANDIF_EXPR:
3028 return build2 (TRUTH_ORIF_EXPR, type,
3029 invert_truthvalue (TREE_OPERAND (arg, 0)),
3030 invert_truthvalue (TREE_OPERAND (arg, 1)));
3031
3032 case TRUTH_ORIF_EXPR:
3033 return build2 (TRUTH_ANDIF_EXPR, type,
3034 invert_truthvalue (TREE_OPERAND (arg, 0)),
3035 invert_truthvalue (TREE_OPERAND (arg, 1)));
3036
3037 case TRUTH_NOT_EXPR:
3038 return TREE_OPERAND (arg, 0);
3039
3040 case COND_EXPR:
3041 {
3042 tree arg1 = TREE_OPERAND (arg, 1);
3043 tree arg2 = TREE_OPERAND (arg, 2);
3044 /* A COND_EXPR may have a throw as one operand, which
3045 then has void type. Just leave void operands
3046 as they are. */
3047 return build3 (COND_EXPR, type, TREE_OPERAND (arg, 0),
3048 VOID_TYPE_P (TREE_TYPE (arg1))
3049 ? arg1 : invert_truthvalue (arg1),
3050 VOID_TYPE_P (TREE_TYPE (arg2))
3051 ? arg2 : invert_truthvalue (arg2));
3052 }
3053
3054 case COMPOUND_EXPR:
3055 return build2 (COMPOUND_EXPR, type, TREE_OPERAND (arg, 0),
3056 invert_truthvalue (TREE_OPERAND (arg, 1)));
3057
3058 case NON_LVALUE_EXPR:
3059 return invert_truthvalue (TREE_OPERAND (arg, 0));
3060
3061 case NOP_EXPR:
3062 if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE)
3063 break;
3064
3065 case CONVERT_EXPR:
3066 case FLOAT_EXPR:
3067 return build1 (TREE_CODE (arg), type,
3068 invert_truthvalue (TREE_OPERAND (arg, 0)));
3069
3070 case BIT_AND_EXPR:
3071 if (!integer_onep (TREE_OPERAND (arg, 1)))
3072 break;
3073 return build2 (EQ_EXPR, type, arg,
3074 fold_convert (type, integer_zero_node));
3075
3076 case SAVE_EXPR:
3077 return build1 (TRUTH_NOT_EXPR, type, arg);
3078
3079 case CLEANUP_POINT_EXPR:
3080 return build1 (CLEANUP_POINT_EXPR, type,
3081 invert_truthvalue (TREE_OPERAND (arg, 0)));
3082
3083 default:
3084 break;
3085 }
3086 gcc_assert (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE);
3087 return build1 (TRUTH_NOT_EXPR, type, arg);
3088 }