diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 118 |
1 files changed, 111 insertions, 7 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index f559fff..00fd134 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3776,7 +3776,7 @@ make_range (tree exp, int *pin_p, tree *plow, tree *phigh) /* Given a range, LOW, HIGH, and IN_P, an expression, EXP, and a result type, TYPE, return an expression to test if EXP is in (or out of, depending - on IN_P) the range. */ + on IN_P) the range. Return 0 if the test couldn't be created. */ static tree build_range_check (tree type, tree exp, int in_p, tree low, tree high) @@ -3784,9 +3784,14 @@ build_range_check (tree type, tree exp, int in_p, tree low, tree high) tree etype = TREE_TYPE (exp); tree value; - if (! in_p - && (0 != (value = build_range_check (type, exp, 1, low, high)))) - return invert_truthvalue (value); + if (! in_p) + { + value = build_range_check (type, exp, 1, low, high); + if (value != 0) + return invert_truthvalue (value); + + return 0; + } if (low == 0 && high == 0) return fold_convert (type, integer_one_node); @@ -3842,8 +3847,39 @@ build_range_check (tree type, tree exp, int in_p, tree low, tree high) } } - if (0 != (value = const_binop (MINUS_EXPR, high, low, 0)) - && ! TREE_OVERFLOW (value)) + value = const_binop (MINUS_EXPR, high, low, 0); + if (value != 0 && TREE_OVERFLOW (value) && ! TYPE_UNSIGNED (etype)) + { + tree utype, minv, maxv; + + /* Check if (unsigned) INT_MAX + 1 == (unsigned) INT_MIN + for the type in question, as we rely on this here. */ + switch (TREE_CODE (etype)) + { + case INTEGER_TYPE: + case ENUMERAL_TYPE: + case CHAR_TYPE: + utype = lang_hooks.types.unsigned_type (etype); + maxv = fold_convert (utype, TYPE_MAX_VALUE (etype)); + maxv = range_binop (PLUS_EXPR, NULL_TREE, maxv, 1, + integer_one_node, 1); + minv = fold_convert (utype, TYPE_MIN_VALUE (etype)); + if (integer_zerop (range_binop (NE_EXPR, integer_type_node, + minv, 1, maxv, 1))) + { + etype = utype; + high = fold_convert (etype, high); + low = fold_convert (etype, low); + exp = fold_convert (etype, exp); + value = const_binop (MINUS_EXPR, high, low, 0); + } + break; + default: + break; + } + } + + if (value != 0 && ! TREE_OVERFLOW (value)) return build_range_check (type, fold (build2 (MINUS_EXPR, etype, exp, low)), 1, fold_convert (etype, integer_zero_node), @@ -3973,7 +4009,75 @@ merge_ranges (int *pin_p, tree *plow, tree *phigh, int in0_p, tree low0, 1, low1, 0))) in_p = 0, low = low0, high = high1; else - return 0; + { + /* Canonicalize - [min, x] into - [-, x]. */ + if (low0 && TREE_CODE (low0) == INTEGER_CST) + switch (TREE_CODE (TREE_TYPE (low0))) + { + case ENUMERAL_TYPE: + if (TYPE_PRECISION (TREE_TYPE (low0)) + != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (low0)))) + break; + /* FALLTHROUGH */ + case INTEGER_TYPE: + case CHAR_TYPE: + if (tree_int_cst_equal (low0, + TYPE_MIN_VALUE (TREE_TYPE (low0)))) + low0 = 0; + break; + case POINTER_TYPE: + if (TYPE_UNSIGNED (TREE_TYPE (low0)) + && integer_zerop (low0)) + low0 = 0; + break; + default: + break; + } + + /* Canonicalize - [x, max] into - [x, -]. */ + if (high1 && TREE_CODE (high1) == INTEGER_CST) + switch (TREE_CODE (TREE_TYPE (high1))) + { + case ENUMERAL_TYPE: + if (TYPE_PRECISION (TREE_TYPE (high1)) + != GET_MODE_BITSIZE (TYPE_MODE (TREE_TYPE (high1)))) + break; + /* FALLTHROUGH */ + case INTEGER_TYPE: + case CHAR_TYPE: + if (tree_int_cst_equal (high1, + TYPE_MAX_VALUE (TREE_TYPE (high1)))) + high1 = 0; + break; + case POINTER_TYPE: + if (TYPE_UNSIGNED (TREE_TYPE (high1)) + && integer_zerop (range_binop (PLUS_EXPR, NULL_TREE, + high1, 1, + integer_one_node, 1))) + high1 = 0; + break; + default: + break; + } + + /* The ranges might be also adjacent between the maximum and + minimum values of the given type. For + - [{min,-}, x] and - [y, {max,-}] ranges where x + 1 < y + return + [x + 1, y - 1]. */ + if (low0 == 0 && high1 == 0) + { + low = range_binop (PLUS_EXPR, NULL_TREE, high0, 1, + integer_one_node, 1); + high = range_binop (MINUS_EXPR, NULL_TREE, low1, 0, + integer_one_node, 0); + if (low == 0 || high == 0) + return 0; + + in_p = 1; + } + else + return 0; + } } else if (subset) in_p = 0, low = low0, high = high0; |