diff options
Diffstat (limited to 'gcc/fold-const.c')
| -rw-r--r-- | gcc/fold-const.c | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/gcc/fold-const.c b/gcc/fold-const.c index d5fd2a42752..7f17b89b6d3 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -3832,6 +3832,10 @@ make_range_step (location_t loc, enum tree_code code, tree arg0, tree arg1, switch (code) { case TRUTH_NOT_EXPR: + /* We can only do something if the range is testing for zero. */ + if (low == NULL_TREE || high == NULL_TREE + || ! integer_zerop (low) || ! integer_zerop (high)) + return NULL_TREE; *p_in_p = ! in_p; return arg0; @@ -3904,6 +3908,17 @@ make_range_step (location_t loc, enum tree_code code, tree arg0, tree arg1, return arg0; case NEGATE_EXPR: + /* If flag_wrapv and ARG0_TYPE is signed, make sure + low and high are non-NULL, then normalize will DTRT. */ + if (!TYPE_UNSIGNED (arg0_type) + && !TYPE_OVERFLOW_UNDEFINED (arg0_type)) + { + if (low == NULL_TREE) + low = TYPE_MIN_VALUE (arg0_type); + if (high == NULL_TREE) + high = TYPE_MAX_VALUE (arg0_type); + } + /* (-x) IN [a,b] -> x in [-b, -a] */ n_low = range_binop (MINUS_EXPR, exp_type, build_int_cst (exp_type, 0), @@ -13438,10 +13453,22 @@ fold_binary_loc (location_t loc, TREE_OPERAND (arg1, 1)), build_int_cst (TREE_TYPE (arg0), 0)); + /* Similarly for X < (cast) (1 << Y). But cast can't be narrowing, + otherwise Y might be >= # of bits in X's type and thus e.g. + (unsigned char) (1 << Y) for Y 15 might be 0. + If the cast is widening, then 1 << Y should have unsigned type, + otherwise if Y is number of bits in the signed shift type minus 1, + we can't optimize this. E.g. (unsigned long long) (1 << Y) for Y + 31 might be 0xffffffff80000000. */ if ((code == LT_EXPR || code == GE_EXPR) && TYPE_UNSIGNED (TREE_TYPE (arg0)) && CONVERT_EXPR_P (arg1) && TREE_CODE (TREE_OPERAND (arg1, 0)) == LSHIFT_EXPR + && (TYPE_PRECISION (TREE_TYPE (arg1)) + >= TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0)))) + && (TYPE_UNSIGNED (TREE_TYPE (TREE_OPERAND (arg1, 0))) + || (TYPE_PRECISION (TREE_TYPE (arg1)) + == TYPE_PRECISION (TREE_TYPE (TREE_OPERAND (arg1, 0))))) && integer_onep (TREE_OPERAND (TREE_OPERAND (arg1, 0), 0))) { tem = build2 (RSHIFT_EXPR, TREE_TYPE (arg0), arg0, |