diff options
| -rw-r--r-- | gcc/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/tree-vrp.c | 29 |
2 files changed, 27 insertions, 7 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 1bdc306..d26d9be 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,8 @@ +2007-03-11 Ian Lance Taylor <iant@google.com> + + * tree-vrp.c (vrp_int_const_binop): Handle PLUS_EXPR and + the *_DIV_EXPR codes correctly with overflow infinities. + 2007-03-11 Ira Rosen <irar@il.ibm.com> * tree-data-ref.c (analyze_offset): Add a return value (bool) to diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index dcb5f6a..d3fd911 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -1519,15 +1519,26 @@ vrp_int_const_binop (enum tree_code code, tree val1, tree val2) && !supports_overflow_infinity (TREE_TYPE (res))) return NULL_TREE; - /* We have to punt on subtracting infinities of the same sign, - since we can't tell what the sign of the result should - be. */ - if (code == MINUS_EXPR - && sgn1 == sgn2 + /* We have to punt on adding infinities of different signs, + since we can't tell what the sign of the result should be. + Likewise for subtracting infinities of the same sign. */ + if (((code == PLUS_EXPR && sgn1 != sgn2) + || (code == MINUS_EXPR && sgn1 == sgn2)) && is_overflow_infinity (val1) && is_overflow_infinity (val2)) return NULL_TREE; + /* Don't try to handle division or shifting of infinities. */ + if ((code == TRUNC_DIV_EXPR + || code == FLOOR_DIV_EXPR + || code == CEIL_DIV_EXPR + || code == EXACT_DIV_EXPR + || code == ROUND_DIV_EXPR + || code == RSHIFT_EXPR) + && (is_overflow_infinity (val1) + || is_overflow_infinity (val2))) + return NULL_TREE; + /* Notice that we only need to handle the restricted set of operations handled by extract_range_from_binary_expr. Among them, only multiplication, addition and subtraction @@ -1541,8 +1552,12 @@ vrp_int_const_binop (enum tree_code code, tree val1, tree val2) if ((code == MULT_EXPR && sgn1 == sgn2) /* For addition, the operands must be of the same sign to yield an overflow. Its sign is therefore that - of one of the operands, for example the first. */ - || (code == PLUS_EXPR && sgn1 > 0) + of one of the operands, for example the first. For + infinite operands X + -INF is negative, not positive. */ + || (code == PLUS_EXPR + && (sgn1 >= 0 + ? !is_negative_overflow_infinity (val2) + : is_positive_overflow_infinity (val2))) /* For subtraction, non-infinite operands must be of different signs to yield an overflow. Its sign is therefore that of the first operand or the opposite of |