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| author | Paul Brook <paul@codesourcery.com> | 2006-07-13 18:07:40 +0000 |
|---|---|---|
| committer | Paul Brook <paul@codesourcery.com> | 2006-07-13 18:07:40 +0000 |
| commit | a8b20def26f8819020ace682479bdf978f0cd49a (patch) | |
| tree | 681df20e561672c8cdda690cdbc48d509157afa3 /gcc/tree-vrp.c | |
| parent | 6e53ac993d70b42a4ac831c37ce23ef636c33181 (diff) | |
Merge from gcc-4_1-branch revision 114100 (gcc-4_1_1-release)
git-svn-id: https://gcc.gnu.org/svn/gcc/branches/csl/sourcerygxx-4_1@115418 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc/tree-vrp.c')
| -rw-r--r-- | gcc/tree-vrp.c | 24 |
1 files changed, 23 insertions, 1 deletions
diff --git a/gcc/tree-vrp.c b/gcc/tree-vrp.c index c00d7456fc6..84724c52e2c 100644 --- a/gcc/tree-vrp.c +++ b/gcc/tree-vrp.c @@ -1101,17 +1101,39 @@ vrp_int_const_binop (enum tree_code code, tree val1, tree val2) if (TYPE_UNSIGNED (TREE_TYPE (val1))) { int checkz = compare_values (res, val1); + bool overflow = false; /* Ensure that res = val1 [+*] val2 >= val1 or that res = val1 - val2 <= val1. */ - if (((code == PLUS_EXPR || code == MULT_EXPR) + if ((code == PLUS_EXPR && !(checkz == 1 || checkz == 0)) || (code == MINUS_EXPR && !(checkz == 0 || checkz == -1))) { + overflow = true; + } + /* Checking for multiplication overflow is done by dividing the + output of the multiplication by the first input of the + multiplication. If the result of that division operation is + not equal to the second input of the multiplication, then the + multiplication overflowed. */ + else if (code == MULT_EXPR && !integer_zerop (val1)) + { + tree tmp = int_const_binop (TRUNC_DIV_EXPR, + TYPE_MAX_VALUE (TREE_TYPE (val1)), + val1, 0); + int check = compare_values (tmp, val2); + + if (check != 0) + overflow = true; + } + + if (overflow) + { res = copy_node (res); TREE_OVERFLOW (res) = 1; } + } else if (TREE_OVERFLOW (res) && !TREE_OVERFLOW (val1) |