math: use smatch_comparison.c for handling subtraction
authorDan Carpenter <dan.carpenter@oracle.com>
Wed, 23 Jan 2013 12:48:34 +0000 (15:48 +0300)
committerDan Carpenter <dan.carpenter@oracle.com>
Wed, 23 Jan 2013 12:48:34 +0000 (15:48 +0300)
commited0f45f296b18e956cd09cbb72995e42d16055c8
treed39318f72c1a0952077d3c03b4e97bcc6b654faa
parent2d002be825c42f986911a49b07ea134a1c8029a2
math: use smatch_comparison.c for handling subtraction

Basically the idea here is that if we know "a" is larger than "b" then
"a - b" is a number between "1 - a".

The implementation isn't totally right.  There are some issues with
signedness.  But I've been using it for a while and it doesn't seem to
cause many false positives.

Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
smatch_math.c