diff options
| author | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-02-24 19:55:47 +0000 |
|---|---|---|
| committer | rguenth <rguenth@138bc75d-0d04-0410-961f-82ee72b054a4> | 2007-02-24 19:55:47 +0000 |
| commit | 428b02b455d432f94f3c804dddb49392b2de3011 (patch) | |
| tree | 519e3bd036acaa7e2d9abb7b298d90d27eb168d5 /gcc | |
| parent | 40f89ebf453edf50b8dd69e7df4d8ca71eefff35 (diff) | |
| download | gcc-428b02b455d432f94f3c804dddb49392b2de3011.tar.gz | |
2007-02-24 Richard Guenther <rguenther@suse.de>
PR middle-end/30951
* fold-const.c (fold_binary): Fold x +- CST op x for
EQ_EXPR and NE_EXPR.
* gcc.dg/pr30951.c: New testcase.
git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@122295 138bc75d-0d04-0410-961f-82ee72b054a4
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 6 | ||||
| -rw-r--r-- | gcc/fold-const.c | 18 | ||||
| -rw-r--r-- | gcc/testsuite/ChangeLog | 5 | ||||
| -rw-r--r-- | gcc/testsuite/gcc.dg/pr30951.c | 36 |
4 files changed, 65 insertions, 0 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index 58980dcd200..2368d6a0155 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,9 @@ +2007-02-24 Richard Guenther <rguenther@suse.de> + + PR middle-end/30951 + * fold-const.c (fold_binary): Fold x +- CST op x for + EQ_EXPR and NE_EXPR. + 2007-02-24 John David Anglin <dave.anglin@nrc-cnrc.gc.ca> * pa.md (muldi3): Force subregs to registers in 64-bit expander. diff --git a/gcc/fold-const.c b/gcc/fold-const.c index ffd63cf5e7e..80c3c41ecff 100644 --- a/gcc/fold-const.c +++ b/gcc/fold-const.c @@ -11203,6 +11203,24 @@ fold_binary (enum tree_code code, tree type, tree op0, tree op1) fold_convert (TREE_TYPE (arg0), arg1), TREE_OPERAND (arg0, 1))); + /* Transform comparisons of the form X +- C CMP X. */ + if ((TREE_CODE (arg0) == PLUS_EXPR || TREE_CODE (arg0) == MINUS_EXPR) + && operand_equal_p (TREE_OPERAND (arg0, 0), arg1, 0) + && TREE_CODE (TREE_OPERAND (arg0, 1)) == INTEGER_CST + && (INTEGRAL_TYPE_P (TREE_TYPE (arg0)) + || POINTER_TYPE_P (TREE_TYPE (arg0)))) + { + tree cst = TREE_OPERAND (arg0, 1); + + if (code == EQ_EXPR + && !integer_zerop (cst)) + return omit_two_operands (type, boolean_false_node, + TREE_OPERAND (arg0, 0), arg1); + else + return omit_two_operands (type, boolean_true_node, + TREE_OPERAND (arg0, 0), arg1); + } + /* If we have X - Y == 0, we can convert that to X == Y and similarly for !=. Don't do this for ordered comparisons due to overflow. */ if (TREE_CODE (arg0) == MINUS_EXPR diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog index a4b1af91207..bd67ab6de6b 100644 --- a/gcc/testsuite/ChangeLog +++ b/gcc/testsuite/ChangeLog @@ -1,3 +1,8 @@ +2007-02-24 Richard Guenther <rguenther@suse.de> + + PR middle-end/30951 + * gcc.dg/pr30951.c: New testcase. + 2007-02-24 Kaveh R. Ghazi <ghazi@caip.rutgers.edu> * gcc.dg/torture/builtin-modf-1.c: New test. diff --git a/gcc/testsuite/gcc.dg/pr30951.c b/gcc/testsuite/gcc.dg/pr30951.c new file mode 100644 index 00000000000..149b8ecaafd --- /dev/null +++ b/gcc/testsuite/gcc.dg/pr30951.c @@ -0,0 +1,36 @@ +/* { dg-do link } */ + +extern void link_error (void); + +void test (int x, unsigned int y) +{ + if (x + 5 == x) + link_error (); + if (x == x + 10) + link_error (); + if (y + 5 == y) + link_error (); + if (y == y + 10) + link_error (); + if (x + 5 != x) + ; + else + link_error (); + if (x != x + 10) + ; + else + link_error (); + if (y + 5 != y) + ; + else + link_error (); + if (y != y + 10) + ; + else + link_error (); +} + +int main() +{ + return 0; +} |