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authorMarek Polacek <polacek@redhat.com>2015-07-30 08:31:59 +0000
committerMarek Polacek <mpolacek@gcc.gnu.org>2015-07-30 08:31:59 +0000
commit173864e8f143d138c2805c03699d8d58b2c970c8 (patch)
tree6d585d350099dc5419318d05edf0701334efd02c /gcc/c-family
parent53a19317f40159b3fd96391a87182c8e0c7072c4 (diff)
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c-common.c (warn_tautological_cmp): Bail for float types.
* c-common.c (warn_tautological_cmp): Bail for float types. * c-c++-common/Wtautological-compare-3.c: New test. From-SVN: r226388
Diffstat (limited to 'gcc/c-family')
-rw-r--r--gcc/c-family/ChangeLog4
-rw-r--r--gcc/c-family/c-common.c6
2 files changed, 10 insertions, 0 deletions
diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index 06853ea..d895394 100644
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,7 @@
+2015-07-30 Marek Polacek <polacek@redhat.com>
+
+ * c-common.c (warn_tautological_cmp): Bail for float types.
+
2015-07-27 Marek Polacek <polacek@redhat.com>
PR bootstrap/67030
diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index caa801e..a8e5353 100644
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -1910,6 +1910,12 @@ warn_tautological_cmp (location_t loc, enum tree_code code, tree lhs, tree rhs)
|| (CONVERT_EXPR_P (rhs) || TREE_CODE (rhs) == NON_LVALUE_EXPR))
return;
+ /* Don't warn if either LHS or RHS has an IEEE floating-point type.
+ It could be a NaN, and NaN never compares equal to anything, even
+ itself. */
+ if (FLOAT_TYPE_P (TREE_TYPE (lhs)) || FLOAT_TYPE_P (TREE_TYPE (rhs)))
+ return;
+
if (operand_equal_p (lhs, rhs, 0))
{
/* Don't warn about array references with constant indices;