The -Wlogical-not-parentheses deliberately doesn't warn when the RHS has
boolean type. But since in C the type of a comparison is int, we need
to check for tcc_comparison, too.
Bootstrapped/regtested on x86_64-linux and ppc64le-redhat-linux, ok for trunk?
2016-08-24 Marek Polacek <pola...@redhat.com>
PR c/77292
* c-common.c (warn_logical_not_parentheses): Don't warn if RHS is
a comparison.
* c-c++-common/Wlogical-not-parentheses-1.c: New test.
diff --git gcc/c-family/c-common.c gcc/c-family/c-common.c
index 3feb910..47255c3 100644
--- gcc/c-family/c-common.c
+++ gcc/c-family/c-common.c
@@ -1481,7 +1481,7 @@ warn_tautological_cmp (location_t loc, enum tree_code
code, tree lhs, tree rhs)
/* Warn about logical not used on the left hand side operand of a comparison.
This function assumes that the LHS is inside of TRUTH_NOT_EXPR.
- Do not warn if RHS is of a boolean type. */
+ Do not warn if RHS is of a boolean type, or a comparison. */
void
warn_logical_not_parentheses (location_t location, enum tree_code code,
@@ -1489,7 +1489,8 @@ warn_logical_not_parentheses (location_t location, enum
tree_code code,
{
if (TREE_CODE_CLASS (code) != tcc_comparison
|| TREE_TYPE (rhs) == NULL_TREE
- || TREE_CODE (TREE_TYPE (rhs)) == BOOLEAN_TYPE)
+ || TREE_CODE (TREE_TYPE (rhs)) == BOOLEAN_TYPE
+ || TREE_CODE_CLASS (TREE_CODE (rhs)) == tcc_comparison)
return;
/* Don't warn for !x == 0 or !y != 0, those are equivalent to
diff --git gcc/testsuite/c-c++-common/Wlogical-not-parentheses-1.c
gcc/testsuite/c-c++-common/Wlogical-not-parentheses-1.c
index e69de29..4ae9ec2 100644
--- gcc/testsuite/c-c++-common/Wlogical-not-parentheses-1.c
+++ gcc/testsuite/c-c++-common/Wlogical-not-parentheses-1.c
@@ -0,0 +1,18 @@
+/* PR c/77292 */
+/* { dg-do compile } */
+/* { dg-options "-Wlogical-not-parentheses" } */
+
+ /* Test that we don't warn if rhs is a comparison. */
+
+int
+foo (int a, int b)
+{
+ int r = 0;
+ r += !a == (a < b);
+ r += !a == (a > b);
+ r += !a == (a >= b);
+ r += !a == (a <= b);
+ r += !a == (a != b);
+ r += !a == (a == b);
+ return r;
+}
Marek
