c-common.c (maybe_warn_bool_compare): When comparing with 0/1, require that the non...

	* c-common.c (maybe_warn_bool_compare): When comparing with 0/1,
	require that the non-constant be of a boolean type.

	* c-c++-common/Wbool-compare-3.c: New test.

From-SVN: r222622

diff --git a/gcc/c-family/ChangeLog b/gcc/c-family/ChangeLog
index c17ea5f6138f814ceeaf95975ce76809efd3961c..8c2e93345ac2e414ebba0307c5d3afe2caeeaef0 100644 (file)
--- a/gcc/c-family/ChangeLog
+++ b/gcc/c-family/ChangeLog
@@ -1,3 +1,8 @@
+2015-04-30  Marek Polacek  <polacek@redhat.com>
+
+       * c-common.c (maybe_warn_bool_compare): When comparing with 0/1,
+       require that the non-constant be of a boolean type.
+
 2015-04-29  Josh Triplett  <josh@joshtriplett.org>
 
         * c-common.c (handle_section_attribute): Refactor to reduce

diff --git a/gcc/c-family/c-common.c b/gcc/c-family/c-common.c
index 7d314f854fe231784c3d0070a0fc73e611af3a2c..ada8e8aa9016d0e93448f6befe97ef2560e3f016 100644 (file)
--- a/gcc/c-family/c-common.c
+++ b/gcc/c-family/c-common.c
@@ -11924,6 +11924,17 @@ maybe_warn_bool_compare (location_t loc, enum tree_code code, tree op0,
     }
   else if (integer_zerop (cst) || integer_onep (cst))
     {
+      /* If the non-constant operand isn't of a boolean type, we
+        don't want to warn here.  */
+      tree noncst = TREE_CODE (op0) == INTEGER_CST ? op1 : op0;
+      /* Handle booleans promoted to integers.  */
+      if (CONVERT_EXPR_P (noncst)
+         && TREE_TYPE (noncst) == integer_type_node
+         && TREE_CODE (TREE_TYPE (TREE_OPERAND (noncst, 0))) == BOOLEAN_TYPE)
+       /* Warn.  */;
+      else if (TREE_CODE (TREE_TYPE (noncst)) != BOOLEAN_TYPE
+              && !truth_value_p (TREE_CODE (noncst)))
+       return;
       /* Do some magic to get the right diagnostics.  */
       bool flag = TREE_CODE (op0) == INTEGER_CST;
       flag = integer_zerop (cst) ? flag : !flag;

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index e0df670404ca7f694f79f4bb4435631b39f8c1e0..455776844e370d09063c01161d7db72dc7d64f31 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,7 @@
+2015-04-30  Marek Polacek  <polacek@redhat.com>
+
+       * c-c++-common/Wbool-compare-3.c: New test.
+
 2015-04-30  Paolo Carlini  <paolo.carlini@oracle.com>
 
        PR c++/57610

diff --git a/gcc/testsuite/c-c++-common/Wbool-compare-3.c b/gcc/testsuite/c-c++-common/Wbool-compare-3.c
new file mode 100644 (file)
index 0000000..bac4f47
--- /dev/null
+++ b/gcc/testsuite/c-c++-common/Wbool-compare-3.c
@@ -0,0 +1,30 @@
+/* { dg-do compile } */
+/* { dg-options "-Wbool-compare" } */
+
+#ifndef __cplusplus
+# define bool _Bool
+#endif
+
+#define A 0
+#define B 1
+
+int
+foo (int i, bool b)
+{
+  int r = 0;
+
+  r += i <= (A || B);
+  r += i <= b;
+  r += i <= A;
+  r += i < (A || B);
+  r += i < b;
+  r += i < A;
+  r += i > (A || B);
+  r += i > b;
+  r += i > A;
+  r += i >= (A || B);
+  r += i >= b;
+  r += i >= A;
+
+  return r;
+}