c-family:
2016-10-17  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* c-common.c (c_common_truthvalue_conversion): Warn only for signed
	integer shift ops in boolean context.

testsuite:
2016-10-17  Bernd Edlinger  <bernd.edlinger@hotmail.de>

	* c-c++-common/Wint-in-bool-context-2.c: New test.

Index: gcc/c-family/c-common.c
===================================================================
--- gcc/c-family/c-common.c	(revision 241270)
+++ gcc/c-family/c-common.c	(working copy)
@@ -3328,8 +3328,10 @@
 					       TREE_OPERAND (expr, 0));
 
     case LSHIFT_EXPR:
-      warning_at (EXPR_LOCATION (expr), OPT_Wint_in_bool_context,
-		  "<< in boolean context, did you mean '<' ?");
+      if (TREE_CODE (TREE_TYPE (expr)) == INTEGER_TYPE
+	  && !TYPE_UNSIGNED (TREE_TYPE (expr)))
+	warning_at (EXPR_LOCATION (expr), OPT_Wint_in_bool_context,
+		    "<< in boolean context, did you mean '<' ?");
       break;
 
     case COND_EXPR:
Index: gcc/testsuite/c-c++-common/Wint-in-bool-context-2.c
===================================================================
--- gcc/testsuite/c-c++-common/Wint-in-bool-context-2.c	(revision 0)
+++ gcc/testsuite/c-c++-common/Wint-in-bool-context-2.c	(working copy)
@@ -0,0 +1,17 @@
+/* { dg-options "-Wint-in-bool-context" } */
+/* { dg-do compile } */
+
+typedef unsigned u32;
+typedef unsigned char u8;
+#define KEYLENGTH 8
+
+int foo (u8 plen, u32 key)
+{
+  if ((plen < KEYLENGTH) && (key << plen)) /* { dg-bogus "boolean context" } */
+    return -1;
+
+  if ((plen << KEYLENGTH) && (key < plen)) /* { dg-warning "boolean context" } */
+    return -2;
+
+  return 0;
+}