(truthvalue_conversion): Optionally warn if an

unparenthesized assignment is used as a truth value.

From-SVN: r1853

diff --git a/gcc/c-common.c b/gcc/c-common.c
index 50aa60e90aeba831bde9a9427e6e27a38b69eabe..33804c41a8d8601040177487ec3732df099ab221 100644 (file)
--- a/gcc/c-common.c
+++ b/gcc/c-common.c
@@ -901,6 +901,11 @@ truthvalue_conversion (expr)
                              fold (build1 (NOP_EXPR,
                                            TREE_TYPE (TREE_OPERAND (expr, 0)),
                                            TREE_OPERAND (expr, 1))), 1);
+
+    case MODIFY_EXPR:
+      if (warn_parentheses && C_EXP_ORIGINAL_CODE (expr) == MODIFY_EXPR)
+       warning ("suggest parentheses around assignment used as truth value");
+      break;
     }
 
   return build_binary_op (NE_EXPR, expr, integer_zero_node, 1);