C++ PATCH to fix ICE with -Wbool-operation (PR c++/82040)

[Marek Polacek]

Here we got into re-entering the error reporting routines because the
warning_at call wasn't guarded with "complain", and crash ensued.

Bootstrapped/regtested on x86_64-linux, ok for trunk/7?

2017-08-31  Marek Polacek  <pola...@redhat.com>

        PR c++/82040
        * typeck.c (cp_build_unary_op): Avoid re-entering reporting routines.

        * g++.dg/warn/Wbool-operation-1.C: New test.

diff --git gcc/cp/typeck.c gcc/cp/typeck.c
index 171c2dfb57c..b303ceaede1 100644
--- gcc/cp/typeck.c
+++ gcc/cp/typeck.c
@@ -5982,6 +5982,7 @@ cp_build_unary_op (enum tree_code code, tree xarg, bool 
noconvert,
        {
          /* Warn if the expression has boolean value.  */
          if (TREE_CODE (TREE_TYPE (arg)) == BOOLEAN_TYPE
+             && (complain & tf_error)
              && warning_at (location, OPT_Wbool_operation,
                             "%<~%> on an expression of type bool"))
            inform (location, "did you mean to use logical not (%<!%>)?");
diff --git gcc/testsuite/g++.dg/warn/Wbool-operation-1.C 
gcc/testsuite/g++.dg/warn/Wbool-operation-1.C
index e69de29bb2d..4512b858287 100644
--- gcc/testsuite/g++.dg/warn/Wbool-operation-1.C
+++ gcc/testsuite/g++.dg/warn/Wbool-operation-1.C
@@ -0,0 +1,11 @@
+// PR c++/82040
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wbool-operation" }
+
+template <class c>
+decltype (~c{})
+call ()
+{
+  return ~false; // { dg-warning "on an expression of type bool" }
+}
+template int call<bool>();

        Marek