re PR c++/84192 (ICE with statement expression)

	PR c++/84192
	* constexpr.c (cxx_eval_constant_expression) <case RETURN_EXPR>: Don't
	set *jump_target to anything if jump_target is NULL.

	* g++.dg/cpp1y/constexpr-84192.C: New test.

Co-Authored-By: Jakub Jelinek <jakub@redhat.com>

From-SVN: r257770

gcc/cp/ChangeLog

+2018-02-16  Marek Polacek  <polacek@redhat.com>
+	    Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/84192
+	* constexpr.c (cxx_eval_constant_expression) <case RETURN_EXPR>: Don't
+	set *jump_target to anything if jump_target is NULL.
+
 2018-02-16  Jason Merrill  <jason@redhat.com>
 
 	PR c++/84151 - unnecessary volatile load with static member.

gcc/cp/constexpr.c

@@ -4254,7 +4254,16 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
 	r = cxx_eval_constant_expression (ctx, TREE_OPERAND (t, 0),
 					  lval,
 					  non_constant_p, overflow_p);
-      *jump_target = t;
+      if (jump_target)
+	*jump_target = t;
+      else
+	{
+	  /* Can happen with ({ return true; }) && false; passed to
+	     maybe_constant_value.  There is nothing to jump over in this
+	     case, and the bug will be diagnosed later.  */
+	  gcc_assert (ctx->quiet);
+	  *non_constant_p = true;
+	}
       break;
 
     case SAVE_EXPR:

gcc/testsuite/ChangeLog

+2018-02-16  Marek Polacek  <polacek@redhat.com>
+	    Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/84192
+	* g++.dg/cpp1y/constexpr-84192.C: New test.
+
 2018-02-16  Martin Sebor  <msebor@redhat.com>
 
 	PR c++/79064

gcc/testsuite/g++.dg/cpp1y/constexpr-84192.C

+// PR c++/84192
+// { dg-do compile { target c++14 } }
+// { dg-options "" }
+
+bool
+f1 ()
+{ 
+  return ({ return true; }) && false;	// { dg-error "could not convert" }
+}
+
+void
+f2 ()
+{ 
+  for (;;)
+    constexpr bool b = ({ break; false; }) && false;	// { dg-error "statement is not a constant expression" }
+}
+
+constexpr bool
+f3 (int n)
+{
+  bool b = false;
+  for (int i = 0; i < n; i++)
+    b = ({ break; });	// { dg-error "void value not ignored as it ought to be" }
+  return b;
+}
+
+constexpr bool b = f3 (4);
+
+bool
+f4 ()
+{
+  constexpr bool b = ({ return true; }) && false;	// { dg-error "could not convert" }
+  return false;
+}
+
+constexpr bool
+f5 (int x)
+{
+  constexpr bool b = ({ switch (x) case 0: true; }) && false;	// { dg-error "could not convert" }
+  return false;
+}