constexpr.c (cxx_eval_constant_expression): If not skipping upon entry to body...

	* constexpr.c (cxx_eval_constant_expression) <case CLEANUP_STMT>: If
	not skipping upon entry to body, run cleanup with the same *jump_target
	as it started to run the cleanup even if the body returns, breaks or
	continues.
	(potential_constant_expression_1): Allow CLEANUP_STMT.

	* g++.dg/ext/constexpr-attr-cleanup1.C: New test.

From-SVN: r276494

gcc/cp/ChangeLog

 2019-10-03  Jakub Jelinek  <jakub@redhat.com>
 
+	* constexpr.c (cxx_eval_constant_expression) <case CLEANUP_STMT>: If
+	not skipping upon entry to body, run cleanup with the same *jump_target
+	as it started to run the cleanup even if the body returns, breaks or
+	continues.
+	(potential_constant_expression_1): Allow CLEANUP_STMT.
+
 	* constexpr.c (cxx_eval_store_expression): Formatting fix.  Handle
 	const_object_being_modified with array type.
 

gcc/cp/constexpr.c

@@ -4899,14 +4899,21 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
       break;
 
     case CLEANUP_STMT:
-      r = cxx_eval_constant_expression (ctx, CLEANUP_BODY (t), lval,
+      {
+	tree initial_jump_target = jump_target ? *jump_target : NULL_TREE;
+	r = cxx_eval_constant_expression (ctx, CLEANUP_BODY (t), lval,
+					  non_constant_p, overflow_p,
+					  jump_target);
+	if (!CLEANUP_EH_ONLY (t) && !*non_constant_p)
+	  /* Also evaluate the cleanup.  If we weren't skipping at the
+	     start of the CLEANUP_BODY, change jump_target temporarily
+	     to &initial_jump_target, so that even a return or break or
+	     continue in the body doesn't skip the cleanup.  */
+	  cxx_eval_constant_expression (ctx, CLEANUP_EXPR (t), true,
 					non_constant_p, overflow_p,
-					jump_target);
-      if (!CLEANUP_EH_ONLY (t) && !*non_constant_p)
-	/* Also evaluate the cleanup.  */
-	cxx_eval_constant_expression (ctx, CLEANUP_EXPR (t), true,
-				      non_constant_p, overflow_p,
-				      jump_target);
+					jump_target ? &initial_jump_target
+					: NULL);
+      }
       break;
 
       /* These differ from cxx_eval_unary_expression in that this doesn't
@@ -6975,6 +6982,12 @@ potential_constant_expression_1 (tree t, bool want_rval, bool strict, bool now,
       return true;
 
     case CLEANUP_STMT:
+      if (!RECUR (CLEANUP_BODY (t), any))
+	return false;
+      if (!CLEANUP_EH_ONLY (t) && !RECUR (CLEANUP_EXPR (t), any))
+	return false;
+      return true;
+
     case EMPTY_CLASS_EXPR:
     case PREDICT_EXPR:
       return false;

gcc/testsuite/ChangeLog

+2019-10-03  Jakub Jelinek  <jakub@redhat.com>
+
+	* g++.dg/ext/constexpr-attr-cleanup1.C: New test.
+
 2019-10-02  Martin Sebor  <msebor@redhat.com>
 
 	PR tree-optimization/80936

gcc/testsuite/g++.dg/ext/constexpr-attr-cleanup1.C

+// { dg-do compile { target c++2a } }
+
+constexpr void
+cleanup (int *x)
+{
+  if (x)
+    asm ("");		// { dg-error "inline assembly is not a constant expression" }
+}			// { dg-message "only unevaluated inline assembly is allowed in a 'constexpr' function" "" { target *-*-* } .-1 }
+
+constexpr void
+cleanup2 (int *x)
+{
+}
+
+constexpr bool
+foo ()
+{
+  int a __attribute__((cleanup (cleanup))) = 1;
+  return true;
+}
+
+constexpr bool
+bar ()
+{
+  int a __attribute__((cleanup (cleanup2))) = 1;
+  return true;
+}
+
+constexpr auto x = foo ();	// { dg-message "in 'constexpr' expansion of" }
+constexpr auto y = bar ();