From: Jason Merrill <jason@redhat.com>
Date: Mon, 19 Jun 2017 20:55:21 +0000 (-0400)
Subject: PR c++/80829 - ICE with constexpr copy of base subobject.
X-Git-Tag: basepoints/gcc-9~6503
X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=ecc5761533690734622d57cbe25914c44d7913e1;p=thirdparty%2Fgcc.git

PR c++/80829 - ICE with constexpr copy of base subobject.

	* constexpr.c (clear_no_implicit_zero): New.
	(cxx_eval_call_expression): Call it.

From-SVN: r249386
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index b80d3738319c..ff4280aebd10 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2017-06-19  Jason Merrill  <jason@redhat.com>
+
+	PR c++/80829 - ICE with constexpr copy of base subobject.
+	* constexpr.c (clear_no_implicit_zero): New.
+	(cxx_eval_call_expression): Call it.
+
 2017-06-19  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/81124
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 569a247d6b0a..5a5745248664 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -1394,6 +1394,21 @@ cxx_eval_internal_function (const constexpr_ctx *ctx, tree t,
   return t;
 }
 
+/* Clean CONSTRUCTOR_NO_IMPLICIT_ZERO from CTOR and its sub-aggregates.  */
+
+static void
+clear_no_implicit_zero (tree ctor)
+{
+  if (CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor))
+    {
+      CONSTRUCTOR_NO_IMPLICIT_ZERO (ctor) = false;
+      tree elt; unsigned HOST_WIDE_INT idx;
+      FOR_EACH_CONSTRUCTOR_VALUE (CONSTRUCTOR_ELTS (ctor), idx, elt)
+	if (TREE_CODE (elt) == CONSTRUCTOR)
+	  clear_no_implicit_zero (elt);
+    }
+}
+
 /* Subroutine of cxx_eval_constant_expression.
    Evaluate the call expression tree T in the context of OLD_CALL expression
    evaluation.  */
@@ -1697,7 +1712,7 @@ cxx_eval_call_expression (const constexpr_ctx *ctx, tree t,
 
   /* The result of a constexpr function must be completely initialized.  */
   if (TREE_CODE (result) == CONSTRUCTOR)
-    CONSTRUCTOR_NO_IMPLICIT_ZERO (result) = false;
+    clear_no_implicit_zero (result);
 
   pop_cx_call_context ();
   return unshare_constructor (result);
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-base5.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-base5.C
new file mode 100644
index 000000000000..84700bccff76
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-base5.C
@@ -0,0 +1,15 @@
+// PR c++/80829
+// { dg-do compile { target c++11 } }
+
+struct A {
+  constexpr A(int a) : _a(a) {}
+  int _a;
+};
+
+struct B : public A {
+  constexpr B(int a) : A(a) {}
+};
+
+int main() {
+  constexpr A a = B(10);
+}