From: Jakub Jelinek <jakub@redhat.com>
Date: Fri, 20 Dec 2019 17:32:23 +0000 (+0100)
Subject: backport: re PR c++/92695 (P1064R0 - virtual constexpr fails if object taken from... 
X-Git-Tag: releases/gcc-9.3.0~290
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d9c7be4ce3b0590ee1c143e29635c084e2704c62;p=thirdparty%2Fgcc.git

backport: re PR c++/92695 (P1064R0 - virtual constexpr fails if object taken from array)

	Backported from mainline
	2019-12-02  Jakub Jelinek  <jakub@redhat.com>

	PR c++/92695
	* constexpr.c (cxx_eval_constant_expression) <case OBJ_TYPE_REF>: Use
	STRIP_NOPS before checking for ADDR_EXPR.

	* g++.dg/cpp2a/constexpr-virtual15.C: New test.

From-SVN: r279663
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index af8983803107..2e47b485d546 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,6 +1,12 @@
 2019-12-20  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2019-12-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92695
+	* constexpr.c (cxx_eval_constant_expression) <case OBJ_TYPE_REF>: Use
+	STRIP_NOPS before checking for ADDR_EXPR.
+
 	2019-11-29  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/60228
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 9845416a8121..13d8a17c3e04 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -5124,6 +5124,7 @@ cxx_eval_constant_expression (const constexpr_ctx *ctx, tree t,
 	tree obj = OBJ_TYPE_REF_OBJECT (t);
 	obj = cxx_eval_constant_expression (ctx, obj, lval, non_constant_p,
 					    overflow_p);
+	STRIP_NOPS (obj);
 	/* We expect something in the form of &x.D.2103.D.2094; get x. */
 	if (TREE_CODE (obj) != ADDR_EXPR
 	    || !DECL_P (get_base_address (TREE_OPERAND (obj, 0))))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 917de8fb18ac..d50e9836b839 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,6 +1,11 @@
 2019-12-20  Jakub Jelinek  <jakub@redhat.com>
 
 	Backported from mainline
+	2019-12-02  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92695
+	* g++.dg/cpp2a/constexpr-virtual15.C: New test.
+
 	2019-11-29  Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/60228
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-virtual15.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-virtual15.C
new file mode 100644
index 000000000000..cb55aa3bb560
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-virtual15.C
@@ -0,0 +1,7 @@
+// PR c++/92695
+// { dg-do compile { target c++2a } }
+
+struct A { virtual int get() = 0; };
+struct B : A { constexpr int get() override { return 10; } };
+struct D { B b[2]; A* c{&(b[0])}; };
+static_assert(D{}.c->get() == 10);