From 2db613e5d3a2698fcd32460ad23b0c1b8ae31c7a Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Tue, 4 Oct 2016 17:14:18 -0400
Subject: [PATCH] PR c++/77775 - misoptimization of PMF comparison

	* constexpr.c (cxx_eval_component_reference): Use name matching
	for PMFs.

From-SVN: r240757
---
 gcc/cp/ChangeLog                            |  6 ++++++
 gcc/cp/constexpr.c                          |  8 +++++++-
 gcc/testsuite/g++.dg/cpp0x/constexpr-pmf1.C | 17 +++++++++++++++++
 3 files changed, 30 insertions(+), 1 deletion(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp0x/constexpr-pmf1.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3fc378ae463..b7a57e072da 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2016-09-30  Jason Merrill  <jason@redhat.com>
+
+	PR c++/77775
+	* constexpr.c (cxx_eval_component_reference): Use name matching
+	for PMFs.
+
 2016-10-04  Jason Merrill  <jason@redhat.com>
 
 	Implement P0091R2, Template argument deduction for class templates.
diff --git a/gcc/cp/constexpr.c b/gcc/cp/constexpr.c
index 2db13d2e187..4acbb2600b4 100644
--- a/gcc/cp/constexpr.c
+++ b/gcc/cp/constexpr.c
@@ -2315,9 +2315,13 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t,
     }
   if (*non_constant_p)
     return t;
+  bool pmf = TYPE_PTRMEMFUNC_P (TREE_TYPE (whole));
   FOR_EACH_CONSTRUCTOR_ELT (CONSTRUCTOR_ELTS (whole), i, field, value)
     {
-      if (field == part)
+      /* Use name match for PMF fields, as a variant will have a
+	 different FIELD_DECL with a different type.  */
+      if (pmf ? DECL_NAME (field) == DECL_NAME (part)
+	  : field == part)
 	{
 	  if (value)
 	    return value;
@@ -2342,6 +2346,8 @@ cxx_eval_component_reference (const constexpr_ctx *ctx, tree t,
   if (is_really_empty_class (TREE_TYPE (t)))
     return build_constructor (TREE_TYPE (t), NULL);
 
+  gcc_assert (DECL_CONTEXT (part) == TYPE_MAIN_VARIANT (TREE_TYPE (whole)));
+
   if (CONSTRUCTOR_NO_IMPLICIT_ZERO (whole))
     {
       /* 'whole' is part of the aggregate initializer we're currently
diff --git a/gcc/testsuite/g++.dg/cpp0x/constexpr-pmf1.C b/gcc/testsuite/g++.dg/cpp0x/constexpr-pmf1.C
new file mode 100644
index 00000000000..b6a7935746f
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/constexpr-pmf1.C
@@ -0,0 +1,17 @@
+// PR c++/77775
+// { dg-options -fdump-tree-gimple }
+// { dg-final { scan-tree-dump "== viewAdded" "gimple" { target c++11 } } }
+
+namespace Sublime {
+struct View;
+struct AreaIndex;
+struct Area {
+  void qt_static_metacall();
+  void viewAdded(AreaIndex *, View *);
+};
+}
+void Sublime::Area::qt_static_metacall() {
+  typedef void (Area::*_t)(AreaIndex *, View *);
+  if (*reinterpret_cast<_t *>(1) == _t(&Area::viewAdded))
+    __builtin_abort();
+}
-- 
2.30.2