From b46e1a69975d64ad436ff1c928e008105b2b2a8d Mon Sep 17 00:00:00 2001
From: Marek Polacek <polacek@redhat.com>
Date: Thu, 13 Dec 2018 20:47:32 +0000
Subject: [PATCH] PR c++/88216 - ICE with class type in non-type template
 parameter.

	* mangle.c (write_expression): Handle TARGET_EXPR and
	VIEW_CONVERT_EXPR.
	* pt.c (convert_nontype_argument): Don't call
	get_template_parm_object for value-dependent expressions.

	* g++.dg/cpp2a/nontype-class9.C: New test.

From-SVN: r267108
---
 gcc/cp/ChangeLog                            |  8 ++++++
 gcc/cp/mangle.c                             | 10 ++++++-
 gcc/cp/pt.c                                 |  3 ++-
 gcc/testsuite/ChangeLog                     |  5 ++++
 gcc/testsuite/g++.dg/cpp2a/nontype-class9.C | 29 +++++++++++++++++++++
 5 files changed, 53 insertions(+), 2 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp2a/nontype-class9.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 503bbbb7598..46557bec5c2 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,11 @@
+2018-12-13  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/88216 - ICE with class type in non-type template parameter.
+	* mangle.c (write_expression): Handle TARGET_EXPR and
+	VIEW_CONVERT_EXPR.
+	* pt.c (convert_nontype_argument): Don't call
+	get_template_parm_object for value-dependent expressions.
+
 2018-12-13  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/87531
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index 64415894bc5..56247883010 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -2836,13 +2836,21 @@ write_expression (tree expr)
 {
   enum tree_code code = TREE_CODE (expr);
 
+  if (TREE_CODE (expr) == TARGET_EXPR)
+    {
+      expr = TARGET_EXPR_INITIAL (expr);
+      code = TREE_CODE (expr);
+    }
+
   /* Skip NOP_EXPR and CONVERT_EXPR.  They can occur when (say) a pointer
      argument is converted (via qualification conversions) to another type.  */
   while (CONVERT_EXPR_CODE_P (code)
 	 || location_wrapper_p (expr)
 	 /* Parentheses aren't mangled.  */
 	 || code == PAREN_EXPR
-	 || code == NON_LVALUE_EXPR)
+	 || code == NON_LVALUE_EXPR
+	 || (code == VIEW_CONVERT_EXPR
+	     && TREE_CODE (TREE_OPERAND (expr, 0)) == TEMPLATE_PARM_INDEX))
     {
       expr = TREE_OPERAND (expr, 0);
       code = TREE_CODE (expr);
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 8560e588593..3b378ee9ff4 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -7123,7 +7123,8 @@ convert_nontype_argument (tree type, tree expr, tsubst_flags_t complain)
     {
       /* Replace the argument with a reference to the corresponding template
 	 parameter object.  */
-      expr = get_template_parm_object (expr, complain);
+      if (!value_dependent_expression_p (expr))
+	expr = get_template_parm_object (expr, complain);
       if (expr == error_mark_node)
 	return NULL_TREE;
     }
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 19c82c17b46..a3076872723 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2018-12-13  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/88216 - ICE with class type in non-type template parameter.
+	* g++.dg/cpp2a/nontype-class9.C: New test.
+
 2018-12-13  Jakub Jelinek  <jakub@redhat.com>
 
 	PR rtl-optimization/88416
diff --git a/gcc/testsuite/g++.dg/cpp2a/nontype-class9.C b/gcc/testsuite/g++.dg/cpp2a/nontype-class9.C
new file mode 100644
index 00000000000..737f712be47
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/nontype-class9.C
@@ -0,0 +1,29 @@
+// PR c++/88216
+// { dg-do compile { target c++2a } }
+
+template <class T, class U> struct same;
+template <class T> struct same<T,T> {};
+
+struct T { };
+
+template <T t>
+struct U { };
+
+template <T t>
+void f (U<t>)
+{
+  same<T,decltype(t)> s;
+  same<const T&,decltype((t))> s2;
+}
+
+template<T t>
+U<t> u;
+
+T t;
+U<t> u2;
+
+void
+g ()
+{
+  f<t>(u2);
+}
-- 
2.30.2