From e7dc5734a82ce4794027871556dfdd4bf1be2c25 Mon Sep 17 00:00:00 2001
From: Jason Merrill <jason@redhat.com>
Date: Sun, 27 Feb 2011 03:13:28 -0500
Subject: [PATCH] re PR c++/47904 (ICE with DECL_PARM_INDEX (this) in
 cp_tree_equal)

	PR c++/47904
	* tree.c (cp_tree_equal): Compare DECL_PARM_LEVEL.
	* pt.c (iterative_hash_template_arg): And hash it.

From-SVN: r170533
---
 gcc/cp/ChangeLog                           |  4 ++++
 gcc/cp/pt.c                                |  5 ++++-
 gcc/cp/tree.c                              | 19 ++++++++++++------
 gcc/testsuite/ChangeLog                    |  2 ++
 gcc/testsuite/g++.dg/template/this-targ1.C | 23 ++++++++++++++++++++++
 5 files changed, 46 insertions(+), 7 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/template/this-targ1.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 828336212b3..50e4b48d5ea 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2011-02-26  Jason Merrill  <jason@redhat.com>
 
+	PR c++/47904
+	* tree.c (cp_tree_equal): Compare DECL_PARM_LEVEL.
+	* pt.c (iterative_hash_template_arg): And hash it.
+
 	PR c++/47897
 	* semantics.c (non_const_var_error): Split out from...
 	(cxx_eval_constant_expression): ...here.
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index ed9d28b0b2f..4b262d00016 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -1533,7 +1533,10 @@ iterative_hash_template_arg (tree arg, hashval_t val)
 
     case PARM_DECL:
       if (!DECL_ARTIFICIAL (arg))
-	val = iterative_hash_object (DECL_PARM_INDEX (arg), val);
+	{
+	  val = iterative_hash_object (DECL_PARM_INDEX (arg), val);
+	  val = iterative_hash_object (DECL_PARM_LEVEL (arg), val);
+	}
       return iterative_hash_template_arg (TREE_TYPE (arg), val);
 
     case TARGET_EXPR:
diff --git a/gcc/cp/tree.c b/gcc/cp/tree.c
index d62d2427f1e..ed4f67bbb0f 100644
--- a/gcc/cp/tree.c
+++ b/gcc/cp/tree.c
@@ -2154,12 +2154,19 @@ cp_tree_equal (tree t1, tree t2)
 
     case PARM_DECL:
       /* For comparing uses of parameters in late-specified return types
-	 with an out-of-class definition of the function.  */
-      if (same_type_p (TREE_TYPE (t1), TREE_TYPE (t2))
-	  && DECL_PARM_INDEX (t1) == DECL_PARM_INDEX (t2))
-	return true;
-      else
-	return false;
+	 with an out-of-class definition of the function, but can also come
+	 up for expressions that involve 'this' in a member function
+	 template.  */
+      if (same_type_p (TREE_TYPE (t1), TREE_TYPE (t2)))
+	{
+	  if (DECL_ARTIFICIAL (t1) ^ DECL_ARTIFICIAL (t2))
+	    return false;
+	  if (DECL_ARTIFICIAL (t1)
+	      || (DECL_PARM_LEVEL (t1) == DECL_PARM_LEVEL (t2)
+		  && DECL_PARM_INDEX (t1) == DECL_PARM_INDEX (t2)))
+	    return true;
+	}
+      return false;
 
     case VAR_DECL:
     case CONST_DECL:
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index b23419a322c..8c5a37982c9 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,7 @@
 2011-02-26  Jason Merrill  <jason@redhat.com>
 
+	* g++.dg/template/this-targ1.C: New.
+
 	* g++.dg/cpp0x/regress/template-const1.C: New.
 	* g++.dg/cpp0x/regress/template-function1.C: Adjust.
 	* g++.dg/template/function1.C: Adjust.
diff --git a/gcc/testsuite/g++.dg/template/this-targ1.C b/gcc/testsuite/g++.dg/template/this-targ1.C
new file mode 100644
index 00000000000..6864be5abbc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/template/this-targ1.C
@@ -0,0 +1,23 @@
+// PR c++/47904
+
+template <bool>
+struct S
+{
+};
+
+template <class T>
+class U
+{
+  T t;
+  int foo () const
+  {
+    S <sizeof (t) == 1> s;
+    return 1;
+  }
+  int bar () const
+  {
+    S <sizeof (t) == 1> s;
+    return 1;
+  }
+};
+
-- 
2.30.2