From: Nathan Sidwell <nathan@acm.org>
Date: Fri, 6 Mar 2020 18:51:26 +0000 (-0800)
Subject: Fix mangling ICE [PR94027]
X-Git-Tag: basepoints/gcc-11~1004
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=191bcd0f30dd37dec773efb0125afdcae9bd90ef;p=thirdparty%2Fgcc.git

Fix mangling ICE [PR94027]

	PR c++/94027
	* mangle.c (find_substitution): Don't call same_type_p on template
	args that cannot match.

Now same_type_p rejects argument packs, we need to be more careful
calling it with template argument vector contents.

The mangler needs to do some comparisons to find the special
substitutions.  While that code looks a little ugly, this seems the
smallest fix.
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index f01563e96fce..98640a671cc5 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-03-06  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/94027
+	* mangle.c (find_substitution): Don't call same_type_p on template
+	args that cannot match.
+
 2020-03-04  Martin Sebor  <msebor@redhat.com>
 
 	PR c++/90938
diff --git a/gcc/cp/mangle.c b/gcc/cp/mangle.c
index a0e888fde62f..1fc78bfa7536 100644
--- a/gcc/cp/mangle.c
+++ b/gcc/cp/mangle.c
@@ -628,6 +628,8 @@ find_substitution (tree node)
 	    {
 	      tree args = CLASSTYPE_TI_ARGS (type);
 	      if (TREE_VEC_LENGTH (args) == 3
+		  && (TREE_CODE (TREE_VEC_ELT (args, 0))
+		      == TREE_CODE (char_type_node))
 		  && same_type_p (TREE_VEC_ELT (args, 0), char_type_node)
 		  && is_std_substitution_char (TREE_VEC_ELT (args, 1),
 					       SUBID_CHAR_TRAITS)
@@ -652,7 +654,7 @@ find_substitution (tree node)
 	 args <char, std::char_traits<char> > .  */
       tree args = CLASSTYPE_TI_ARGS (type);
       if (TREE_VEC_LENGTH (args) == 2
-	  && TYPE_P (TREE_VEC_ELT (args, 0))
+	  && TREE_CODE (TREE_VEC_ELT (args, 0)) == TREE_CODE (char_type_node)
 	  && same_type_p (TREE_VEC_ELT (args, 0), char_type_node)
 	  && is_std_substitution_char (TREE_VEC_ELT (args, 1),
 				       SUBID_CHAR_TRAITS))
diff --git a/gcc/testsuite/g++.dg/pr94027.C b/gcc/testsuite/g++.dg/pr94027.C
new file mode 100644
index 000000000000..03cd68f1b0fc
--- /dev/null
+++ b/gcc/testsuite/g++.dg/pr94027.C
@@ -0,0 +1,22 @@
+// { dg-do compile { target c++11 } }
+// PR 94027 ICE mangling
+
+class a {
+public:
+  a (char);
+};
+struct b {
+  b (a);
+};
+template <typename... aw, int...>
+void ax (int)
+{
+  struct c : b {
+    c () : b {sizeof...(aw)}
+    {}
+  };
+}
+
+void az() {
+  ax ({});
+}