From bb64bef659dc5b11fe1f8ff1f7df65603c9d8876 Mon Sep 17 00:00:00 2001
From: Marek Polacek <polacek@redhat.com>
Date: Thu, 5 Sep 2019 15:37:52 +0000
Subject: [PATCH] PR c++/91644 - ICE with constinit in function template.

	* decl.c (start_decl): Call retrofit_lang_decl for constinit variables.
	* pt.c (tsubst_expr): Pass LOOKUP_CONSTINIT down to cp_finish_decl for
	constinit variables.

	* g++.dg/cpp2a/constinit13.C: New test.

From-SVN: r275421
---
 gcc/cp/ChangeLog                         |  7 +++++
 gcc/cp/decl.c                            |  9 ++++++-
 gcc/cp/pt.c                              | 12 +++++++--
 gcc/testsuite/ChangeLog                  |  5 ++++
 gcc/testsuite/g++.dg/cpp2a/constinit13.C | 33 ++++++++++++++++++++++++
 5 files changed, 63 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/g++.dg/cpp2a/constinit13.C

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 3162bed785e..31a04ef226a 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,10 @@
+2019-09-05  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/91644 - ICE with constinit in function template.
+	* decl.c (start_decl): Call retrofit_lang_decl for constinit variables.
+	* pt.c (tsubst_expr): Pass LOOKUP_CONSTINIT down to cp_finish_decl for
+	constinit variables.
+
 2019-09-05  Nathan Sidwell  <nathan@acm.org>
 
 	* cp-tree.h (DECL_VTABLE_OR_VTT_P): Forward to DECL_VIRTUAL_P.
diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index 6de95cdfe79..825e1e61b5e 100644
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -5308,7 +5308,14 @@ start_decl (const cp_declarator *declarator,
     decl = maybe_push_decl (decl);
 
   if (processing_template_decl)
-    decl = push_template_decl (decl);
+    {
+      /* Make sure that for a `constinit' decl push_template_decl creates
+	 a DECL_TEMPLATE_INFO info for us, so that cp_finish_decl can then set
+	 TINFO_VAR_DECLARED_CONSTINIT.  */
+      if (decl_spec_seq_has_spec_p (declspecs, ds_constinit))
+	retrofit_lang_decl (decl);
+      decl = push_template_decl (decl);
+    }
   if (decl == error_mark_node)
     return error_mark_node;
 
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 15cc4b20a41..cec9798eef4 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -17108,6 +17108,13 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
 	else
 	  {
 	    init = DECL_INITIAL (decl);
+	    /* The following tsubst call will clear the DECL_TEMPLATE_INFO
+	       for local variables, so save if DECL was declared constinit.  */
+	    const bool constinit_p
+	      = (VAR_P (decl)
+		 && DECL_LANG_SPECIFIC (decl)
+		 && DECL_TEMPLATE_INFO (decl)
+		 && TINFO_VAR_DECLARED_CONSTINIT (DECL_TEMPLATE_INFO (decl)));
 	    decl = tsubst (decl, args, complain, in_decl);
 	    if (decl != error_mark_node)
 	      {
@@ -17146,7 +17153,7 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
 		  }
 		else
 		  {
-		    int const_init = false;
+		    bool const_init = false;
 		    unsigned int cnt = 0;
 		    tree first = NULL_TREE, ndecl = error_mark_node;
 		    maybe_push_decl (decl);
@@ -17167,7 +17174,8 @@ tsubst_expr (tree t, tree args, tsubst_flags_t complain, tree in_decl,
 		    if (ndecl != error_mark_node)
 		      cp_maybe_mangle_decomp (ndecl, first, cnt);
 
-		    cp_finish_decl (decl, init, const_init, NULL_TREE, 0);
+		    cp_finish_decl (decl, init, const_init, NULL_TREE,
+				    constinit_p ? LOOKUP_CONSTINIT : 0);
 
 		    if (ndecl != error_mark_node)
 		      cp_finish_decomp (ndecl, first, cnt);
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 3a905cb3156..9940cec8879 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2019-09-05  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/91644 - ICE with constinit in function template.
+	* g++.dg/cpp2a/constinit13.C: New test.
+
 2019-09-05  Jakub Jelinek  <jakub@redhat.com>
 
 	PR middle-end/91001
diff --git a/gcc/testsuite/g++.dg/cpp2a/constinit13.C b/gcc/testsuite/g++.dg/cpp2a/constinit13.C
new file mode 100644
index 00000000000..8ea64cc0e1e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp2a/constinit13.C
@@ -0,0 +1,33 @@
+// PR c++/91644 - ICE with constinit in function template.
+// { dg-do compile { target c++11 } }
+
+template <typename T>
+static void fn1 ()
+{
+  static __constinit auto v1 = 0;
+  static __constinit int v2 = 0;
+}
+
+int nonconst;
+
+template <typename T>
+static void fn2 ()
+{
+  static __constinit auto v1 = nonconst; // { dg-error "does not have a constant initializer|not usable" }
+  static __constinit int v2 = nonconst; // { dg-error "does not have a constant initializer|not usable" }
+}
+
+template <typename T>
+static void fn3 ()
+{
+  static __constinit T v1 = 0;
+  static __constinit T v2 = nonconst; // { dg-error "does not have a constant initializer|not usable" }
+}
+
+void
+g ()
+{
+  fn1<int>();
+  fn2<int>();
+  fn3<int>();
+}
-- 
2.30.2