PR c++/78373 - ICE with TREE_CONSTANT reference

	* decl.c (cp_finish_decl): Don't set TREE_CONSTANT on a reference.
	* typeck2.c (store_init_value): Likewise.

From-SVN: r242523

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index fdbd1536002a9db68fb04a06692762f9370829ec..088a63cab8454f41b84f02f23a78cdcb46c9dc8d 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,5 +1,9 @@
 2016-11-16  Jason Merrill  <jason@redhat.com>
 
+       PR c++/78373
+       * decl.c (cp_finish_decl): Don't set TREE_CONSTANT on a reference.
+       * typeck2.c (store_init_value): Likewise.
+
        * decl.c (store_decomp_type, lookup_decomp_type): New.
        (cp_finish_decomp): Call store_decomp_type.
        * semantics.c (finish_decltype_type): Call lookup_decomp_type.

diff --git a/gcc/cp/decl.c b/gcc/cp/decl.c
index c54a2de0af666f740c4864f49935a97ca885b0e9..2dc9314bc1e2e1d715edfda15ea4a8521bda5ac1 100644 (file)
--- a/gcc/cp/decl.c
+++ b/gcc/cp/decl.c
@@ -6839,7 +6839,9 @@ cp_finish_decl (tree decl, tree init, bool init_const_expr_p,
          /* Set these flags now for templates.  We'll update the flags in
             store_init_value for instantiations.  */
          DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl) = 1;
-         if (decl_maybe_constant_var_p (decl))
+         if (decl_maybe_constant_var_p (decl)
+             /* FIXME setting TREE_CONSTANT on refs breaks the back end.  */
+             && TREE_CODE (type) != REFERENCE_TYPE)
            TREE_CONSTANT (decl) = 1;
        }
     }

diff --git a/gcc/cp/typeck2.c b/gcc/cp/typeck2.c
index 022a47883a0e4def6eaeca21c901ce4fac3558f5..2ca4bf241ec285dffa1c6500975c39d180bfad96 100644 (file)
--- a/gcc/cp/typeck2.c
+++ b/gcc/cp/typeck2.c
@@ -824,7 +824,9 @@ store_init_value (tree decl, tree init, vec<tree, va_gc>** cleanups, int flags)
       const_init = (reduced_constant_expression_p (value)
                    || error_operand_p (value));
       DECL_INITIALIZED_BY_CONSTANT_EXPRESSION_P (decl) = const_init;
-      TREE_CONSTANT (decl) = const_init && decl_maybe_constant_var_p (decl);
+      /* FIXME setting TREE_CONSTANT on refs breaks the back end.  */
+      if (TREE_CODE (type) != REFERENCE_TYPE)
+       TREE_CONSTANT (decl) = const_init && decl_maybe_constant_var_p (decl);
     }
   value = cp_fully_fold (value);
 

diff --git a/gcc/testsuite/g++.dg/opt/pr78373.C b/gcc/testsuite/g++.dg/opt/pr78373.C
new file mode 100644 (file)
index 0000000..9ceef1c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/opt/pr78373.C
@@ -0,0 +1,22 @@
+// PR c++/78373
+// { dg-do compile { target c++11 } }
+
+struct A {
+  static A singleton;
+};
+struct B {
+  void m_fn2();
+  virtual int m_fn1();
+};
+struct D : B {
+  static int m_fn3(int, int, int, A) {
+    D &self = singleton;
+    self.m_fn2();
+  }
+  static D singleton;
+};
+template <typename, typename> struct C { bool m_fn4() const; };
+template <typename Base, typename Traits> bool C<Base, Traits>::m_fn4() const {
+  Traits::m_fn3(0, 0, 0, Base::singleton);
+}
+template struct C<A, D>;