diff --git a/gcc/cp/cp-gimplify.c b/gcc/cp/cp-gimplify.c
index 0a002db14e709882ae12cc341a1a24183ef19d99..e3ede02a48ebb0815c42b1b4758c0499b4aca0e6 100644
--- a/gcc/cp/cp-gimplify.c
+++ b/gcc/cp/cp-gimplify.c
@@ -2421,7 +2421,8 @@ cp_fold (tree x)
if (REF_PARENTHESIZED_P (x))
{
tree p = maybe_undo_parenthesized_ref (x);
- return cp_fold (p);
+ if (p != x)
+ return cp_fold (p);
}
goto unary;
diff --git a/gcc/cp/pt.c b/gcc/cp/pt.c
index 6b560952639f5a2defcec64bc808dac756dabd62..d3efc6ea23805251dafc25aca1842e2003a5fdb4 100644
--- a/gcc/cp/pt.c
+++ b/gcc/cp/pt.c
@@ -29889,13 +29889,18 @@ do_auto_deduction (tree type, tree init, tree auto_node,
}
else if (AUTO_IS_DECLTYPE (auto_node))
{
+ /* Figure out if INIT is an unparenthesized id-expression or an
+ unparenthesized class member access. */
tree stripped_init = tree_strip_any_location_wrapper (init);
- if (REFERENCE_REF_P (stripped_init))
+ /* We need to be able to tell '(r)' and 'r' apart (when it's of
+ reference type). Only the latter is an id-expression. */
+ if (REFERENCE_REF_P (stripped_init)
+ && !REF_PARENTHESIZED_P (stripped_init))
stripped_init = TREE_OPERAND (stripped_init, 0);
- bool id = (DECL_P (stripped_init)
- || ((TREE_CODE (init) == COMPONENT_REF
- || TREE_CODE (init) == SCOPE_REF)
- && !REF_PARENTHESIZED_P (init)));
+ const bool id = (DECL_P (stripped_init)
+ || ((TREE_CODE (stripped_init) == COMPONENT_REF
+ || TREE_CODE (stripped_init) == SCOPE_REF)
+ && !REF_PARENTHESIZED_P (stripped_init)));
tree deduced = finish_decltype_type (init, id, complain);
deduced = canonicalize_type_argument (deduced, complain);
if (deduced == error_mark_node)
diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index cd1956497f8cfe0e60034d7b802ee6a7fb1e81c8..edba4b60e1090c0c737be6eb3183c639df60a446 100644
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -2049,7 +2049,8 @@ force_paren_expr (tree expr, bool even_uneval)
return expr;
if (TREE_CODE (expr) == COMPONENT_REF
- || TREE_CODE (expr) == SCOPE_REF)
+ || TREE_CODE (expr) == SCOPE_REF
+ || REFERENCE_REF_P (expr))
REF_PARENTHESIZED_P (expr) = true;
else if (DECL_P (tree_strip_any_location_wrapper (expr)))
{
@@ -2072,19 +2073,8 @@ maybe_undo_parenthesized_ref (tree t)
if (cxx_dialect < cxx14)
return t;
- if (INDIRECT_REF_P (t) && REF_PARENTHESIZED_P (t))
- {
- t = TREE_OPERAND (t, 0);
- while (TREE_CODE (t) == NON_LVALUE_EXPR
- || TREE_CODE (t) == NOP_EXPR)
- t = TREE_OPERAND (t, 0);
-
- gcc_assert (TREE_CODE (t) == ADDR_EXPR
- || TREE_CODE (t) == STATIC_CAST_EXPR);
- t = TREE_OPERAND (t, 0);
- }
- else if ((TREE_CODE (t) == PAREN_EXPR || TREE_CODE (t) == VIEW_CONVERT_EXPR)
- && REF_PARENTHESIZED_P (t))
+ if ((TREE_CODE (t) == PAREN_EXPR || TREE_CODE (t) == VIEW_CONVERT_EXPR)
+ && REF_PARENTHESIZED_P (t))
t = TREE_OPERAND (t, 0);
return t;
diff --git a/gcc/testsuite/g++.dg/cpp1y/decltype-auto2.C b/gcc/testsuite/g++.dg/cpp1y/decltype-auto2.C
new file mode 100644
index 0000000000000000000000000000000000000000..56e011e36f4622f1b47371c69f8cb687751a2c0e
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/decltype-auto2.C
@@ -0,0 +1,12 @@
+// PR c++/103403
+// { dg-do compile { target c++14 } }
+
+template<typename T>
+auto constexpr RtoL1(T&& r) -> decltype(auto) {
+ return (r);
+};
+int main() {
+ int t;
+ int x{3};
+ decltype (RtoL1(x+0)) y = t;
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/decltype-auto3.C b/gcc/testsuite/g++.dg/cpp1y/decltype-auto3.C
new file mode 100644
index 0000000000000000000000000000000000000000..914e87f5b79c34c706ecb2aab1547ed7291d9fe4
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/decltype-auto3.C
@@ -0,0 +1,12 @@
+// PR c++/103403
+// { dg-do compile { target c++14 } }
+
+int main()
+{
+ int i = 1;
+ int&& r = 1;
+
+ decltype(auto) ri = (i);
+ decltype(auto) rr = (r);
+ decltype((r)) rr2 = (r);
+}
diff --git a/gcc/testsuite/g++.dg/cpp1y/decltype-auto4.C b/gcc/testsuite/g++.dg/cpp1y/decltype-auto4.C
new file mode 100644
index 0000000000000000000000000000000000000000..9765857efb199958223f8db6bcb9f256fc06d67c
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1y/decltype-auto4.C
@@ -0,0 +1,65 @@
+// PR c++/103403
+// { dg-do compile { target c++14 } }
+
+struct false_type { static constexpr bool value = false; };
+struct true_type { static constexpr bool value = true; };
+template<class T, class U>
+struct is_same : false_type {};
+template<class T>
+struct is_same<T, T> : true_type {};
+
+int fn ();
+int &ref ();
+int &&rref ();
+
+struct S {
+ int i;
+ int &r = i;
+};
+
+void
+ids ()
+{
+ const S *s = new S();
+ int i;
+ int &ir = i;
+ decltype(auto) r1 = s->i;
+ static_assert (is_same<decltype(r1), int>::value, "");
+ decltype(auto) r2 = s->r;
+ static_assert (is_same<decltype(r2), int&>::value, "");
+ decltype(auto) r3 = i;
+ static_assert (is_same<decltype(r3), int>::value, "");
+ decltype(auto) r4 = ir;
+ static_assert (is_same<decltype(r4), int&>::value, "");
+}
+
+void
+nonids ()
+{
+ const S *s = new S();
+ int i;
+ int &ir = i;
+ int &&irr = 42;
+ decltype(auto) r1 = fn ();
+ static_assert (is_same<decltype(r1), int>::value, "");
+ decltype(auto) r2 = (fn ());
+ static_assert (is_same<decltype(r2), int>::value, "");
+ decltype(auto) r3 = ref ();
+ static_assert (is_same<decltype(r3), int&>::value, "");
+ decltype(auto) r4 = (ref ());
+ static_assert (is_same<decltype(r4), int&>::value, "");
+ decltype(auto) r5 = rref ();
+ static_assert (is_same<decltype(r5), int&&>::value, "");
+ decltype(auto) r6 = (rref ());
+ static_assert (is_same<decltype(r6), int&&>::value, "");
+ decltype(auto) r8 = (s->i);
+ static_assert (is_same<decltype(r8), const int&>::value, "");
+ decltype(auto) r9 = (s->r);
+ static_assert (is_same<decltype(r9), int&>::value, "");
+ decltype(auto) r10 = (i);
+ static_assert (is_same<decltype(r10), int&>::value, "");
+ decltype(auto) r11 = (ir);
+ static_assert (is_same<decltype(r11), int&>::value, "");
+ decltype(auto) r12 = (irr);
+ static_assert (is_same<decltype(r12), int&>::value, "");
+}
diff --git a/gcc/testsuite/g++.dg/cpp1z/decomp-decltype1.C b/gcc/testsuite/g++.dg/cpp1z/decomp-decltype1.C
new file mode 100644
index 0000000000000000000000000000000000000000..e8ca0fc0beeb91ff770bf7d1081a6d0df29b241d
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp1z/decomp-decltype1.C
@@ -0,0 +1,28 @@
+// PR c++/81176
+// { dg-do compile { target c++17 } }
+
+namespace std {
+ template<typename T> struct tuple_size;
+ template<int, typename> struct tuple_element;
+}
+
+struct A {
+ int i;
+ template <int I> int& get() { return i; }
+};
+
+template<> struct std::tuple_size<A> { static const int value = 2; };
+template<int I> struct std::tuple_element<I,A> { using type = int; };
+
+template <class,class> struct same_type;
+template <class T> struct same_type<T,T> {};
+
+void
+foo (A x)
+{
+ auto [ a, b ] = x;
+ decltype(auto) c = a;
+ same_type<decltype(a), int>{};
+ same_type<decltype(c), int>{};
+}
+