c++: improved return expression location

Stripping the location wrapper from retval meant we didn't have the
necessary location information for any conversion diagnostics.  We only need
the stripping for the named return value optimization, let's use the
unstripped expression for everything else.

gcc/cp/ChangeLog:

	* typeck.c (check_return_expr): Only strip location wrapper during
	NRV handling.

gcc/testsuite/ChangeLog:

	* g++.dg/cpp0x/pr65327.C: Adjust location.
	* g++.dg/cpp23/constexpr-nonlit4.C: Likewise.
	* g++.dg/cpp23/constexpr-nonlit5.C: Likewise.
	* g++.dg/cpp2a/constexpr-init1.C: Likewise.

5 files changed, 18 insertions, 17 deletions

diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 58919aa..63a0eae 100644
--- a/gcc/cp/typeck.c
+++ b/gcc/cp/typeck.c
@@ -10545,19 +10545,20 @@ check_return_expr (tree retval, bool *no_warning)
      this restriction, anyway.  (jason 2000-11-19)
 
      See finish_function and finalize_nrv for the rest of this optimization.  */
+  tree bare_retval = NULL_TREE;
   if (retval)
     {
       retval = maybe_undo_parenthesized_ref (retval);
-      STRIP_ANY_LOCATION_WRAPPER (retval);
+      bare_retval = tree_strip_any_location_wrapper (retval);
     }
 
-  bool named_return_value_okay_p = can_do_nrvo_p (retval, functype);
+  bool named_return_value_okay_p = can_do_nrvo_p (bare_retval, functype);
   if (fn_returns_value_p && flag_elide_constructors)
     {
       if (named_return_value_okay_p
           && (current_function_return_value == NULL_TREE
-              || current_function_return_value == retval))
-	current_function_return_value = retval;
+	      || current_function_return_value == bare_retval))
+	current_function_return_value = bare_retval;
       else
 	current_function_return_value = error_mark_node;
     }
@@ -10571,7 +10572,7 @@ check_return_expr (tree retval, bool *no_warning)
     maybe_warn_pessimizing_move (retval, functype);
 
   /* Do any required conversions.  */
-  if (retval == result || DECL_CONSTRUCTOR_P (current_function_decl))
+  if (bare_retval == result || DECL_CONSTRUCTOR_P (current_function_decl))
     /* No conversions are required.  */
     ;
   else
diff --git a/gcc/testsuite/g++.dg/cpp0x/pr65327.C b/gcc/testsuite/g++.dg/cpp0x/pr65327.C
index 6e888eb..e814995 100644
--- a/gcc/testsuite/g++.dg/cpp0x/pr65327.C
+++ b/gcc/testsuite/g++.dg/cpp0x/pr65327.C
@@ -14,5 +14,5 @@ foo ()
 constexpr volatile int // { dg-warning "deprecated" "" { target c++2a } }
 bar ()
 {
-  return i;
-} // { dg-error "lvalue-to-rvalue conversion of a volatile lvalue" }
+  return i;  // { dg-error "lvalue-to-rvalue conversion of a volatile lvalue" }
+}
diff --git a/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit4.C b/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit4.C
index e4ed2e3..bdc97a9 100644
--- a/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit4.C
+++ b/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit4.C
@@ -34,7 +34,7 @@ baz (int x)
     {
       static const int v = qux ();	// { dg-message "'v' was not initialized with a constant expression" }
     case 12:
-      return v;
+      return v;	// { dg-error "the value of 'v' is not usable in a constant expression" }
     }
   return 0;
 }
@@ -46,12 +46,12 @@ corge (int x)
     {
       const thread_local int v = qux ();	// { dg-message "'v' was not initialized with a constant expression" }
     case 12:
-      return v;
+      return v; // { dg-error "the value of 'v' is not usable in a constant expression" }
     }
   return 0;
 }
 
 constexpr int a = foo (12);
 constexpr int b = bar (12);
-constexpr int c = baz (12);		// { dg-error "the value of 'v' is not usable in a constant expression" }
-constexpr int d = corge (12);		// { dg-error "the value of 'v' is not usable in a constant expression" }
+constexpr int c = baz (12);
+constexpr int d = corge (12);
diff --git a/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit5.C b/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit5.C
index 838f282..86d5dba 100644
--- a/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit5.C
+++ b/gcc/testsuite/g++.dg/cpp23/constexpr-nonlit5.C
@@ -34,7 +34,7 @@ baz (int x)
     {
       static int v = 6;	// { dg-message "int v' is not const" }
     case 12:
-      return v;
+      return v;	// { dg-error "the value of 'v' is not usable in a constant expression" }
     }
   return 0;
 }
@@ -46,12 +46,12 @@ corge (int x)
     {
       thread_local int v = 6;	// { dg-message "int v' is not const" }
     case 12:
-      return v;
+      return v;	// { dg-error "the value of 'v' is not usable in a constant expression" }
     }
   return 0;
 }
 
 constexpr int a = foo (12);
 constexpr int b = bar (12);
-constexpr int c = baz (12);		// { dg-error "the value of 'v' is not usable in a constant expression" }
-constexpr int d = corge (12);		// { dg-error "the value of 'v' is not usable in a constant expression" }
+constexpr int c = baz (12);
+constexpr int d = corge (12);
diff --git a/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C b/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
index 75984a2..e56ecfe 100644
--- a/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
+++ b/gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C
@@ -73,11 +73,11 @@ fn7 (bool b)
   int a; // { dg-message ".int a. is not const" }
   if (b)
     a = 42;
-  return a;
+  return a;		       // { dg-error "the value of .a. is not usable" }
 }
 
 static_assert (fn7 (true) == 42);
-static_assert (fn7 (false) == 42); // { dg-error "non-constant condition|the value of .a. is not usable" }
+static_assert (fn7 (false) == 42); // { dg-error "non-constant condition" }
 // { dg-message "in .constexpr. expansion of" "" { target *-*-* } .-1 }
 
 constexpr int