[pushed] c++: improved return expression location

Jason Merrill jason@redhat.com
Mon Nov 22 22:43:05 GMT 2021


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.

Tested x86_64-pc-linux-gnu, applying to trunk.

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.
---
 gcc/cp/typeck.c                                | 11 ++++++-----
 gcc/testsuite/g++.dg/cpp0x/pr65327.C           |  4 ++--
 gcc/testsuite/g++.dg/cpp23/constexpr-nonlit4.C |  8 ++++----
 gcc/testsuite/g++.dg/cpp23/constexpr-nonlit5.C |  8 ++++----
 gcc/testsuite/g++.dg/cpp2a/constexpr-init1.C   |  4 ++--
 5 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/gcc/cp/typeck.c b/gcc/cp/typeck.c
index 58919aaf13e..63a0eaef2da 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 6e888ebff2c..e8149953ffd 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 e4ed2e36c30..bdc97a9bc79 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 838f282c1f9..86d5dba77a3 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 75984a2fdcb..e56ecfed48a 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

base-commit: a6e0d593707ae44dec0bdf2bcdc4f539050b46db
-- 
2.27.0



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