[gcc(refs/users/marxin/heads/marxin-gcc-benchmark-branch)] coroutines: Ensure the ramp return object is checked (PR93443).

[Martin Liska]

https://gcc.gnu.org/g:1f2e84238c9f079747804026b6225ec8c1d0e4b7

commit 1f2e84238c9f079747804026b6225ec8c1d0e4b7
Author: Iain Sandoe <iain@sandoe.co.uk>
Date:   Mon Jan 27 10:13:09 2020 +0000

    coroutines: Ensure the ramp return object is checked (PR93443).
    
    As the PR shows, there is a pathway through the code where the
    no_warning value is not set, which corresponds to a missing check
    of the ramp return when it was constructed from the 'get return
    object'  Fixed by ensuring that the check of the return value is
    carried out for both return cases.
    
    gcc/cp/ChangeLog:
    
    2020-01-27  Iain Sandoe  <iain@sandoe.co.uk>
    
            PR c++/93443
            * coroutines.cc (morph_fn_to_coro): Check the ramp return
            value when it is constructed from the 'get return object'.

Diff:
---
 gcc/cp/ChangeLog     |  6 ++++++
 gcc/cp/coroutines.cc | 18 ++++++++++--------
 2 files changed, 16 insertions(+), 8 deletions(-)

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 5324a6e574e..b1bf4a0adff 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-01-27  Iain Sandoe  <iain@sandoe.co.uk>
+
+	PR c++/93443
+	* coroutines.cc (morph_fn_to_coro): Check the ramp return
+	value when it is constructed from the 'get return object'.
+
 2020-01-27  Nathan Sidwell  <nathan@acm.org>
 
 	PR c++/91826
diff --git a/gcc/cp/coroutines.cc b/gcc/cp/coroutines.cc
index b222c1f7a8e..e8a6a4033f6 100644
--- a/gcc/cp/coroutines.cc
+++ b/gcc/cp/coroutines.cc
@@ -3526,14 +3526,9 @@ morph_fn_to_coro (tree orig, tree *resumer, tree *destroyer)
 
   /* Switch to using 'input_location' as the loc, since we're now more
      logically doing things related to the end of the function.  */
-  /* done, we just need the return value.  */
-  bool no_warning;
-  if (same_type_p (TREE_TYPE (gro), fn_return_type))
-    {
-      /* Already got the result.  */
-      r = check_return_expr (DECL_RESULT (orig), &no_warning);
-    }
-  else
+
+  /* The ramp is done, we just need the return value.  */
+  if (!same_type_p (TREE_TYPE (gro), fn_return_type))
     {
       /* construct the return value with a single GRO param.  */
       vec<tree, va_gc> *args = make_tree_vector_single (gro);
@@ -3545,6 +3540,13 @@ morph_fn_to_coro (tree orig, tree *resumer, tree *destroyer)
       add_stmt (r);
       release_tree_vector (args);
     }
+  /* Else the GRO is the return and we already built it in place.  */
+
+  bool no_warning;
+  r = check_return_expr (DECL_RESULT (orig), &no_warning);
+  if (error_operand_p (r) && warn_return_type)
+    /* Suppress -Wreturn-type for the ramp.  */
+    TREE_NO_WARNING (orig) = true;
 
   r = build_stmt (input_location, RETURN_EXPR, DECL_RESULT (orig));
   TREE_NO_WARNING (r) |= no_warning;