[PR c++/82878] pass-by-invisiref in lambda

https://gcc.gnu.org/ml/gcc-patches/2017-11/msg01115.html
	PR c++/82878
	PR c++/78495
	* call.c (build_call_a): Don't set CALL_FROM_THUNK_P for inherited
	ctor.
	* cp-gimplify.c	(cp_genericize_r): Restore THUNK dereference
	inhibibition check removed in previous c++/78495 change.

	PR c++/82878
	* g++.dg/cpp0x/pr82878.C: New.
	* g++.dg/cpp1z/inh-ctor38.C: Check moves too.

From-SVN: r254958

gcc/cp/ChangeLog

+2017-11-20  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/82878
+	PR c++/78495
+	* call.c (build_call_a): Don't set CALL_FROM_THUNK_P for inherited
+	ctor.
+	* cp-gimplify.c	(cp_genericize_r): Restore THUNK dereference
+	inhibibition check removed in previous c++/78495 change.
+
 2017-11-20   Jakub Jelinek  <jakub@redhat.com>
 
 	PR c++/82781

gcc/cp/call.c

@@ -376,18 +376,10 @@ build_call_a (tree function, int n, tree *argarray)
 
   TREE_HAS_CONSTRUCTOR (function) = (decl && DECL_CONSTRUCTOR_P (decl));
 
-  if (current_function_decl && decl
-      && flag_new_inheriting_ctors
-      && DECL_INHERITED_CTOR (current_function_decl)
-      && (DECL_INHERITED_CTOR (current_function_decl)
-	  == DECL_CLONED_FUNCTION (decl)))
-    /* Pass arguments directly to the inherited constructor.  */
-    CALL_FROM_THUNK_P (function) = true;
-
   /* Don't pass empty class objects by value.  This is useful
      for tags in STL, which are used to control overload resolution.
      We don't need to handle other cases of copying empty classes.  */
-  else if (! decl || ! DECL_BUILT_IN (decl))
+  if (! decl || ! DECL_BUILT_IN (decl))
     for (i = 0; i < n; i++)
       {
 	tree arg = CALL_EXPR_ARG (function, i);

gcc/cp/cp-gimplify.c

@@ -1078,6 +1078,14 @@ cp_genericize_r (tree *stmt_p, int *walk_subtrees, void *data)
       && omp_var_to_track (stmt))
     omp_cxx_notice_variable (wtd->omp_ctx, stmt);
 
+  /* Don't dereference parms in a thunk, pass the references through. */
+  if ((TREE_CODE (stmt) == CALL_EXPR && CALL_FROM_THUNK_P (stmt))
+      || (TREE_CODE (stmt) == AGGR_INIT_EXPR && AGGR_INIT_FROM_THUNK_P (stmt)))
+    {
+      *walk_subtrees = 0;
+      return NULL;
+    }
+
   /* Dereference invisible reference parms.  */
   if (wtd->handle_invisiref_parm_p && is_invisiref_parm (stmt))
     {

gcc/cp/lambda.c

@@ -1103,7 +1103,6 @@ maybe_add_lambda_conv_op (tree type)
       }
   }
 
-
   if (generic_lambda_p)
     {
       if (decltype_call)

gcc/testsuite/ChangeLog

+2017-11-20  Nathan Sidwell  <nathan@acm.org>
+
+	PR c++/82878
+	* g++.dg/cpp0x/pr82878.C: New.
+	* g++.dg/cpp1z/inh-ctor38.C: Check moves too.
+
 2017-11-20  Bin Cheng  <bin.cheng@arm.com>
 
 	* gcc.dg/tree-ssa/predcom-dse-12.c: New test.

gcc/testsuite/g++.dg/cpp0x/lambda/lambda-switch.C

@@ -20,7 +20,7 @@ main ()
 	    {
 	    case 3:		// { dg-error "case" }
 	      break;		// { dg-error "break" }
-	    };
+	    };		// { dg-warning "statement will never be executed" }
 	}
     }
 }

gcc/testsuite/g++.dg/cpp0x/pr82878.C

+// { dg-do compile { target c++11 } }
+// { dg-additional-options "-O" }
+// pr 82878 erroneously unwrapped a reference parm in the lambda::_FUN
+// thunk.
+
+struct A {
+  ~A();
+  operator int ();
+};
+
+void baz ();
+
+void
+bar (A b)
+{
+  void (*lam) (A) = [](A) { baz (); };
+
+  if (auto c = b)
+    lam (c);
+}

gcc/testsuite/g++.dg/cpp1z/inh-ctor38.C

 // { dg-do run { target c++11 } }
 // PR78495 failed to propagate pass-by-value struct to base ctor.
 
+static int moves = 0;
+
 struct Ptr {
   void *ptr = 0;
 
   Ptr() {}
   Ptr(Ptr const&) = delete;
-  Ptr(Ptr&& other) : ptr (other.ptr) {}
+  Ptr(Ptr&& other) : ptr (other.ptr) {moves++;}
 };
 
 struct Base {
   Ptr val;
-  Base(Ptr val_) : val(static_cast<Ptr&&>(val_)) {}
+  Base(Ptr val_);
 };
 
 struct Derived: Base {
@@ -27,5 +29,13 @@ void *Foo () {
 }
 
 int main () {
-  return Foo () != 0;
+  if (Foo ())
+    return 1;
+
+  if (moves != 2)
+    return 2;
+
+  return 0;
 }
+
+Base::Base(Ptr val_) : val(static_cast<Ptr&&>(val_)) {}