From: Jakub Jelinek <jakub@redhat.com>
Date: Wed, 22 Jan 2020 16:39:55 +0000 (+0100)
Subject: re PR c++/92992 (Side-effects dropped when decltype(nullptr) typed expression is... 
X-Git-Tag: releases/gcc-9.3.0~206
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=beee53d59e32e7859b32b19bc7e222e3d04cc5f0;p=thirdparty%2Fgcc.git

re PR c++/92992 (Side-effects dropped when decltype(nullptr) typed expression is passed to ellipsis)

	PR c++/92992
	* call.c (convert_arg_to_ellipsis): For decltype(nullptr) arguments
	that have side-effects use cp_build_compound_expr.

	* g++.dg/cpp0x/nullptr45.C: New test.
---

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 0e1557c936e2..f0e314fd3548 100644
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,12 @@
+2020-01-22  Jakub Jelinek  <jakub@redhat.com>
+
+	Backported from mainline
+	2019-12-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92992
+	* call.c (convert_arg_to_ellipsis): For decltype(nullptr) arguments
+	that have side-effects use cp_build_compound_expr.
+
 2020-01-21  Jason Merrill  <jason@redhat.com>
 
 	PR c++/91476 - anon-namespace reference temp clash between TUs.
diff --git a/gcc/cp/call.c b/gcc/cp/call.c
index 8e14e89d5d49..787a7ed387bd 100644
--- a/gcc/cp/call.c
+++ b/gcc/cp/call.c
@@ -7543,7 +7543,12 @@ convert_arg_to_ellipsis (tree arg, tsubst_flags_t complain)
       arg = convert_to_real_nofold (double_type_node, arg);
     }
   else if (NULLPTR_TYPE_P (arg_type))
-    arg = null_pointer_node;
+    {
+      if (TREE_SIDE_EFFECTS (arg))
+	arg = cp_build_compound_expr (arg, null_pointer_node, complain);
+      else
+	arg = null_pointer_node;
+    }
   else if (INTEGRAL_OR_ENUMERATION_TYPE_P (arg_type))
     {
       if (SCOPED_ENUM_P (arg_type))
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index d76c05982452..2e507fdfe505 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,11 @@
+2020-01-22  Jakub Jelinek  <jakub@redhat.com>
+
+	Backported from mainline
+	2019-12-20  Jakub Jelinek  <jakub@redhat.com>
+
+	PR c++/92992
+	* g++.dg/cpp0x/nullptr45.C: New test.
+
 2020-01-22  Joseph Myers  <joseph@codesourcery.com>
 
 	Backport from mainline:
diff --git a/gcc/testsuite/g++.dg/cpp0x/nullptr45.C b/gcc/testsuite/g++.dg/cpp0x/nullptr45.C
new file mode 100644
index 000000000000..3ff226803dff
--- /dev/null
+++ b/gcc/testsuite/g++.dg/cpp0x/nullptr45.C
@@ -0,0 +1,24 @@
+// PR c++/92992
+// { dg-do run { target c++11 } }
+
+int a;
+
+void
+bar (int, ...)
+{
+}
+
+decltype (nullptr)
+baz ()
+{
+  a++;
+  return nullptr;
+}
+
+int
+main ()
+{
+  bar (0, baz ());
+  if (a != 1)
+    __builtin_abort ();
+}