c++: Avoid -Wreturn-type warning if a template fn calls noreturn template fn [PR94742]

finish_call_expr already has code to set current_function_returns_abnormally
if a template calls a noreturn function, but on the following testcase it
doesn't call a FUNCTION_DECL, but TEMPLATE_DECL instead, in which case
we didn't check noreturn at all and just assumed it could return.

2020-04-25  Jakub Jelinek  <jakub@redhat.com>

	PR c++/94742
	* semantics.c (finish_call_expr): When looking if all overloads
	are noreturn, use STRIP_TEMPLATE to look through TEMPLATE_DECLs.

	* g++.dg/warn/Wreturn-type-12.C: New test.

diff --git a/gcc/cp/ChangeLog b/gcc/cp/ChangeLog
index 4d3049e67f353585f55fd014c7049349b9d970c3..5b9ff5a694cde14679a13ee735341fe1e934304b 100644 (file)
--- a/gcc/cp/ChangeLog
+++ b/gcc/cp/ChangeLog
@@ -1,3 +1,9 @@
+2020-04-25  Jakub Jelinek  <jakub@redhat.com>
+
+       PR c++/94742
+       * semantics.c (finish_call_expr): When looking if all overloads
+       are noreturn, use STRIP_TEMPLATE to look through TEMPLATE_DECLs.
+
 2020-04-24  Martin Liska  <mliska@suse.cz>
 
        * coroutines.cc: Fix compilation error for release checking

diff --git a/gcc/cp/semantics.c b/gcc/cp/semantics.c
index c7a6064e9f338bdf5a12b421c4e15ba5b6f7f492..64a7b76d43783788be3b2ffb8e96962fd83cf1e4 100644 (file)
--- a/gcc/cp/semantics.c
+++ b/gcc/cp/semantics.c
@@ -2508,7 +2508,7 @@ finish_call_expr (tree fn, vec<tree, va_gc> **args, bool disallow_virtual,
              bool abnormal = true;
              for (lkp_iterator iter (fn); abnormal && iter; ++iter)
                {
-                 tree fndecl = *iter;
+                 tree fndecl = STRIP_TEMPLATE (*iter);
                  if (TREE_CODE (fndecl) != FUNCTION_DECL
                      || !TREE_THIS_VOLATILE (fndecl))
                    abnormal = false;

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index fa583670bafc333e323b60766c1ba3dc476296be..b9be66865cda9ff54f9667a6bb35a7cbf0c16296 100644 (file)
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,5 +1,8 @@
 2020-04-25  Jakub Jelinek  <jakub@redhat.com>
 
+       PR c++/94742
+       * g++.dg/warn/Wreturn-type-12.C: New test.
+
        PR tree-optimization/94734
        PR tree-optimization/89430
        * gcc.dg/tree-ssa/pr89430-1.c: Add xfail.

diff --git a/gcc/testsuite/g++.dg/warn/Wreturn-type-12.C b/gcc/testsuite/g++.dg/warn/Wreturn-type-12.C
new file mode 100644 (file)
index 0000000..b35d3fa
--- /dev/null
+++ b/gcc/testsuite/g++.dg/warn/Wreturn-type-12.C
@@ -0,0 +1,23 @@
+// PR c++/94742
+// { dg-do compile { target c++11 } }
+// { dg-options "-Wreturn-type" }
+
+template <class T>
+[[noreturn]] void
+foo (T const &t, char const *)
+{
+  throw T (t);
+}
+
+template <class U>
+int
+bar ()
+{
+  foo (42, __FUNCTION__);
+}      // { dg-bogus "no return statement in function returning non-void" }
+
+int
+main ()
+{
+  bar<long>();
+}