[PATCH] testsuite: Add test for r11-4123

[Marek Polacek <polacek@redhat.com>]

r11-4123 came without a test but I happened upon a nice test case that
got fixed by that revision.  So I think it'd be good to add it.  The
ICE was:

phi-1.C: In constructor 'ElementManager::ElementManager()':
phi-1.C:28:1: error: missing definition
   28 | ElementManager::ElementManager() : array_(makeArray()) {}
      | ^~~~~~~~~~~~~~
for SSA_NAME: _12 in statement:
_10 = PHI <_12(3), _11(5)>
PHI argument
_12
for PHI node
_10 = PHI <_12(3), _11(5)>
during GIMPLE pass: fixup_cfg
phi-1.C:28:1: internal compiler error: verify_ssa failed

Incidentally, do you think it's safe to backport r11-4123 to GCC 8
(downstream)?  Thanks.

Tested on x86_64-pc-linux-gnu, ok for trunk?

gcc/testsuite/ChangeLog:

	* g++.dg/tree-ssa/phi-1.C: New test.
---
 gcc/testsuite/g++.dg/tree-ssa/phi-1.C | 28 +++++++++++++++++++++++++++
 1 file changed, 28 insertions(+)
 create mode 100644 gcc/testsuite/g++.dg/tree-ssa/phi-1.C

diff --git a/gcc/testsuite/g++.dg/tree-ssa/phi-1.C b/gcc/testsuite/g++.dg/tree-ssa/phi-1.C
new file mode 100644
index 00000000000..26cade052e3
--- /dev/null
+++ b/gcc/testsuite/g++.dg/tree-ssa/phi-1.C
@@ -0,0 +1,28 @@
+// { dg-do compile { target c++11 } }
+// { dg-options "-O --param early-inlining-insns=14" }
+
+struct Element;
+template <int _Nm> struct __array_traits { typedef Element _Type[_Nm]; };
+template <int _Nm> struct array {
+  typename __array_traits<_Nm>::_Type _M_elems;
+};
+bool logLevel();
+struct LogCapture {
+  void stream();
+};
+struct Element {
+  Element();
+  long data_;
+};
+using ElementArray = array<6>;
+struct ElementManager {
+  ElementManager();
+  ElementArray array_;
+};
+static ElementArray makeArray() {
+  if (logLevel())
+    LogCapture().stream();
+  ElementArray foo;
+  return foo;
+}
+ElementManager::ElementManager() : array_(makeArray()) {}

base-commit: b6316324fceaef431799a8b386de5cc9881d6898
-- 
2.37.2