[gcc(refs/vendors/ibm/heads/perf)] c++: Add test for DR 1423, Convertibility of nullptr to bool.

[Jiu Fu Guo]

https://gcc.gnu.org/g:b9934ad88d6b27e5cf1a34d88dbefb2bbe928753

commit b9934ad88d6b27e5cf1a34d88dbefb2bbe928753
Author: Marek Polacek <polacek@redhat.com>
Date:   Mon Feb 24 12:56:00 2020 -0500

    c++: Add test for DR 1423, Convertibility of nullptr to bool.
    
    DR 1423, which supersedes DR 654, says that you can't copy-init
    a bool from a std::nullptr_t:
    
      bool b = nullptr;  // error
    
    Conversely, it works with direct-initialization which is more
    permissive than copy-initialization.
    
    No code changes necessary since we handle it right.
    
    2020-02-26  Marek Polacek  <polacek@redhat.com>
    
            DR 1423, Convertibility of nullptr to bool.
            * g++.dg/DRs/dr1423.C: New test.

Diff:
---
 gcc/testsuite/ChangeLog           | 5 +++++
 gcc/testsuite/g++.dg/DRs/dr1423.C | 7 +++++++
 2 files changed, 12 insertions(+)

diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index 4f46c385403..a18b1f2ef89 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,8 @@
+2020-02-26  Marek Polacek  <polacek@redhat.com>
+
+	DR 1423, Convertibility of nullptr to bool.
+	* g++.dg/DRs/dr1423.C: New test.
+
 2020-02-26  Marek Polacek  <polacek@redhat.com>
 
 	PR c++/93803 - ICE with constexpr init and [[no_unique_address]].
diff --git a/gcc/testsuite/g++.dg/DRs/dr1423.C b/gcc/testsuite/g++.dg/DRs/dr1423.C
new file mode 100644
index 00000000000..d82baae9985
--- /dev/null
+++ b/gcc/testsuite/g++.dg/DRs/dr1423.C
@@ -0,0 +1,7 @@
+// DR 1423 - Convertibility of nullptr to bool.
+// { dg-do compile { target c++11 } }
+
+bool b = nullptr; // { dg-error "converting to .bool. from .std::nullptr_t. requires direct-initialization" }
+bool b2(nullptr);
+bool b3{nullptr};
+bool b4 = { nullptr }; // { dg-error "converting to .bool. from .std::nullptr_t. requires direct-initialization" }