[gcc(refs/vendors/ibm/heads/perf)] libstdc++: Fix use of inaccessible private member in split_view (PR93936)

[Jiu Fu Guo]

https://gcc.gnu.org/g:8ce13842b50cbd2676f2e322995182af20df31fe

commit 8ce13842b50cbd2676f2e322995182af20df31fe
Author: Patrick Palka <ppalka@redhat.com>
Date:   Wed Feb 26 08:38:06 2020 -0500

    libstdc++: Fix use of inaccessible private member in split_view (PR93936)
    
    We are calling _OuterIter::__current from _InnerIter::operator==, but the former
    is private within this non-member friend.  Fix this by calling
    _OuterIter::operator== instead, which does the right thing here.
    
    libstdc++-v3/ChangeLog:
    
            PR libstdc++/93936
            * include/std/ranges (split_view::_InnerIter::operator==): Compare
            the operands' _M_i rather than their _M_i.current().
            * testsuite/std/ranges/adaptors/split.cc: Augment test.

Diff:
---
 libstdc++-v3/ChangeLog                              |  5 +++++
 libstdc++-v3/include/std/ranges                     |  2 +-
 libstdc++-v3/testsuite/std/ranges/adaptors/split.cc | 18 ++++++++++++++++++
 3 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/ChangeLog b/libstdc++-v3/ChangeLog
index 8af27d4cc52..49f2b59e3ae 100644
--- a/libstdc++-v3/ChangeLog
+++ b/libstdc++-v3/ChangeLog
@@ -1,5 +1,10 @@
 2020-02-26  Patrick Palka  <ppalka@redhat.com>
 
+	PR libstdc++/93936
+	* include/std/ranges (split_view::_InnerIter::operator==): Compare
+	the operands' _M_i rather than their _M_i.current().
+	* testsuite/std/ranges/adaptors/split.cc: Augment test.
+
 	P1645R1 constexpr for <numeric> algorithms
 	* include/bits/stl_numeric.h (iota, accumulate, inner_product,
 	partial_sum, adjacent_difference): Make conditionally constexpr for
diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index d8326632166..bad89c5b8b0 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -2841,7 +2841,7 @@ namespace views
 	  friend constexpr bool
 	  operator==(const _InnerIter& __x, const _InnerIter& __y)
 	    requires forward_range<_Base>
-	  { return __x._M_i.__current() == __y._M_i.__current(); }
+	  { return __x._M_i == __y._M_i; }
 
 	  friend constexpr bool
 	  operator==(const _InnerIter& __x, default_sentinel_t)
diff --git a/libstdc++-v3/testsuite/std/ranges/adaptors/split.cc b/libstdc++-v3/testsuite/std/ranges/adaptors/split.cc
index e25031c0aea..52b015cf0c6 100644
--- a/libstdc++-v3/testsuite/std/ranges/adaptors/split.cc
+++ b/libstdc++-v3/testsuite/std/ranges/adaptors/split.cc
@@ -91,6 +91,23 @@ test04()
   VERIFY( i == v.end() );
 }
 
+void
+test05()
+{
+  auto as_string = [](ranges::view auto rng) {
+    auto in = rng | views::common;
+    return std::string(in.begin(), in.end());
+  };
+  std::string str
+    = "Now is the time for all good men to come to the aid of their county.";
+  auto rng
+    = str | views::split(' ') | views::transform(as_string) | views::common;
+  std::vector<std::string> words(rng.begin(), rng.end());
+  auto not_space_p = [](char c) { return c != ' '; };
+  VERIFY( ranges::equal(words | views::join,
+			str | views::filter(not_space_p)) );
+}
+
 int
 main()
 {
@@ -98,4 +115,5 @@ main()
   test02();
   test03();
   test04();
+  test05();
 }