Re: [PATCH 1/4] libstdc++: Reduce the size of an unbounded iota_view

[Jonathan Wakely via Gcc-patches]

On 28/09/20 00:48 -0400, Patrick Palka via Libstdc++ wrote:

libstdc++-v3/ChangeLog:

* include/std/ranges (iota_view::_M_bound): Give it
[[no_unique_address]].
* testsuite/std/ranges/iota/iota_view.cc: Check that an
unbounded iota_view has minimal size.


OK.


libstdc++-v3/include/std/ranges | 2 +-
libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc | 3 +++
2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index ed04fa0001d..964a2b616a6 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -511,7 +511,7 @@ namespace ranges
  };

  _Winc _M_value = _Winc();
-  _Bound _M_bound = _Bound();
+  [[no_unique_address]] _Bound _M_bound = _Bound();

public:
  iota_view() = default;
diff --git a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc 
b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
index 65d166fbd3b..8a33e10a093 100644
--- a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
+++ b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
@@ -77,6 +77,9 @@ test04()
  VERIFY( it == v.end() );
}

+// Verify we optimize away the 'bound' data member of an unbounded iota_view.
+static_assert(sizeof(std::ranges::iota_view) == 1);
+
int
main()
{
--
2.28.0.618.g9bc233ae1c

[PATCH 1/4] libstdc++: Reduce the size of an unbounded iota_view

[Patrick Palka via Gcc-patches]

libstdc++-v3/ChangeLog:

* include/std/ranges (iota_view::_M_bound): Give it
[[no_unique_address]].
* testsuite/std/ranges/iota/iota_view.cc: Check that an
unbounded iota_view has minimal size.
---
 libstdc++-v3/include/std/ranges | 2 +-
 libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc | 3 +++
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/libstdc++-v3/include/std/ranges b/libstdc++-v3/include/std/ranges
index ed04fa0001d..964a2b616a6 100644
--- a/libstdc++-v3/include/std/ranges
+++ b/libstdc++-v3/include/std/ranges
@@ -511,7 +511,7 @@ namespace ranges
   };
 
   _Winc _M_value = _Winc();
-  _Bound _M_bound = _Bound();
+  [[no_unique_address]] _Bound _M_bound = _Bound();
 
 public:
   iota_view() = default;
diff --git a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc 
b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
index 65d166fbd3b..8a33e10a093 100644
--- a/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
+++ b/libstdc++-v3/testsuite/std/ranges/iota/iota_view.cc
@@ -77,6 +77,9 @@ test04()
   VERIFY( it == v.end() );
 }
 
+// Verify we optimize away the 'bound' data member of an unbounded iota_view.
+static_assert(sizeof(std::ranges::iota_view) == 1);
+
 int
 main()
 {
-- 
2.28.0.618.g9bc233ae1c