Tested powerpc64le-linux. Pusshed to trunk.
-- >8 --
My r14-1452-gfb409a15d9babc change to add optimization hints to
std::vector causes regressions because it makes std::vector::size() and
std::vector::capacity() too big to inline. That's the opposite of what
I wanted, so revert the changes to those functions.
To achieve the original aim of optimizing vec.assign(vec.size(), x) we
can add a local optimization hint to _M_fill_assign, so that it doesn't
affect all other uses of size() and capacity().
Additionally, add the same hint to the _M_assign_aux overload for
forward iterators and add that to the testcase.
It would be nice to similarly optimize:
if (vec1.size() == vec2.size()) vec1 = vec2;
but adding hints to operator=(const vector&) doesn't help. Presumably
the relationships between the two sizes and two capacities are too
complex to track effectively.
libstdc++-v3/ChangeLog:
PR libstdc++/110060
* include/bits/stl_vector.h (_Vector_base::_M_invariant):
Remove.
(vector::size, vector::capacity): Remove calls to _M_invariant.
* include/bits/vector.tcc (vector::_M_fill_assign): Add
optimization hint to reallocating path.
(vector::_M_assign_aux(FwdIter, FwdIter, forward_iterator_tag)):
Likewise.
* testsuite/23_containers/vector/capacity/invariant.cc: Moved
to...
* testsuite/23_containers/vector/modifiers/assign/no_realloc.cc:
...here. Check assign(FwdIter, FwdIter) too.
* testsuite/23_containers/vector/types/1.cc: Revert addition
of -Wno-stringop-overread option.
---
libstdc++-v3/include/bits/stl_vector.h | 23 +------------------
libstdc++-v3/include/bits/vector.tcc | 17 ++++++++++----
.../assign/no_realloc.cc} | 6 +++++
.../testsuite/23_containers/vector/types/1.cc | 2 +-
4 files changed, 20 insertions(+), 28 deletions(-)
rename libstdc++-v3/testsuite/23_containers/vector/{capacity/invariant.cc =>
modifiers/assign/no_realloc.cc} (70%)
diff --git a/libstdc++-v3/include/bits/stl_vector.h
b/libstdc++-v3/include/bits/stl_vector.h
index e593be443bc..70ced3d101f 100644
--- a/libstdc++-v3/include/bits/stl_vector.h
+++ b/libstdc++-v3/include/bits/stl_vector.h
@@ -389,23 +389,6 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
protected:
- __attribute__((__always_inline__))
- _GLIBCXX20_CONSTEXPR void
- _M_invariant() const
- {
-#if __OPTIMIZE__
- if (this->_M_impl._M_finish < this->_M_impl._M_start)
- __builtin_unreachable();
- if (this->_M_impl._M_finish > this->_M_impl._M_end_of_storage)
- __builtin_unreachable();
-
- size_t __sz = this->_M_impl._M_finish - this->_M_impl._M_start;
- size_t __cap = this->_M_impl._M_end_of_storage - this->_M_impl._M_start;
- if (__sz > __cap)
- __builtin_unreachable();
-#endif
- }
-
_GLIBCXX20_CONSTEXPR
void
_M_create_storage(size_t __n)
@@ -1005,10 +988,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
size_type
size() const _GLIBCXX_NOEXCEPT
- {
- _Base::_M_invariant();
- return size_type(this->_M_impl._M_finish - this->_M_impl._M_start);
- }
+ { return size_type(this->_M_impl._M_finish - this->_M_impl._M_start); }
/** Returns the size() of the largest possible %vector. */
_GLIBCXX_NODISCARD _GLIBCXX20_CONSTEXPR
@@ -1095,7 +1075,6 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
size_type
capacity() const _GLIBCXX_NOEXCEPT
{
- _Base::_M_invariant();
return size_type(this->_M_impl._M_end_of_storage
- this->_M_impl._M_start);
}
diff --git a/libstdc++-v3/include/bits/vector.tcc
b/libstdc++-v3/include/bits/vector.tcc
index d6fdea2dd01..acd11e2dc68 100644
--- a/libstdc++-v3/include/bits/vector.tcc
+++ b/libstdc++-v3/include/bits/vector.tcc
@@ -270,15 +270,18 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
vector<_Tp, _Alloc>::
_M_fill_assign(size_t __n, const value_type& __val)
{
+ const size_type __sz = size();
if (__n > capacity())
{
+ if (__n <= __sz)
+ __builtin_unreachable();
vector __tmp(__n, __val, _M_get_Tp_allocator());
__tmp._M_impl._M_swap_data(this->_M_impl);
}
- else if (__n > size())
+ else if (__n > __sz)
{
std::fill(begin(), end(), __val);
- const size_type __add = __n - size();
+ const size_type __add = __n - __sz;
_GLIBCXX_ASAN_ANNOTATE_GROW(__add);
this->_M_impl._M_finish =
std::__uninitialized_fill_n_a(this->_M_impl._M_finish,
@@ -316,10 +319,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
_M_assign_aux(_ForwardIterator __first, _ForwardIterator __last,
std::forward_iterator_tag)
{
+ const size_type __sz = size();
const size_type __len = std::distance(__first, __last);
if (__len > capacity())
{
+ if (__len <= __sz)
+ __builtin_unreachable();
+
_S_check_init_len(__len, _M_get_Tp_allocator());
pointer __tmp(_M_allocate_and_copy(__len, __first, __last));
std::_Destroy(this->_M_impl._M_start, this->_M_impl._M_finish,
@@ -332,14 +339,14 @@ _GLIBCXX_BEGIN_NAMESPACE_CONTAINER
this->_M_impl._M_finish = this->_M_impl._M_start + __len;
this->_M_impl._M_end_of_storage = this->_M_impl._M_finish;
}
- else if (size() >= __len)
+ else if (__sz >= __len)
_M_erase_at_end(std::copy(__first, __last, this->_M_impl._M_start));
else
{
_ForwardIterator __mid = __first;
- std::advance(__mid, size());
+ std::advance(__mid, __sz);
std::copy(__first, __mid, this->_M_impl._M_start);
- const size_type __attribute__((__unused__)) __n = __len - size();
+ const size_type __attribute__((__unused__)) __n = __len - __sz;
_GLIBCXX_ASAN_ANNOTATE_GROW(__n);
this->_M_impl._M_finish =
std::__uninitialized_copy_a(__mid, __last,
diff --git a/libstdc++-v3/testsuite/23_containers/vector/capacity/invariant.cc
b/libstdc++-v3/testsuite/23_containers/vector/modifiers/assign/no_realloc.cc
similarity index 70%
rename from libstdc++-v3/testsuite/23_containers/vector/capacity/invariant.cc
rename to
libstdc++-v3/testsuite/23_containers/vector/modifiers/assign/no_realloc.cc
index d68db694add..659f18dba56 100644
--- a/libstdc++-v3/testsuite/23_containers/vector/capacity/invariant.cc
+++ b/libstdc++-v3/testsuite/23_containers/vector/modifiers/assign/no_realloc.cc
@@ -1,5 +1,6 @@
// { dg-do compile }
// { dg-options "-O3 -g0" }
+// { dg-require-normal-mode "" }
// { dg-final { scan-assembler-not "_Znw" } }
// GCC should be able to optimize away the paths involving reallocation.
@@ -14,3 +15,8 @@ void fill_val(std::vector<int>& vec, int i)
{
vec.assign(vec.size(), i);
}
+
+void fill_range(std::vector<int>& vec, const int* first)
+{
+ vec.assign(first, first + vec.size());
+}
diff --git a/libstdc++-v3/testsuite/23_containers/vector/types/1.cc
b/libstdc++-v3/testsuite/23_containers/vector/types/1.cc
index 9be07d9fd5c..079e5af9556 100644
--- a/libstdc++-v3/testsuite/23_containers/vector/types/1.cc
+++ b/libstdc++-v3/testsuite/23_containers/vector/types/1.cc
@@ -18,7 +18,7 @@
// <http://www.gnu.org/licenses/>.
// { dg-do compile }
-// { dg-options "-Wno-unused-result -Wno-stringop-overread" }
+// { dg-options "-Wno-unused-result" }
#include <vector>
#include <testsuite_greedy_ops.h>
--
2.40.1
