Dave Zarzycki showed how the efficiency of shared_ptr could be significantly
increased. The following program is running 49% faster:
#include <iostream>
#include <memory>
#include <chrono>
#include <vector>
#include "chrono_io"
int main()
{
typedef std::chrono::high_resolution_clock Clock;
Clock::time_point t0 = Clock::now();
{
std::shared_ptr<int> p(new int (1));
std::vector<std::shared_ptr<int> > v(1000000, p);
v.insert(v.begin(), p);
v.insert(v.begin(), p);
v.insert(v.begin(), p);
v.insert(v.begin(), p);
}
Clock::time_point t1 = Clock::now();
std::cout << (t1-t0) << '\n';
}
llvm-svn: 119388
Cr-Mirrored-From: sso://chromium.googlesource.com/_direct/external/github.com/llvm/llvm-project
Cr-Mirrored-Commit: 9b35c8275c6e25442915a25648a1b0bade40a43e
diff --git a/src/memory.cpp b/src/memory.cpp
index 9918531..5bbf48e 100644
--- a/src/memory.cpp
+++ b/src/memory.cpp
@@ -50,11 +50,15 @@
increment(__shared_owners_);
}
-void
+bool
__shared_count::__release_shared()
{
if (decrement(__shared_owners_) == -1)
+ {
__on_zero_shared();
+ return true;
+ }
+ return false;
}
__shared_weak_count::~__shared_weak_count()
@@ -65,7 +69,6 @@
__shared_weak_count::__add_shared()
{
__shared_count::__add_shared();
- __add_weak();
}
void
@@ -77,8 +80,8 @@
void
__shared_weak_count::__release_shared()
{
- __shared_count::__release_shared();
- __release_weak();
+ if (__shared_count::__release_shared())
+ __release_weak();
}
void