[PATCH] D44823: [libcxx] Improving std::vector<char> and std::deque<char> perfomance

[Zhihao Yuan via Phabricator via cfe-commits]

lichray added inline comments.


================
Comment at: libcxx/trunk/include/__split_buffer:201
     __alloc_rr& __a = this->__alloc();
+    pointer __to_be_end = this->__end_;
     do
----------------
mclow.lists wrote:
> I have been asked specifically by the optimizer folks to NOT do things like this in libc++, but rather to file bugs against the optimizer.
> 
> And I have done so for this exact case:  https://bugs.llvm.org/show_bug.cgi?id=35637
>From the thread I didn't see that the compiler side asked you not to do so.

And I disagree with the view.  libc++ shouldn't *wait* for compilers, because we don't dictate users' compiler choices.  This change doesn't make libc++ worse to coming compilers, and makes libc++ better on existing compilers, so what benefit we get by not approving this?


Repository:
  rCXX libc++

https://reviews.llvm.org/D44823