Author: marshall
Date: Sat Jun 4 11:16:59 2016
New Revision: 271794
URL: http://llvm.org/viewvc/llvm-project?rev=271794&view=rev
Log:
Don't call memmove when there's nothing to move. Fixes PR#27978.
Modified:
libcxx/trunk/include/fstream
Modified: libcxx/trunk/include/fstream
URL:
http://llvm.org/viewvc/llvm-project/libcxx/trunk/include/fstream?rev=271794&r1=271793&r2=271794&view=diff
==============================================================================
--- libcxx/trunk/include/fstream (original)
+++ libcxx/trunk/include/fstream Sat Jun 4 11:16:59 2016
@@ -606,7 +606,9 @@ basic_filebuf<_CharT, _Traits>::underflo
}
else
{
- memmove(__extbuf_, __extbufnext_, __extbufend_ - __extbufnext_);
+ _LIBCPP_ASSERT ( !(__extbufnext_ == NULL && (__extbufend_ !=
__extbufnext_)), "underflow moving from NULL" );
+ if (__extbufend_ != __extbufnext_)
+ memmove(__extbuf_, __extbufnext_, __extbufend_ -
__extbufnext_);
__extbufnext_ = __extbuf_ + (__extbufend_ - __extbufnext_);
__extbufend_ = __extbuf_ + (__extbuf_ == __extbuf_min_ ?
sizeof(__extbuf_min_) : __ebs_);
size_t __nmemb = _VSTD::min(static_cast<size_t>(__ibs_ -
__unget_sz),
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