simple optimization: don't bother calling "exists" (which calls the syscall

"access").  Instead, just let the open call fail if the file doesn't exist.
This reduces the # syscalls executed.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@29173 91177308-0d34-0410-b5e6-96231b3b80d8

lib/System/Unix/MappedFile.inc

@@ -40,9 +40,6 @@ struct sys::MappedFileInfo {
 };
 
 void MappedFile::initialize() {
-  if (!path_.exists())
-    throw std::string("Can't open file: ") + path_.toString();
-  
   int mode = 0;
   if (options_ & READ_ACCESS) 
     if (options_ & WRITE_ACCESS)