Simplify the raw_svector_ostream tweak from r212816

The memcpy() and overlap helps didn't help much with timings, so clean up the change.

The difference at this point is that we now leave growth of the storage buffer
up to SmallVector's implementation:

 -   OS.reserve(OS.capacity() * 2);
 +   OS.reserve(OS.size() + 64);

llvm-svn: 212837

1 files changed, 4 insertions, 13 deletions

diff --git a/llvm/lib/Support/raw_ostream.cpp b/llvm/lib/Support/raw_ostream.cpp
index b8a1537ae8a..d156826144a 100644
--- a/llvm/lib/Support/raw_ostream.cpp
+++ b/llvm/lib/Support/raw_ostream.cpp
@@ -729,26 +729,17 @@ void raw_svector_ostream::resync() {
 }
 
 void raw_svector_ostream::write_impl(const char *Ptr, size_t Size) {
-  size_t NewSize = OS.size() + Size;
-  size_t NewReservation = NewSize + 64;
-
-  bool NoOverlap = Ptr + Size < OS.begin() || Ptr > OS.begin() + OS.capacity();
-
-  if (NoOverlap) {
-    assert(!GetNumBytesInBuffer());
-    OS.reserve(NewReservation);
-    memcpy(OS.end(), Ptr, Size);
-    OS.set_size(NewSize);
-  } else if (Ptr == OS.end()) {
+  if (Ptr == OS.end()) {
     // Grow the buffer to include the scratch area without copying.
+    size_t NewSize = OS.size() + Size;
     assert(NewSize <= OS.capacity() && "Invalid write_impl() call!");
     OS.set_size(NewSize);
-    OS.reserve(NewReservation);
   } else {
+    assert(!GetNumBytesInBuffer());
     OS.append(Ptr, Ptr + Size);
-    OS.reserve(NewReservation);
   }
 
+  OS.reserve(OS.size() + 64);
   SetBuffer(OS.end(), OS.capacity() - OS.size());
 }