Read 64 bits at a time in the bitcode reader.

The reading of 64 bit values could still be optimized, but at least this cuts
down on the number of virtual calls to fetch more data.

llvm-svn: 221865

1 files changed, 3 insertions, 4 deletions

diff --git a/llvm/lib/Support/StreamingMemoryObject.cpp b/llvm/lib/Support/StreamingMemoryObject.cpp
index b3723d03981..f0eb83153e0 100644
--- a/llvm/lib/Support/StreamingMemoryObject.cpp
+++ b/llvm/lib/Support/StreamingMemoryObject.cpp
@@ -90,13 +90,12 @@ uint64_t StreamingMemoryObject::getExtent() const {
 uint64_t StreamingMemoryObject::readBytes(uint8_t *Buf, uint64_t Size,
                                           uint64_t Address) const {
   fetchToPos(Address + Size - 1);
-  uint64_t BufferSize = Bytes.size() - BytesSkipped;
-  if (Address >= BufferSize)
+  if (Address >= BytesRead)
     return 0;
 
   uint64_t End = Address + Size;
-  if (End > BufferSize)
-    End = BufferSize;
+  if (End > BytesRead)
+    End = BytesRead;
   Size = End - Address;
   assert(Size >= 0);
   memcpy(Buf, &Bytes[Address + BytesSkipped], Size);