diff --git a/llvm/lib/Bytecode/Reader/Reader.cpp b/llvm/lib/Bytecode/Reader/Reader.cpp
index 9aa5455..23af02e 100644
--- a/llvm/lib/Bytecode/Reader/Reader.cpp
+++ b/llvm/lib/Bytecode/Reader/Reader.cpp
@@ -624,7 +624,7 @@
     size_t FileSize = 0;
     int BlockSize;
     uchar Buffer[4096], *FileData = 0;
-    while ((BlockSize = read(0, Buffer, 4))) {
+    while ((BlockSize = read(0, Buffer, 4096))) {
       if (BlockSize == -1) { free(FileData); return 0; }
 
       FileData = (uchar*)realloc(FileData, FileSize+BlockSize);