diff --git a/lib/Support/MemoryBuffer.cpp b/lib/Support/MemoryBuffer.cpp
index b0a20853b5c..0d5d4d7954f 100644
--- a/lib/Support/MemoryBuffer.cpp
+++ b/lib/Support/MemoryBuffer.cpp
@@ -322,9 +322,10 @@ error_code MemoryBuffer::getOpenFile(int FD, const char *Filename,
         return error_code(errno, posix_category());
       }
 
-      // If this is a named pipe or character device, we can't trust the size.
-      // Create the memory buffer by copying off the stream.
-      if (S_ISFIFO(FileInfo.st_mode) || S_ISCHR(FileInfo.st_mode)) {
+      // If this not a file or a block device (e.g. it's a named pipe
+      // or character device), we can't trust the size. Create the memory
+      // buffer by copying off the stream.
+      if (!S_ISREG(FileInfo.st_mode) && !S_ISBLK(FileInfo.st_mode)) {
         return getMemoryBufferForStream(FD, Filename, result);
       }