Index: lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
+++ lib/Target/Mips/MCTargetDesc/MipsTargetStreamer.cpp
@@ -482,6 +482,10 @@
   else
     EFlags |= ELF::EF_MIPS_ARCH_1;
 
+  // Machine
+  if (Features[Mips::FeatureCnMips])
+    EFlags |= ELF::EF_MIPS_MACH_OCTEON;
+
   // Other options.
   if (Features[Mips::FeatureNaN2008])
     EFlags |= ELF::EF_MIPS_NAN2008;
Index: test/MC/Mips/elf_eflags.s
===================================================================
--- test/MC/Mips/elf_eflags.s
+++ test/MC/Mips/elf_eflags.s
@@ -125,3 +125,6 @@
 
 # RUN: llvm-mc -filetype=obj -triple mips64el-unknown-linux -mcpu=mips64 -mattr=+nan2008 %s -o -| llvm-readobj -h | FileCheck --check-prefix=MIPS64EL-MIPS64-NAN2008 %s
 # MIPS64EL-MIPS64-NAN2008: Flags [ (0x60000406)
+
+# RUN: llvm-mc -filetype=obj -triple mipsel-unknown-linux -mcpu=octeon %s -o -| llvm-readobj -h | FileCheck --check-prefix=MIPSEL-OCTEON %s
+# MIPSEL-OCTEON: Flags [ (0x808B0006)