Index: lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
===================================================================
--- lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
+++ lib/Target/Mips/MCTargetDesc/MipsMCAsmInfo.cpp
@@ -60,7 +60,9 @@
       TheTriple.getArch() == Triple::mipsel)
     UseIntegratedAssembler = true;
 
-  // Enable IAS by default for Debian mips64/mips64el.
-  if (TheTriple.getEnvironment() == Triple::GNUABI64)
+  // Enable IAS by default for Debian / FreeBSD / OpenBSD mips64/mips64el.
+  if (TheTriple.getEnvironment() == Triple::GNUABI64 ||
+      TheTriple.getOS() == Triple::FreeBSD ||
+      TheTriple.getOS() == Triple::OpenBSD)
     UseIntegratedAssembler = true;
 }