diff --git a/llvm/lib/Target/Mips/MipsSubtarget.cpp b/llvm/lib/Target/Mips/MipsSubtarget.cpp
index cd462c7..f6af7e2 100644
--- a/llvm/lib/Target/Mips/MipsSubtarget.cpp
+++ b/llvm/lib/Target/Mips/MipsSubtarget.cpp
@@ -104,6 +104,9 @@
   if (IsFPXX && (isABI_N32() || isABI_N64()))
     report_fatal_error("FPXX is not permitted for the N32/N64 ABI's.", false);
 
+  if (hasMips64r6() && InMicroMipsMode)
+    report_fatal_error("microMIPS64R6 is not supported", false);
+
   if (hasMips32r6()) {
     StringRef ISA = hasMips64r6() ? "MIPS64r6" : "MIPS32r6";