diff --git a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
index 13250b3..aa819ee 100644
--- a/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
+++ b/llvm/lib/Target/PowerPC/PPCISelLowering.cpp
@@ -394,8 +394,10 @@
     setOperationAction(ISD::BUILD_VECTOR, MVT::v4f32, Custom);
   }
 
-  if (Subtarget->has64BitSupport())
+  if (Subtarget->has64BitSupport()) {
     setOperationAction(ISD::PREFETCH, MVT::Other, Legal);
+    setOperationAction(ISD::READCYCLECOUNTER, MVT::i64, Legal);
+  }
 
   setOperationAction(ISD::ATOMIC_LOAD,  MVT::i32, Expand);
   setOperationAction(ISD::ATOMIC_STORE, MVT::i32, Expand);
diff --git a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
index 91c5366..92a5051 100644
--- a/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
+++ b/llvm/lib/Target/PowerPC/PPCInstr64Bit.td
@@ -265,6 +265,11 @@
              PPC970_DGroup_First, PPC970_Unit_FXU;
 }
 
+let Pattern = [(set G8RC:$rT, readcyclecounter)] in
+def MFTB8 : XFXForm_1_ext<31, 371, 268, (outs G8RC:$rT), (ins),
+                          "mftb $rT", SprMFTB>,
+            PPC970_DGroup_First, PPC970_Unit_FXU;
+
 let Defs = [X1], Uses = [X1] in
 def DYNALLOC8 : Pseudo<(outs G8RC:$result), (ins G8RC:$negsize, memri:$fpsi),"",
                        [(set G8RC:$result,