[PowerPC] fix potential verification errors on CFENCE8

This patch fixes a potential verification error (64-bit register operands for cmpw) with -verify-machineinstrs.

Differential Revision: https://reviews.llvm.org/D34208

llvm-svn: 305479
diff --git a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
index f3c68c4..236e513 100644
--- a/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
+++ b/llvm/lib/Target/PowerPC/PPCInstrInfo.cpp
@@ -1964,7 +1964,7 @@
   }
   case PPC::CFENCE8: {
     auto Val = MI.getOperand(0).getReg();
-    BuildMI(MBB, MI, DL, get(PPC::CMPW), PPC::CR7).addReg(Val).addReg(Val);
+    BuildMI(MBB, MI, DL, get(PPC::CMPD), PPC::CR7).addReg(Val).addReg(Val);
     BuildMI(MBB, MI, DL, get(PPC::CTRL_DEP))
         .addImm(PPC::PRED_NE_MINUS)
         .addReg(PPC::CR7)