[Power9] Add missing Power9 instructions.

The following 8 instructions are implemented in this patch.
addpcis(subpcis, lnia), darn, maddhd, maddhdu, maddld, setb

llvm-svn: 313636
diff --git a/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp b/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
index 52432a5..98be18b 100644
--- a/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
+++ b/llvm/lib/Target/PowerPC/AsmParser/PPCAsmParser.cpp
@@ -1138,6 +1138,15 @@
     Inst = TmpInst;
     break;
   }
+  case PPC::SUBPCIS: {
+    MCInst TmpInst;
+    int64_t N = Inst.getOperand(1).getImm();
+    TmpInst.setOpcode(PPC::ADDPCIS);
+    TmpInst.addOperand(Inst.getOperand(0));
+    TmpInst.addOperand(MCOperand::createImm(-N));
+    Inst = TmpInst;
+    break;
+  }
   case PPC::SRDI:
   case PPC::SRDIo: {
     MCInst TmpInst;