Add __builtin_readcyclecounter() to produce the @llvm.readcyclecounter() intrinsic.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161310 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGBuiltin.cpp b/lib/CodeGen/CGBuiltin.cpp
index e47a9a3..65c782e 100644
--- a/lib/CodeGen/CGBuiltin.cpp
+++ b/lib/CodeGen/CGBuiltin.cpp
@@ -365,6 +365,10 @@
     Value *F = CGM.getIntrinsic(Intrinsic::prefetch);
     return RValue::get(Builder.CreateCall4(F, Address, RW, Locality, Data));
   }
+  case Builtin::BI__builtin_readcyclecounter: {
+    Value *F = CGM.getIntrinsic(Intrinsic::readcyclecounter);
+    return RValue::get(Builder.CreateCall(F));
+  }
   case Builtin::BI__builtin_trap: {
     Value *F = CGM.getIntrinsic(Intrinsic::trap);
     return RValue::get(Builder.CreateCall(F));