[AArch64] Fix DAG selection for cmps for fp16 type

Summary: When emitting comparison for fp16, in addition to promote the LHS and RHS to fp32, we need to change the VT as well.

Reviewers: t.p.northover

Subscribers: t.p.northover, aemerson, rengolin, llvm-commits

Differential Revision: http://reviews.llvm.org/D19922

llvm-svn: 269151
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index 8468a83..02db24e 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -1229,6 +1229,7 @@
     if (VT == MVT::f16) {
       LHS = DAG.getNode(ISD::FP_EXTEND, dl, MVT::f32, LHS);
       RHS = DAG.getNode(ISD::FP_EXTEND, dl, MVT::f32, RHS);
+      VT = MVT::f32;
     }
     return DAG.getNode(AArch64ISD::FCMP, dl, VT, LHS, RHS);
   }