Add an intrinsic and codegen support for fused multiply-accumulate. The intent
is to use this for architectures that have a native FMA instruction.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@134742 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
index 4b6d3ef..308150f 100644
--- a/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
+++ b/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp
@@ -3351,6 +3351,10 @@
     Results.push_back(ExpandFPLibCall(Node, RTLIB::REM_F32, RTLIB::REM_F64,
                                       RTLIB::REM_F80, RTLIB::REM_PPCF128));
     break;
+  case ISD::FMA:
+    Results.push_back(ExpandFPLibCall(Node, RTLIB::FMA_F32, RTLIB::FMA_F64,
+                                      RTLIB::FMA_F80, RTLIB::FMA_PPCF128));
+    break;
   case ISD::FP16_TO_FP32:
     Results.push_back(ExpandLibCall(RTLIB::FPEXT_F16_F32, Node, false));
     break;