[Intrinsic] Signed Fixed Point Multiplication Intrinsic

Add an intrinsic that takes 2 signed integers with the scale of them provided
as the third argument and performs fixed point multiplication on them.

This is a part of implementing fixed point arithmetic in clang where some of
the more complex operations will be implemented as intrinsics.

Differential Revision: https://reviews.llvm.org/D54719

llvm-svn: 348912
diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
index bf81d0d..43df2ab 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGDumper.cpp
@@ -297,6 +297,7 @@
   case ISD::UADDSAT:                    return "uaddsat";
   case ISD::SSUBSAT:                    return "ssubsat";
   case ISD::USUBSAT:                    return "usubsat";
+  case ISD::SMULFIX:                    return "smulfix";
 
   // Conversion operators.
   case ISD::SIGN_EXTEND:                return "sign_extend";