[CodeGen] Add lround/llround builtins

This patch add the ISD::LROUND and ISD::LLROUND along with new
intrinsics.  The changes are straightforward as for other
floating-point rounding functions, with just some adjustments
required to handle the return value being an interger.

The idea is to optimize lround/llround generation for AArch64
in a subsequent patch.  Current semantic is just route it to libm
symbol.

llvm-svn: 360889

1 files changed, 16 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index 45a9a25..59fc075 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -6025,6 +6025,22 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
                              getValue(I.getArgOperand(0))));
     return nullptr;
   }
+  case Intrinsic::lround_i32:
+  case Intrinsic::lround_i64:
+  case Intrinsic::llround: {
+    unsigned Opcode;
+    MVT RetVT;
+    switch (Intrinsic) {
+    default: llvm_unreachable("Impossible intrinsic");  // Can't reach here.
+    case Intrinsic::lround_i32: Opcode = ISD::LROUND;  RetVT = MVT::i32; break;
+    case Intrinsic::lround_i64: Opcode = ISD::LROUND;  RetVT = MVT::i64; break;
+    case Intrinsic::llround:    Opcode = ISD::LLROUND; RetVT = MVT::i64; break;
+    }
+
+    setValue(&I, DAG.getNode(Opcode, sdl, RetVT,
+                             getValue(I.getArgOperand(0))));
+    return nullptr;
+  }
   case Intrinsic::minnum: {
     auto VT = getValue(I.getArgOperand(0)).getValueType();
     unsigned Opc =