Add ISD::FROUND for libm round()

All libm floating-point rounding functions, except for round(), had their own
ISD nodes. Recent PowerPC cores have an instruction for round(), and so here I'm
adding ISD::FROUND so that round() can be custom lowered as well.

For the most part, this is straightforward. I've added an intrinsic
and a matching ISD node just like those for nearbyint() and friends. The
SelectionDAG pattern I've named frnd (because ISD::FP_ROUND has already claimed
fround).

This will be used by the PowerPC backend in a follow-up commit.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@187926 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 9 insertions, 1 deletions

diff --git a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
index b9f4381b79..e23c5bea22 100644
--- a/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
+++ b/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp
@@ -4902,7 +4902,8 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
   case Intrinsic::ceil:
   case Intrinsic::trunc:
   case Intrinsic::rint:
-  case Intrinsic::nearbyint: {
+  case Intrinsic::nearbyint:
+  case Intrinsic::round: {
     unsigned Opcode;
     switch (Intrinsic) {
     default: llvm_unreachable("Impossible intrinsic");  // Can't reach here.
@@ -4915,6 +4916,7 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     case Intrinsic::trunc:     Opcode = ISD::FTRUNC;     break;
     case Intrinsic::rint:      Opcode = ISD::FRINT;      break;
     case Intrinsic::nearbyint: Opcode = ISD::FNEARBYINT; break;
+    case Intrinsic::round:     Opcode = ISD::FROUND;     break;
     }
 
     setValue(&I, DAG.getNode(Opcode, sdl,
@@ -5644,6 +5646,12 @@ void SelectionDAGBuilder::visitCall(const CallInst &I) {
         if (visitUnaryFloatCall(I, ISD::FRINT))
           return;
         break;
+      case LibFunc::round:
+      case LibFunc::roundf:
+      case LibFunc::roundl:
+        if (visitUnaryFloatCall(I, ISD::FROUND))
+          return;
+        break;
       case LibFunc::trunc:
       case LibFunc::truncf:
       case LibFunc::truncl: