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.

llvm-svn: 187926

1 files changed, 5 insertions, 0 deletions

diff --git a/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp b/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp
index 4e30c537..05dad8a 100644
--- a/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp
+++ b/llvm/lib/Target/PowerPC/PPCCTRLoops.cpp
@@ -259,6 +259,7 @@ bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) {
           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;
           }
         }
 
@@ -309,6 +310,10 @@ bool PPCCTRLoops::mightUseCTR(const Triple &TT, BasicBlock *BB) {
           case LibFunc::rintf:
           case LibFunc::rintl:
             Opcode = ISD::FRINT; break;
+          case LibFunc::round:
+          case LibFunc::roundf:
+          case LibFunc::roundl:
+            Opcode = ISD::FROUND; break;
           case LibFunc::trunc:
           case LibFunc::truncf:
           case LibFunc::truncl: