Move the constant-folding support for FP_ROUND in SelectionDAG from the one-operand version of getNode() to the two-operand version, since it became a two-operand node at sound point.

Zap a testcase that this allows us to completely fold away.

llvm-svn: 154447

1 files changed, 10 insertions, 1 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
index 6e46d4989ad..92671d1678c 100644
--- a/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/SelectionDAG.cpp
@@ -2428,7 +2428,6 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL,
       case ISD::FABS:
         V.clearSign();
         return getConstantFP(V, VT);
-      case ISD::FP_ROUND:
       case ISD::FP_EXTEND: {
         bool ignored;
         // This can return overflow, underflow, or inexact; we don't care.
@@ -2994,6 +2993,16 @@ SDValue SelectionDAG::getNode(unsigned Opcode, DebugLoc DL, EVT VT,
       default: break;
       }
     }
+
+    if (Opcode == ISD::FP_ROUND) {
+      APFloat V = N1CFP->getValueAPF();    // make copy
+      bool ignored;
+      // This can return overflow, underflow, or inexact; we don't care.
+      // FIXME need to be more flexible about rounding mode.
+      (void)V.convert(*EVTToAPFloatSemantics(VT),
+                      APFloat::rmNearestTiesToEven, &ignored);
+      return getConstantFP(V, VT);
+    }
   }
 
   // Canonicalize an UNDEF to the RHS, even over a constant.