Fix a bug where DAGCombine was producing an illegal ConstantFP

node after legalize, and remove the workaround code from the
ARM backend.

llvm-svn: 78615

2 files changed, 12 insertions, 19 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
index 6119411d360..42d163f79b1 100644
--- a/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/DAGCombiner.cpp
@@ -3721,7 +3721,18 @@ SDValue DAGCombiner::visitBIT_CONVERT(SDNode *N) {
   // If the input is a constant, let getNode fold it.
   if (isa<ConstantSDNode>(N0) || isa<ConstantFPSDNode>(N0)) {
     SDValue Res = DAG.getNode(ISD::BIT_CONVERT, N->getDebugLoc(), VT, N0);
-    if (Res.getNode() != N) return Res;
+    if (Res.getNode() != N) {
+      if (!LegalOperations ||
+          TLI.isOperationLegal(Res.getNode()->getOpcode(), VT))
+        return Res;
+
+      // Folding it resulted in an illegal node, and it's too late to
+      // do that. Clean up the old node and forego the transformation.
+      // Ideally this won't happen very often, because instcombine
+      // and the earlier dagcombine runs (where illegal nodes are
+      // permitted) should have folded most of them already.
+      DAG.DeleteNode(Res.getNode());
+    }
   }
 
   // (conv (conv x, t1), t2) -> (conv x, t2)
diff --git a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 07575290c1d..1096e8eb01c 100644
--- a/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -988,24 +988,6 @@ SDNode *ARMDAGToDAGISel::Select(SDValue Op) {
     // Other cases are autogenerated.
     break;
   }
-  case ISD::ConstantFP: {
-    ConstantFPSDNode *CFP = cast<ConstantFPSDNode>(N);
-    EVT VT = CFP->getValueType(0);
-    ConstantFP *LLVMC = const_cast<ConstantFP*>(CFP->getConstantFPValue());
-    SDValue CPIdx = CurDAG->getTargetConstantPool(LLVMC, TLI.getPointerTy());
-    SDNode *ResNode;
-    SDValue Ops[] = {
-      CPIdx, 
-      CurDAG->getTargetConstant(0, EVT::i32),
-      getAL(CurDAG),
-      CurDAG->getRegister(0, EVT::i32),
-      CurDAG->getEntryNode()
-    };
-    unsigned Opc = (VT == EVT::f32) ? ARM::FLDS : ARM::FLDD;
-    ResNode=CurDAG->getTargetNode(Opc, dl, VT, EVT::Other, Ops, 5);
-    ReplaceUses(Op, SDValue(ResNode, 0));
-    return NULL;
-  }
   case ISD::FrameIndex: {
     // Selects to ADDri FI, 0 which in turn will become ADDri SP, imm.
     int FI = cast<FrameIndexSDNode>(N)->getIndex();