Merging r339536:

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r339536 | ctopper | 2018-08-13 08:53:49 +0200 (Mon, 13 Aug 2018) | 3 lines

[SelectionDAG] In PromoteFloatOp_BITCAST, insert a bitcast after the fp_to_fp16 in case the result type isn't a scalar integer.

This is another variation of PR38533. In this case, the result type of the bitcast is legal and 16-bits wide, but not a scalar integer. So we need to emit the convert to i16 and then bitcast it to the true result type. This new bitcast will be further type legalized if necessary.
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llvm-svn: 339857

1 files changed, 11 insertions, 8 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index feca1c10f52..2e6f6edbce5 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -1778,15 +1778,16 @@ SDValue DAGTypeLegalizer::PromoteFloatOp_BITCAST(SDNode *N, unsigned OpNo) {
   SDValue Op = N->getOperand(0);
   EVT OpVT = Op->getValueType(0);
 
-  EVT IVT = EVT::getIntegerVT(*DAG.getContext(), OpVT.getSizeInBits());
-  assert (IVT == N->getValueType(0) && "Bitcast to type of different size");
-
   SDValue Promoted = GetPromotedFloat(N->getOperand(0));
   EVT PromotedVT = Promoted->getValueType(0);
 
   // Convert the promoted float value to the desired IVT.
-  return DAG.getNode(GetPromotionOpcode(PromotedVT, OpVT), SDLoc(N), IVT,
-                     Promoted);
+  EVT IVT = EVT::getIntegerVT(*DAG.getContext(), OpVT.getSizeInBits());
+  SDValue Convert = DAG.getNode(GetPromotionOpcode(PromotedVT, OpVT), SDLoc(N),
+                                IVT, Promoted);
+  // The final result type might not be an scalar so we need a bitcast. The
+  // bitcast will be further legalized if needed.
+  return DAG.getBitcast(N->getValueType(0), Convert);
 }
 
 // Promote Operand 1 of FCOPYSIGN.  Operand 0 ought to be handled by
@@ -1941,9 +1942,11 @@ void DAGTypeLegalizer::PromoteFloatResult(SDNode *N, unsigned ResNo) {
 SDValue DAGTypeLegalizer::PromoteFloatRes_BITCAST(SDNode *N) {
   EVT VT = N->getValueType(0);
   EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), VT);
-  // Input type isn't guaranteed to be i16 so bitcast if not. The bitcast
-  // will be legalized further if necessary.
-  SDValue Cast = DAG.getBitcast(MVT::i16, N->getOperand(0));
+  // Input type isn't guaranteed to be a scalar int so bitcast if not. The
+  // bitcast will be legalized further if necessary.
+  EVT IVT = EVT::getIntegerVT(*DAG.getContext(),
+                              N->getOperand(0).getValueType().getSizeInBits());
+  SDValue Cast = DAG.getBitcast(IVT, N->getOperand(0));
   return DAG.getNode(GetPromotionOpcode(VT, NVT), SDLoc(N), NVT, Cast);
 }