[LegalizeTypes][RISCV] Soften FCOPYSIGN operand

Summary: Adds support for softening FCOPYSIGN operands.
Adds RISC-V tests that exercise the new softening code.

Reviewers: asb, lenary, efriedma
Reviewed By: efriedma
Tags: #llvm
Differential Revision: https://reviews.llvm.org/D70679

2 files changed, 36 insertions, 0 deletions

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
index c4a74d5c1c7..8dbff7d2735 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeFloatTypes.cpp
@@ -854,6 +854,7 @@ bool DAGTypeLegalizer::SoftenFloatOperand(SDNode *N, unsigned OpNo) {
   case ISD::SELECT_CC:   Res = SoftenFloatOp_SELECT_CC(N); break;
   case ISD::SETCC:       Res = SoftenFloatOp_SETCC(N); break;
   case ISD::STORE:       Res = SoftenFloatOp_STORE(N, OpNo); break;
+  case ISD::FCOPYSIGN:   Res = SoftenFloatOp_FCOPYSIGN(N); break;
   }
 
   // If the result is null, the sub-method took care of registering results etc.
@@ -1036,6 +1037,40 @@ SDValue DAGTypeLegalizer::SoftenFloatOp_STORE(SDNode *N, unsigned OpNo) {
                       ST->getMemOperand());
 }
 
+SDValue DAGTypeLegalizer::SoftenFloatOp_FCOPYSIGN(SDNode *N) {
+  SDValue LHS = N->getOperand(0);
+  SDValue RHS = BitConvertToInteger(N->getOperand(1));
+  SDLoc dl(N);
+
+  EVT LVT = LHS.getValueType();
+  EVT ILVT = EVT::getIntegerVT(*DAG.getContext(), LVT.getSizeInBits());
+  EVT RVT = RHS.getValueType();
+
+  unsigned LSize = LVT.getSizeInBits();
+  unsigned RSize = RVT.getSizeInBits();
+
+  // Shift right or sign-extend it if the two operands have different types.
+  int SizeDiff = RSize - LSize;
+  if (SizeDiff > 0) {
+    RHS =
+        DAG.getNode(ISD::SRL, dl, RVT, RHS,
+                    DAG.getConstant(SizeDiff, dl,
+                                    TLI.getShiftAmountTy(RHS.getValueType(),
+                                                         DAG.getDataLayout())));
+    RHS = DAG.getNode(ISD::TRUNCATE, dl, ILVT, RHS);
+  } else if (SizeDiff < 0) {
+    RHS = DAG.getNode(ISD::ANY_EXTEND, dl, LVT, RHS);
+    RHS =
+        DAG.getNode(ISD::SHL, dl, ILVT, RHS,
+                    DAG.getConstant(-SizeDiff, dl,
+                                    TLI.getShiftAmountTy(RHS.getValueType(),
+                                                         DAG.getDataLayout())));
+  }
+
+  RHS = DAG.getBitcast(LVT, RHS);
+  return DAG.getNode(ISD::FCOPYSIGN, dl, LVT, LHS, RHS);
+}
+
 SDValue DAGTypeLegalizer::SoftenFloatOp_LROUND(SDNode *N) {
   EVT NVT = TLI.getTypeToTransformTo(*DAG.getContext(), N->getValueType(0));
 
diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
index c944bda3700..89410ccd857 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeTypes.h
@@ -540,6 +540,7 @@ private:
   SDValue SoftenFloatOp_SELECT_CC(SDNode *N);
   SDValue SoftenFloatOp_SETCC(SDNode *N);
   SDValue SoftenFloatOp_STORE(SDNode *N, unsigned OpNo);
+  SDValue SoftenFloatOp_FCOPYSIGN(SDNode *N);
 
   //===--------------------------------------------------------------------===//
   // Float Expansion Support: LegalizeFloatTypes.cpp