2 files changed, 49 insertions, 6 deletions

diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.cpp b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
index ab1cc7caaaa..1eabc0b7e45 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.cpp
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.cpp
@@ -852,12 +852,10 @@ SparcTargetLowering::LowerCall_32(TargetLowering::CallLoweringInfo &CLI,
       if (VA.getLocVT() == MVT::f64) {
         // Move from the float value from float registers into the
         // integer registers.
-
-        // TODO: The f64 -> v2i32 conversion is super-inefficient for
-        // constants: it sticks them in the constant pool, then loads
-        // to a fp register, then stores to temp memory, then loads to
-        // integer registers.
-        Arg = DAG.getNode(ISD::BITCAST, dl, MVT::v2i32, Arg);
+        if (ConstantFPSDNode *C = dyn_cast<ConstantFPSDNode>(Arg))
+          Arg = bitcastConstantFPToInt(C, dl, DAG);
+        else
+          Arg = DAG.getNode(ISD::BITCAST, dl, MVT::v2i32, Arg);
       }
 
       SDValue Part0 = DAG.getNode(ISD::EXTRACT_VECTOR_ELT, dl, MVT::i32,
@@ -1801,6 +1799,10 @@ SparcTargetLowering::SparcTargetLowering(const TargetMachine &TM,
     setOperationAction(ISD::FMUL, MVT::f32, Promote);
   }
 
+  // Custom combine bitcast between f64 and v2i32
+  if (!Subtarget->is64Bit())
+    setTargetDAGCombine(ISD::BITCAST);
+
   setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
 
   setMinFunctionAlignment(2);
@@ -3075,6 +3077,40 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   }
 }
 
+SDValue SparcTargetLowering::bitcastConstantFPToInt(ConstantFPSDNode *C,
+                                                    const SDLoc &DL,
+                                                    SelectionDAG &DAG) const {
+  APInt V = C->getValueAPF().bitcastToAPInt();
+  SDValue Lo = DAG.getConstant(V.zextOrTrunc(32), DL, MVT::i32);
+  SDValue Hi = DAG.getConstant(V.lshr(32).zextOrTrunc(32), DL, MVT::i32);
+  if (DAG.getDataLayout().isLittleEndian())
+    std::swap(Lo, Hi);
+  return DAG.getBuildVector(MVT::v2i32, DL, {Hi, Lo});
+}
+
+SDValue SparcTargetLowering::PerformBITCASTCombine(SDNode *N,
+                                                   DAGCombinerInfo &DCI) const {
+  SDLoc dl(N);
+  SDValue Src = N->getOperand(0);
+
+  if (isa<ConstantFPSDNode>(Src) && N->getSimpleValueType(0) == MVT::v2i32 &&
+      Src.getSimpleValueType() == MVT::f64)
+    return bitcastConstantFPToInt(cast<ConstantFPSDNode>(Src), dl, DCI.DAG);
+
+  return SDValue();
+}
+
+SDValue SparcTargetLowering::PerformDAGCombine(SDNode *N,
+                                               DAGCombinerInfo &DCI) const {
+  switch (N->getOpcode()) {
+  default:
+    break;
+  case ISD::BITCAST:
+    return PerformBITCASTCombine(N, DCI);
+  }
+  return SDValue();
+}
+
 MachineBasicBlock *
 SparcTargetLowering::EmitInstrWithCustomInserter(MachineInstr &MI,
                                                  MachineBasicBlock *BB) const {
diff --git a/llvm/lib/Target/Sparc/SparcISelLowering.h b/llvm/lib/Target/Sparc/SparcISelLowering.h
index 9741674cbfe..0f7c7311616 100644
--- a/llvm/lib/Target/Sparc/SparcISelLowering.h
+++ b/llvm/lib/Target/Sparc/SparcISelLowering.h
@@ -191,6 +191,13 @@ namespace llvm {
 
     SDValue LowerINTRINSIC_WO_CHAIN(SDValue Op, SelectionDAG &DAG) const;
 
+    SDValue PerformBITCASTCombine(SDNode *N, DAGCombinerInfo &DCI) const;
+
+    SDValue bitcastConstantFPToInt(ConstantFPSDNode *C, const SDLoc &DL,
+                                   SelectionDAG &DAG) const;
+
+    SDValue PerformDAGCombine(SDNode *N, DAGCombinerInfo &DCI) const override;
+
     bool ShouldShrinkFPConstant(EVT VT) const override {
       // Do not shrink FP constpool if VT == MVT::f128.
       // (ldd, call _Q_fdtoq) is more expensive than two ldds.