radeon/llvm: Handle selectcc DAG node

R600 can now select instructions from the selectcc DAG node, which is
typically lowered to one of the SET* instructions.

1 files changed, 141 insertions, 0 deletions

diff --git a/src/gallium/drivers/radeon/AMDGPUISelLowering.cpp b/src/gallium/drivers/radeon/AMDGPUISelLowering.cpp
index 8df80352085..a6827e5a24a 100644
--- a/src/gallium/drivers/radeon/AMDGPUISelLowering.cpp
+++ b/src/gallium/drivers/radeon/AMDGPUISelLowering.cpp
@@ -23,6 +23,9 @@ AMDGPUTargetLowering::AMDGPUTargetLowering(TargetMachine &TM) :
 {
   // We need to custom lower some of the intrinsics
   setOperationAction(ISD::INTRINSIC_WO_CHAIN, MVT::Other, Custom);
+
+  setOperationAction(ISD::SELECT_CC, MVT::f32, Custom);
+  setOperationAction(ISD::SELECT_CC, MVT::i32, Custom);
 }
 
 SDValue AMDGPUTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG)
@@ -31,6 +34,7 @@ SDValue AMDGPUTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG)
   switch (Op.getOpcode()) {
   default: return AMDILTargetLowering::LowerOperation(Op, DAG);
   case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
+  case ISD::SELECT_CC: return LowerSELECT_CC(Op, DAG);
   }
 }
 
@@ -101,6 +105,143 @@ SDValue AMDGPUTargetLowering::LowerIntrinsicLRP(SDValue Op,
                                                OneSubAC);
 }
 
+SDValue AMDGPUTargetLowering::LowerSELECT_CC(SDValue Op,
+    SelectionDAG &DAG) const
+{
+  DebugLoc DL = Op.getDebugLoc();
+  EVT VT = Op.getValueType();
+
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  SDValue True = Op.getOperand(2);
+  SDValue False = Op.getOperand(3);
+  SDValue CC = Op.getOperand(4);
+  ISD::CondCode CCOpcode = cast<CondCodeSDNode>(CC)->get();
+  SDValue Temp;
+
+ //cmovlog = src0 != 0.0f ? src1 : src2
+ //cmovlog = src0 == 0.0f ? src2 : src1
+ //cnde = src0 == 0.0f ? src1 : src2
+
+  // LHS and RHS are guaranteed to be the same value type
+  EVT CompareVT = LHS.getValueType();
+
+  // We need all the operands of SELECT_CC to have the same value type, so if
+  // necessary we need to convert LHS and RHS to be the same type True and
+  // False.  True and False are guaranteed to have the same type as this
+  // SELECT_CC node.
+
+  if (CompareVT !=  VT) {
+    ISD::NodeType ConversionOp = ISD::DELETED_NODE;
+    if (VT == MVT::f32 && CompareVT == MVT::i32) {
+      if (isUnsignedIntSetCC(CCOpcode)) {
+        ConversionOp = ISD::UINT_TO_FP;
+      } else {
+        ConversionOp = ISD::SINT_TO_FP;
+      }
+    } else if (VT == MVT::i32 && CompareVT == MVT::f32) {
+      ConversionOp = ISD::FP_TO_SINT;
+    } else {
+      // I don't think there will be any other type pairings.
+      assert(!"Unhandled operand type parings in SELECT_CC");
+    }
+    // XXX Check the value of LHS and RHS and avoid creating sequences like
+    // (FTOI (ITOF))
+    LHS = DAG.getNode(ConversionOp, DL, VT, LHS);
+    RHS = DAG.getNode(ConversionOp, DL, VT, RHS);
+  }
+
+  // If true is 1 and false is 0 or vice-versa we can handle this with a native
+  // instruction (SET* instructions).
+  if ((isOne(True) && isZero(False))) {
+    return DAG.getNode(ISD::SELECT_CC, DL, VT, LHS, RHS, True, False, CC);
+  }
+
+  // XXX If true is 0 and 1 is false, we can handle this with a native
+  // instruction, but we need to swap true and false and change the
+  // conditional.
+  if (isOne(False) && isZero(True)) {
+  }
+
+  // XXX Check if we can lower this to a SELECT or if it is supported by a native
+  // operation. (The code below does this but we don't have the Instruction
+  // selection patterns to do this yet.
+#if 0
+  if (isZero(LHS) || isZero(RHS)) {
+    SDValue Cond = (isZero(LHS) ? RHS : LHS);
+    bool SwapTF = false;
+    switch (CCOpcode) {
+    case ISD::SETOEQ:
+    case ISD::SETUEQ:
+    case ISD::SETEQ:
+      SwapTF = true;
+      // Fall through
+    case ISD::SETONE:
+    case ISD::SETUNE:
+    case ISD::SETNE:
+      // We can lower to select
+      if (SwapTF) {
+        Temp = True;
+        True = False;
+        False = Temp;
+      }
+      // CNDE
+      return DAG.getNode(ISD::SELECT, DL, VT, Cond, True, False);
+    default:
+      // Supported by a native operation (CNDGE, CNDGT)
+      return DAG.getNode(ISD::SELECT_CC, DL, VT, LHS, RHS, True, False, CC);
+    }
+  }
+#endif
+
+  // If we make it this for it means we have no native instructions to handle
+  // this SELECT_CC, so we must lower it.
+  SDValue One, Zero;
+
+  if (VT == MVT::f32) {
+    One = DAG.getConstantFP(1.0f, VT);
+    Zero = DAG.getConstantFP(0.0f, VT);
+  } else if (VT == MVT::i32) {
+    One = DAG.getConstant(1, VT);
+    Zero = DAG.getConstant(0, VT);
+  }
+  else {
+    assert(!"Unhandled value type in LowerSELECT_CC");
+  }
+
+  // Lower this unsupported SELECT_CC into a combination of two supported
+  // SELECT_CC operations.
+  SDValue Cond = DAG.getNode(ISD::SELECT_CC, DL, VT, LHS, RHS, One, Zero, CC);
+
+  return DAG.getNode(ISD::SELECT, DL, VT, Cond, True, False);
+}
+
+//===----------------------------------------------------------------------===//
+// Helper functions
+//===----------------------------------------------------------------------===//
+
+bool AMDGPUTargetLowering::isOne(SDValue Op) const
+{
+  if (ConstantFPSDNode * CFP = dyn_cast<ConstantFPSDNode>(Op)) {
+    return CFP->isExactlyValue(1.0);
+  }
+  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
+    return C->isOne();
+  }
+  return false;
+}
+
+bool AMDGPUTargetLowering::isZero(SDValue Op) const
+{
+  if (ConstantFPSDNode * CFP = dyn_cast<ConstantFPSDNode>(Op)) {
+    return CFP->getValueAPF().isZero();
+  }
+  if (ConstantSDNode *C = dyn_cast<ConstantSDNode>(Op)) {
+    return C->isNullValue();
+  }
+  return false;
+}
+
 void AMDGPUTargetLowering::addLiveIn(MachineInstr * MI,
     MachineFunction * MF, MachineRegisterInfo & MRI,
     const TargetInstrInfo * TII, unsigned reg) const