R600: Move division custom lowering out of AMDILISelLowering

llvm-svn: 210997
diff --git a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
index d4fd316..3716602 100644
--- a/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
+++ b/llvm/lib/Target/R600/AMDGPUISelLowering.cpp
@@ -464,8 +464,6 @@
                      "instruction is not implemented yet!");
     break;
   // AMDIL DAG lowering
-  case ISD::SDIV: return LowerSDIV(Op, DAG);
-  case ISD::SREM: return LowerSREM(Op, DAG);
   case ISD::SIGN_EXTEND_INREG: return LowerSIGN_EXTEND_INREG(Op, DAG);
   case ISD::BRCOND: return LowerBRCOND(Op, DAG);
   // AMDGPU DAG lowering
@@ -473,6 +471,8 @@
   case ISD::EXTRACT_SUBVECTOR: return LowerEXTRACT_SUBVECTOR(Op, DAG);
   case ISD::FrameIndex: return LowerFrameIndex(Op, DAG);
   case ISD::INTRINSIC_WO_CHAIN: return LowerINTRINSIC_WO_CHAIN(Op, DAG);
+  case ISD::SDIV: return LowerSDIV(Op, DAG);
+  case ISD::SREM: return LowerSREM(Op, DAG);
   case ISD::UDIVREM: return LowerUDIVREM(Op, DAG);
   case ISD::UINT_TO_FP: return LowerUINT_TO_FP(Op, DAG);
   }
@@ -1199,6 +1199,250 @@
   return SDValue();
 }
 
+SDValue AMDGPUTargetLowering::LowerSDIV24(SDValue Op, SelectionDAG &DAG) const {
+  SDLoc DL(Op);
+  EVT OVT = Op.getValueType();
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  MVT INTTY;
+  MVT FLTTY;
+  if (!OVT.isVector()) {
+    INTTY = MVT::i32;
+    FLTTY = MVT::f32;
+  } else if (OVT.getVectorNumElements() == 2) {
+    INTTY = MVT::v2i32;
+    FLTTY = MVT::v2f32;
+  } else if (OVT.getVectorNumElements() == 4) {
+    INTTY = MVT::v4i32;
+    FLTTY = MVT::v4f32;
+  }
+  unsigned bitsize = OVT.getScalarType().getSizeInBits();
+  // char|short jq = ia ^ ib;
+  SDValue jq = DAG.getNode(ISD::XOR, DL, OVT, LHS, RHS);
+
+  // jq = jq >> (bitsize - 2)
+  jq = DAG.getNode(ISD::SRA, DL, OVT, jq, DAG.getConstant(bitsize - 2, OVT));
+
+  // jq = jq | 0x1
+  jq = DAG.getNode(ISD::OR, DL, OVT, jq, DAG.getConstant(1, OVT));
+
+  // jq = (int)jq
+  jq = DAG.getSExtOrTrunc(jq, DL, INTTY);
+
+  // int ia = (int)LHS;
+  SDValue ia = DAG.getSExtOrTrunc(LHS, DL, INTTY);
+
+  // int ib, (int)RHS;
+  SDValue ib = DAG.getSExtOrTrunc(RHS, DL, INTTY);
+
+  // float fa = (float)ia;
+  SDValue fa = DAG.getNode(ISD::SINT_TO_FP, DL, FLTTY, ia);
+
+  // float fb = (float)ib;
+  SDValue fb = DAG.getNode(ISD::SINT_TO_FP, DL, FLTTY, ib);
+
+  // float fq = native_divide(fa, fb);
+  SDValue fq = DAG.getNode(AMDGPUISD::DIV_INF, DL, FLTTY, fa, fb);
+
+  // fq = trunc(fq);
+  fq = DAG.getNode(ISD::FTRUNC, DL, FLTTY, fq);
+
+  // float fqneg = -fq;
+  SDValue fqneg = DAG.getNode(ISD::FNEG, DL, FLTTY, fq);
+
+  // float fr = mad(fqneg, fb, fa);
+  SDValue fr = DAG.getNode(ISD::FADD, DL, FLTTY,
+      DAG.getNode(ISD::MUL, DL, FLTTY, fqneg, fb), fa);
+
+  // int iq = (int)fq;
+  SDValue iq = DAG.getNode(ISD::FP_TO_SINT, DL, INTTY, fq);
+
+  // fr = fabs(fr);
+  fr = DAG.getNode(ISD::FABS, DL, FLTTY, fr);
+
+  // fb = fabs(fb);
+  fb = DAG.getNode(ISD::FABS, DL, FLTTY, fb);
+
+  // int cv = fr >= fb;
+  SDValue cv;
+  if (INTTY == MVT::i32) {
+    cv = DAG.getSetCC(DL, INTTY, fr, fb, ISD::SETOGE);
+  } else {
+    cv = DAG.getSetCC(DL, INTTY, fr, fb, ISD::SETOGE);
+  }
+  // jq = (cv ? jq : 0);
+  jq = DAG.getNode(ISD::SELECT, DL, OVT, cv, jq,
+      DAG.getConstant(0, OVT));
+  // dst = iq + jq;
+  iq = DAG.getSExtOrTrunc(iq, DL, OVT);
+  iq = DAG.getNode(ISD::ADD, DL, OVT, iq, jq);
+  return iq;
+}
+
+SDValue AMDGPUTargetLowering::LowerSDIV32(SDValue Op, SelectionDAG &DAG) const {
+  SDLoc DL(Op);
+  EVT OVT = Op.getValueType();
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  // The LowerSDIV32 function generates equivalent to the following IL.
+  // mov r0, LHS
+  // mov r1, RHS
+  // ilt r10, r0, 0
+  // ilt r11, r1, 0
+  // iadd r0, r0, r10
+  // iadd r1, r1, r11
+  // ixor r0, r0, r10
+  // ixor r1, r1, r11
+  // udiv r0, r0, r1
+  // ixor r10, r10, r11
+  // iadd r0, r0, r10
+  // ixor DST, r0, r10
+
+  // mov r0, LHS
+  SDValue r0 = LHS;
+
+  // mov r1, RHS
+  SDValue r1 = RHS;
+
+  // ilt r10, r0, 0
+  SDValue r10 = DAG.getSelectCC(DL,
+      r0, DAG.getConstant(0, OVT),
+      DAG.getConstant(-1, MVT::i32),
+      DAG.getConstant(0, MVT::i32),
+      ISD::SETLT);
+
+  // ilt r11, r1, 0
+  SDValue r11 = DAG.getSelectCC(DL,
+      r1, DAG.getConstant(0, OVT),
+      DAG.getConstant(-1, MVT::i32),
+      DAG.getConstant(0, MVT::i32),
+      ISD::SETLT);
+
+  // iadd r0, r0, r10
+  r0 = DAG.getNode(ISD::ADD, DL, OVT, r0, r10);
+
+  // iadd r1, r1, r11
+  r1 = DAG.getNode(ISD::ADD, DL, OVT, r1, r11);
+
+  // ixor r0, r0, r10
+  r0 = DAG.getNode(ISD::XOR, DL, OVT, r0, r10);
+
+  // ixor r1, r1, r11
+  r1 = DAG.getNode(ISD::XOR, DL, OVT, r1, r11);
+
+  // udiv r0, r0, r1
+  r0 = DAG.getNode(ISD::UDIV, DL, OVT, r0, r1);
+
+  // ixor r10, r10, r11
+  r10 = DAG.getNode(ISD::XOR, DL, OVT, r10, r11);
+
+  // iadd r0, r0, r10
+  r0 = DAG.getNode(ISD::ADD, DL, OVT, r0, r10);
+
+  // ixor DST, r0, r10
+  SDValue DST = DAG.getNode(ISD::XOR, DL, OVT, r0, r10);
+  return DST;
+}
+
+SDValue AMDGPUTargetLowering::LowerSDIV64(SDValue Op, SelectionDAG &DAG) const {
+  return SDValue(Op.getNode(), 0);
+}
+
+SDValue AMDGPUTargetLowering::LowerSDIV(SDValue Op, SelectionDAG &DAG) const {
+  EVT OVT = Op.getValueType().getScalarType();
+
+  if (OVT == MVT::i64)
+    return LowerSDIV64(Op, DAG);
+
+  if (OVT.getScalarType() == MVT::i32)
+    return LowerSDIV32(Op, DAG);
+
+  if (OVT == MVT::i16 || OVT == MVT::i8) {
+    // FIXME: We should be checking for the masked bits. This isn't reached
+    // because i8 and i16 are not legal types.
+    return LowerSDIV24(Op, DAG);
+  }
+
+  return SDValue(Op.getNode(), 0);
+}
+
+SDValue AMDGPUTargetLowering::LowerSREM32(SDValue Op, SelectionDAG &DAG) const {
+  SDLoc DL(Op);
+  EVT OVT = Op.getValueType();
+  SDValue LHS = Op.getOperand(0);
+  SDValue RHS = Op.getOperand(1);
+  // The LowerSREM32 function generates equivalent to the following IL.
+  // mov r0, LHS
+  // mov r1, RHS
+  // ilt r10, r0, 0
+  // ilt r11, r1, 0
+  // iadd r0, r0, r10
+  // iadd r1, r1, r11
+  // ixor r0, r0, r10
+  // ixor r1, r1, r11
+  // udiv r20, r0, r1
+  // umul r20, r20, r1
+  // sub r0, r0, r20
+  // iadd r0, r0, r10
+  // ixor DST, r0, r10
+
+  // mov r0, LHS
+  SDValue r0 = LHS;
+
+  // mov r1, RHS
+  SDValue r1 = RHS;
+
+  // ilt r10, r0, 0
+  SDValue r10 = DAG.getSetCC(DL, OVT, r0, DAG.getConstant(0, OVT), ISD::SETLT);
+
+  // ilt r11, r1, 0
+  SDValue r11 = DAG.getSetCC(DL, OVT, r1, DAG.getConstant(0, OVT), ISD::SETLT);
+
+  // iadd r0, r0, r10
+  r0 = DAG.getNode(ISD::ADD, DL, OVT, r0, r10);
+
+  // iadd r1, r1, r11
+  r1 = DAG.getNode(ISD::ADD, DL, OVT, r1, r11);
+
+  // ixor r0, r0, r10
+  r0 = DAG.getNode(ISD::XOR, DL, OVT, r0, r10);
+
+  // ixor r1, r1, r11
+  r1 = DAG.getNode(ISD::XOR, DL, OVT, r1, r11);
+
+  // udiv r20, r0, r1
+  SDValue r20 = DAG.getNode(ISD::UREM, DL, OVT, r0, r1);
+
+  // umul r20, r20, r1
+  r20 = DAG.getNode(AMDGPUISD::UMUL, DL, OVT, r20, r1);
+
+  // sub r0, r0, r20
+  r0 = DAG.getNode(ISD::SUB, DL, OVT, r0, r20);
+
+  // iadd r0, r0, r10
+  r0 = DAG.getNode(ISD::ADD, DL, OVT, r0, r10);
+
+  // ixor DST, r0, r10
+  SDValue DST = DAG.getNode(ISD::XOR, DL, OVT, r0, r10);
+  return DST;
+}
+
+SDValue AMDGPUTargetLowering::LowerSREM64(SDValue Op, SelectionDAG &DAG) const {
+  return SDValue(Op.getNode(), 0);
+}
+
+SDValue AMDGPUTargetLowering::LowerSREM(SDValue Op, SelectionDAG &DAG) const {
+  EVT OVT = Op.getValueType();
+
+  if (OVT.getScalarType() == MVT::i64)
+    return LowerSREM64(Op, DAG);
+
+  if (OVT.getScalarType() == MVT::i32)
+    return LowerSREM32(Op, DAG);
+
+  return SDValue(Op.getNode(), 0);
+}
+
 SDValue AMDGPUTargetLowering::LowerUDIVREM(SDValue Op,
                                            SelectionDAG &DAG) const {
   SDLoc DL(Op);