R600: Try to use lower types for 64bit division if possible

[oota-llvm.git] / lib / Target / R600 / AMDGPUISelLowering.cpp

diff --git a/lib/Target/R600/AMDGPUISelLowering.cpp b/lib/Target/R600/AMDGPUISelLowering.cpp
index 7ce0c36d74675686f698fb7e6240f4c70e673008..e169f9126242b5b9b24aa604c9612f535a47ec8f 100644 (file)
--- a/lib/Target/R600/AMDGPUISelLowering.cpp
+++ b/lib/Target/R600/AMDGPUISelLowering.cpp
@@ -1661,12 +1661,26 @@ void AMDGPUTargetLowering::LowerUDIVREM64(SDValue Op,
   SDValue RHS_Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, RHS, zero);
   SDValue RHS_Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, RHS, one);
 
+  if (VT == MVT::i64 &&
+    DAG.MaskedValueIsZero(RHS, APInt::getHighBitsSet(64, 32)) &&
+    DAG.MaskedValueIsZero(LHS, APInt::getHighBitsSet(64, 32))) {
+
+    SDValue Res = DAG.getNode(ISD::UDIVREM, DL, DAG.getVTList(HalfVT, HalfVT),
+                              LHS_Lo, RHS_Lo);
+
+    SDValue DIV = DAG.getNode(ISD::BUILD_PAIR, DL, VT, Res.getValue(0), zero);
+    SDValue REM = DAG.getNode(ISD::BUILD_PAIR, DL, VT, Res.getValue(1), zero);
+    Results.push_back(DIV);
+    Results.push_back(REM);
+    return;
+  }
+
   // Get Speculative values
   SDValue DIV_Part = DAG.getNode(ISD::UDIV, DL, HalfVT, LHS_Hi, RHS_Lo);
   SDValue REM_Part = DAG.getNode(ISD::UREM, DL, HalfVT, LHS_Hi, RHS_Lo);
 
-  SDValue REM_Hi = zero;
   SDValue REM_Lo = DAG.getSelectCC(DL, RHS_Hi, zero, REM_Part, LHS_Hi, ISD::SETEQ);
+  SDValue REM = DAG.getNode(ISD::BUILD_PAIR, DL, VT, REM_Lo, zero);
 
   SDValue DIV_Hi = DAG.getSelectCC(DL, RHS_Hi, zero, DIV_Part, zero, ISD::SETEQ);
   SDValue DIV_Lo = zero;
@@ -1674,8 +1688,10 @@ void AMDGPUTargetLowering::LowerUDIVREM64(SDValue Op,
   const unsigned halfBitWidth = HalfVT.getSizeInBits();
 
   for (unsigned i = 0; i < halfBitWidth; ++i) {
-    SDValue POS = DAG.getConstant(halfBitWidth - i - 1, HalfVT);
-    // Get Value of high bit
+    const unsigned bitPos = halfBitWidth - i - 1;
+    SDValue POS = DAG.getConstant(bitPos, HalfVT);
+    // Get value of high bit
+    // TODO: Remove the BFE part when the optimization is fixed
     SDValue HBit;
     if (halfBitWidth == 32 && Subtarget->hasBFE()) {
       HBit = DAG.getNode(AMDGPUISD::BFE_U32, DL, HalfVT, LHS_Lo, POS, one);
@@ -1683,33 +1699,23 @@ void AMDGPUTargetLowering::LowerUDIVREM64(SDValue Op,
       HBit = DAG.getNode(ISD::SRL, DL, HalfVT, LHS_Lo, POS);
       HBit = DAG.getNode(ISD::AND, DL, HalfVT, HBit, one);
     }
+    HBit = DAG.getNode(ISD::ZERO_EXTEND, DL, VT, HBit);
 
-    SDValue Carry = DAG.getNode(ISD::SRL, DL, HalfVT, REM_Lo,
-      DAG.getConstant(halfBitWidth - 1, HalfVT));
-    REM_Hi = DAG.getNode(ISD::SHL, DL, HalfVT, REM_Hi, one);
-    REM_Hi = DAG.getNode(ISD::OR, DL, HalfVT, REM_Hi, Carry);
+    // Shift
+    REM = DAG.getNode(ISD::SHL, DL, VT, REM, DAG.getConstant(1, VT));
+    // Add LHS high bit
+    REM = DAG.getNode(ISD::OR, DL, VT, REM, HBit);
 
-    REM_Lo = DAG.getNode(ISD::SHL, DL, HalfVT, REM_Lo, one);
-    REM_Lo = DAG.getNode(ISD::OR, DL, HalfVT, REM_Lo, HBit);
-
-
-    SDValue REM = DAG.getNode(ISD::BUILD_PAIR, DL, VT, REM_Lo, REM_Hi);
-
-    SDValue BIT = DAG.getConstant(1 << (halfBitWidth - i - 1), HalfVT);
+    SDValue BIT = DAG.getConstant(1 << bitPos, HalfVT);
     SDValue realBIT = DAG.getSelectCC(DL, REM, RHS, BIT, zero, ISD::SETUGE);
 
     DIV_Lo = DAG.getNode(ISD::OR, DL, HalfVT, DIV_Lo, realBIT);
 
     // Update REM
-
     SDValue REM_sub = DAG.getNode(ISD::SUB, DL, VT, REM, RHS);
-
     REM = DAG.getSelectCC(DL, REM, RHS, REM_sub, REM, ISD::SETUGE);
-    REM_Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, REM, zero);
-    REM_Hi = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, REM, one);
   }
 
-  SDValue REM = DAG.getNode(ISD::BUILD_PAIR, DL, VT, REM_Lo, REM_Hi);
   SDValue DIV = DAG.getNode(ISD::BUILD_PAIR, DL, VT, DIV_Lo, DIV_Hi);
   Results.push_back(DIV);
   Results.push_back(REM);
@@ -1730,8 +1736,8 @@ SDValue AMDGPUTargetLowering::LowerUDIVREM(SDValue Op,
   SDValue Den = Op.getOperand(1);
 
   if (VT == MVT::i32) {
-    if (DAG.MaskedValueIsZero(Op.getOperand(0), APInt(32, 0xff << 24)) &&
-        DAG.MaskedValueIsZero(Op.getOperand(1), APInt(32, 0xff << 24))) {
+    if (DAG.MaskedValueIsZero(Num, APInt::getHighBitsSet(32, 8)) &&
+        DAG.MaskedValueIsZero(Den, APInt::getHighBitsSet(32, 8))) {
       // TODO: We technically could do this for i64, but shouldn't that just be
       // handled by something generally reducing 64-bit division on 32-bit
       // values to 32-bit?
@@ -1843,19 +1849,31 @@ SDValue AMDGPUTargetLowering::LowerSDIVREM(SDValue Op,
   SDValue LHS = Op.getOperand(0);
   SDValue RHS = Op.getOperand(1);
 
-  if (VT == MVT::i32) {
-    if (DAG.ComputeNumSignBits(Op.getOperand(0)) > 8 &&
-        DAG.ComputeNumSignBits(Op.getOperand(1)) > 8) {
-      // TODO: We technically could do this for i64, but shouldn't that just be
-      // handled by something generally reducing 64-bit division on 32-bit
-      // values to 32-bit?
-      return LowerDIVREM24(Op, DAG, true);
-    }
-  }
-
   SDValue Zero = DAG.getConstant(0, VT);
   SDValue NegOne = DAG.getConstant(-1, VT);
 
+  if (VT == MVT::i32 &&
+      DAG.ComputeNumSignBits(LHS) > 8 &&
+      DAG.ComputeNumSignBits(RHS) > 8) {
+    return LowerDIVREM24(Op, DAG, true);
+  }
+  if (VT == MVT::i64 &&
+      DAG.ComputeNumSignBits(LHS) > 32 &&
+      DAG.ComputeNumSignBits(RHS) > 32) {
+    EVT HalfVT = VT.getHalfSizedIntegerVT(*DAG.getContext());
+
+    //HiLo split
+    SDValue LHS_Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, LHS, Zero);
+    SDValue RHS_Lo = DAG.getNode(ISD::EXTRACT_ELEMENT, DL, HalfVT, RHS, Zero);
+    SDValue DIVREM = DAG.getNode(ISD::SDIVREM, DL, DAG.getVTList(HalfVT, HalfVT),
+                                 LHS_Lo, RHS_Lo);
+    SDValue Res[2] = {
+      DAG.getNode(ISD::SIGN_EXTEND, DL, VT, DIVREM.getValue(0)),
+      DAG.getNode(ISD::SIGN_EXTEND, DL, VT, DIVREM.getValue(1))
+    };
+    return DAG.getMergeValues(Res, DL);
+  }
+
   SDValue LHSign = DAG.getSelectCC(DL, LHS, Zero, NegOne, Zero, ISD::SETLT);
   SDValue RHSign = DAG.getSelectCC(DL, RHS, Zero, NegOne, Zero, ISD::SETLT);
   SDValue DSign = DAG.getNode(ISD::XOR, DL, VT, LHSign, RHSign);