1 files changed, 108 insertions, 1 deletions

diff --git a/llvm/lib/Target/R600/SIISelLowering.cpp b/llvm/lib/Target/R600/SIISelLowering.cpp
index 911c5e55949..6d2e9575e59 100644
--- a/llvm/lib/Target/R600/SIISelLowering.cpp
+++ b/llvm/lib/Target/R600/SIISelLowering.cpp
@@ -235,6 +235,26 @@ SITargetLowering::SITargetLowering(TargetMachine &TM) :
 
   setTargetDAGCombine(ISD::UINT_TO_FP);
 
+  // All memory operations. Some folding on the pointer operand is done to help
+  // matching the constant offsets in the addressing modes.
+  setTargetDAGCombine(ISD::LOAD);
+  setTargetDAGCombine(ISD::STORE);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD);
+  setTargetDAGCombine(ISD::ATOMIC_STORE);
+  setTargetDAGCombine(ISD::ATOMIC_CMP_SWAP);
+  setTargetDAGCombine(ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS);
+  setTargetDAGCombine(ISD::ATOMIC_SWAP);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_ADD);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_SUB);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_AND);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_OR);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_XOR);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_NAND);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_MIN);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_MAX);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_UMIN);
+  setTargetDAGCombine(ISD::ATOMIC_LOAD_UMAX);
+
   setSchedulingPreference(Sched::RegPressure);
 }
 
@@ -1296,6 +1316,56 @@ SDValue SITargetLowering::performUCharToFloatCombine(SDNode *N,
   return SDValue();
 }
 
+// (shl (add x, c1), c2) -> add (shl x, c2), (shl c1, c2)
+
+// This is a variant of
+// (mul (add x, c1), c2) -> add (mul x, c2), (mul c1, c2),
+//
+// The normal DAG combiner will do this, but only if the add has one use since
+// that would increase the number of instructions.
+//
+// This prevents us from seeing a constant offset that can be folded into a
+// memory instruction's addressing mode. If we know the resulting add offset of
+// a pointer can be folded into an addressing offset, we can replace the pointer
+// operand with the add of new constant offset. This eliminates one of the uses,
+// and may allow the remaining use to also be simplified.
+//
+SDValue SITargetLowering::performSHLPtrCombine(SDNode *N,
+                                               unsigned AddrSpace,
+                                               DAGCombinerInfo &DCI) const {
+  SDValue N0 = N->getOperand(0);
+  SDValue N1 = N->getOperand(1);
+
+  if (N0.getOpcode() != ISD::ADD)
+    return SDValue();
+
+  const ConstantSDNode *CN1 = dyn_cast<ConstantSDNode>(N1);
+  if (!CN1)
+    return SDValue();
+
+  const ConstantSDNode *CAdd = dyn_cast<ConstantSDNode>(N0.getOperand(1));
+  if (!CAdd)
+    return SDValue();
+
+  const SIInstrInfo *TII = static_cast<const SIInstrInfo *>(
+      getTargetMachine().getSubtargetImpl()->getInstrInfo());
+
+  // If the resulting offset is too large, we can't fold it into the addressing
+  // mode offset.
+  APInt Offset = CAdd->getAPIntValue() << CN1->getAPIntValue();
+  if (!TII->canFoldOffset(Offset.getZExtValue(), AddrSpace))
+    return SDValue();
+
+  SelectionDAG &DAG = DCI.DAG;
+  SDLoc SL(N);
+  EVT VT = N->getValueType(0);
+
+  SDValue ShlX = DAG.getNode(ISD::SHL, SL, VT, N0.getOperand(0), N1);
+  SDValue COffset = DAG.getConstant(Offset, MVT::i32);
+
+  return DAG.getNode(ISD::ADD, SL, VT, ShlX, COffset);
+}
+
 SDValue SITargetLowering::PerformDAGCombine(SDNode *N,
                                             DAGCombinerInfo &DCI) const {
   SelectionDAG &DAG = DCI.DAG;
@@ -1348,8 +1418,45 @@ SDValue SITargetLowering::PerformDAGCombine(SDNode *N,
   case ISD::UINT_TO_FP: {
     return performUCharToFloatCombine(N, DCI);
   }
-  }
+  case ISD::LOAD:
+  case ISD::STORE:
+  case ISD::ATOMIC_LOAD:
+  case ISD::ATOMIC_STORE:
+  case ISD::ATOMIC_CMP_SWAP:
+  case ISD::ATOMIC_CMP_SWAP_WITH_SUCCESS:
+  case ISD::ATOMIC_SWAP:
+  case ISD::ATOMIC_LOAD_ADD:
+  case ISD::ATOMIC_LOAD_SUB:
+  case ISD::ATOMIC_LOAD_AND:
+  case ISD::ATOMIC_LOAD_OR:
+  case ISD::ATOMIC_LOAD_XOR:
+  case ISD::ATOMIC_LOAD_NAND:
+  case ISD::ATOMIC_LOAD_MIN:
+  case ISD::ATOMIC_LOAD_MAX:
+  case ISD::ATOMIC_LOAD_UMIN:
+  case ISD::ATOMIC_LOAD_UMAX: { // TODO: Target mem intrinsics.
+    if (DCI.isBeforeLegalize())
+      break;
+
+    MemSDNode *MemNode = cast<MemSDNode>(N);
+    SDValue Ptr = MemNode->getBasePtr();
 
+    // TODO: We could also do this for multiplies.
+    unsigned AS = MemNode->getAddressSpace();
+    if (Ptr.getOpcode() == ISD::SHL && AS != AMDGPUAS::PRIVATE_ADDRESS) {
+      SDValue NewPtr = performSHLPtrCombine(Ptr.getNode(), AS, DCI);
+      if (NewPtr) {
+        SmallVector<SDValue, 8> NewOps;
+        for (unsigned I = 0, N = MemNode->getNumOperands(); I != N; ++I)
+          NewOps.push_back(MemNode->getOperand(I));
+
+        NewOps[N->getOpcode() == ISD::STORE ? 2 : 1] = NewPtr;
+        return SDValue(DAG.UpdateNodeOperands(MemNode, NewOps), 0);
+      }
+    }
+    break;
+  }
+  }
   return AMDGPUTargetLowering::PerformDAGCombine(N, DCI);
 }