[mips] Custom-legalize BR_JT.

In N64-static, GOT address is needed to compute the branch address.



git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@176580 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Target/Mips/MipsISelLowering.cpp

@@ -331,6 +331,7 @@ MipsTargetLowering(MipsTargetMachine &TM)
   AddPromotedToType(ISD::SETCC, MVT::i1, MVT::i32);
 
   // Mips Custom Operations
+  setOperationAction(ISD::BR_JT,              MVT::Other, Custom);
   setOperationAction(ISD::GlobalAddress,      MVT::i32,   Custom);
   setOperationAction(ISD::BlockAddress,       MVT::i32,   Custom);
   setOperationAction(ISD::GlobalTLSAddress,   MVT::i32,   Custom);
@@ -396,7 +397,6 @@ MipsTargetLowering(MipsTargetMachine &TM)
   setOperationAction(ISD::UREM, MVT::i64, Expand);
 
   // Operations not directly supported by Mips.
-  setOperationAction(ISD::BR_JT,             MVT::Other, Expand);
   setOperationAction(ISD::BR_CC,             MVT::Other, Expand);
   setOperationAction(ISD::SELECT_CC,         MVT::Other, Expand);
   setOperationAction(ISD::UINT_TO_FP,        MVT::i32,   Expand);
@@ -1039,6 +1039,7 @@ LowerOperation(SDValue Op, SelectionDAG &DAG) const
 {
   switch (Op.getOpcode())
   {
+    case ISD::BR_JT:              return LowerBR_JT(Op, DAG);
     case ISD::BRCOND:             return LowerBRCOND(Op, DAG);
     case ISD::ConstantPool:       return LowerConstantPool(Op, DAG);
     case ISD::GlobalAddress:      return LowerGlobalAddress(Op, DAG);
@@ -2166,6 +2167,36 @@ MipsTargetLowering::EmitAtomicCmpSwapPartword(MachineInstr *MI,
 //===----------------------------------------------------------------------===//
 //  Misc Lower Operation implementation
 //===----------------------------------------------------------------------===//
+SDValue MipsTargetLowering::LowerBR_JT(SDValue Op, SelectionDAG &DAG) const {
+  SDValue Chain = Op.getOperand(0);
+  SDValue Table = Op.getOperand(1);
+  SDValue Index = Op.getOperand(2);
+  DebugLoc DL = Op.getDebugLoc();
+  EVT PTy = getPointerTy();
+  unsigned EntrySize =
+    DAG.getMachineFunction().getJumpTableInfo()->getEntrySize(*getDataLayout());
+
+  Index = DAG.getNode(ISD::MUL, DL, PTy, Index,
+                      DAG.getConstant(EntrySize, PTy));
+  SDValue Addr = DAG.getNode(ISD::ADD, DL, PTy, Index, Table);
+
+  EVT MemVT = EVT::getIntegerVT(*DAG.getContext(), EntrySize * 8);
+  Addr = DAG.getExtLoad(ISD::SEXTLOAD, DL, PTy, Chain, Addr,
+                        MachinePointerInfo::getJumpTable(), MemVT, false, false,
+                        0);
+  Chain = Addr.getValue(1);
+
+  if ((getTargetMachine().getRelocationModel() == Reloc::PIC_) || IsN64) {
+    // For PIC, the sequence is:
+    // BRIND(load(Jumptable + index) + RelocBase)
+    // RelocBase can be JumpTable, GOT or some sort of global base.
+    Addr = DAG.getNode(ISD::ADD, DL, PTy, Addr,
+                       getPICJumpTableRelocBase(Table, DAG));
+  }
+
+  return DAG.getNode(ISD::BRIND, DL, MVT::Other, Chain, Addr);
+}
+
 SDValue MipsTargetLowering::
 LowerBRCOND(SDValue Op, SelectionDAG &DAG) const
 {

lib/Target/Mips/MipsISelLowering.h

@@ -292,6 +292,7 @@ namespace llvm {
                             const SDNode *CallNode, const Type *RetTy) const;
 
     // Lower Operand specifics
+    SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerBRCOND(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerConstantPool(SDValue Op, SelectionDAG &DAG) const;
     SDValue LowerGlobalAddress(SDValue Op, SelectionDAG &DAG) const;

test/CodeGen/Mips/2010-07-20-Switch.ll

@@ -1,6 +1,11 @@
-; RUN: llc < %s -march=mips -relocation-model=static | FileCheck %s -check-prefix=STATIC-O32 
+; RUN: llc < %s -march=mips -relocation-model=static | \
-; RUN: llc < %s -march=mips -relocation-model=pic | FileCheck %s -check-prefix=PIC-O32 
+; RUN: FileCheck %s -check-prefix=STATIC-O32 
-; RUN: llc < %s -march=mips64 -relocation-model=pic -mcpu=mips64 -mattr=n64 | FileCheck %s -check-prefix=PIC-N64
+; RUN: llc < %s -march=mips -relocation-model=pic | \
+; RUN: FileCheck %s -check-prefix=PIC-O32 
+; RUN: llc < %s -march=mips64 -relocation-model=pic -mcpu=mips64 | \
+; RUN: FileCheck %s -check-prefix=N64
+; RUN: llc < %s -march=mips64 -relocation-model=static -mcpu=mips64 | \
+; RUN: FileCheck %s -check-prefix=N64
 
 define i32 @main() nounwind readnone {
 entry:
@@ -17,12 +22,12 @@ entry:
 ; PIC-O32: lw $[[R4:[0-9]+]], %lo($JTI0_0)($[[R2]])
 ; PIC-O32: addu $[[R5:[0-9]+]], $[[R4:[0-9]+]]
 ; PIC-O32: jr  $[[R5]]
-; PIC-N64: dsll $[[R0:[0-9]+]], ${{[0-9]+}}, 3
+; N64: dsll $[[R0:[0-9]+]], ${{[0-9]+}}, 3
-; PIC-N64: ld $[[R1:[0-9]+]], %got_page($JTI0_0)
+; N64: ld $[[R1:[0-9]+]], %got_page($JTI0_0)
-; PIC-N64: daddu $[[R2:[0-9]+]], $[[R0:[0-9]+]], $[[R1]]
+; N64: daddu $[[R2:[0-9]+]], $[[R0:[0-9]+]], $[[R1]]
-; PIC-N64: ld $[[R4:[0-9]+]], %got_ofst($JTI0_0)($[[R2]])
+; N64: ld $[[R4:[0-9]+]], %got_ofst($JTI0_0)($[[R2]])
-; PIC-N64: daddu $[[R5:[0-9]+]], $[[R4:[0-9]+]]
+; N64: daddu $[[R5:[0-9]+]], $[[R4:[0-9]+]]
-; PIC-N64: jr  $[[R5]]
+; N64: jr  $[[R5]]
   switch i32 %0, label %bb4 [
     i32 0, label %bb5
     i32 1, label %bb1
@@ -58,10 +63,10 @@ bb5:                                              ; preds = %entry
 ; PIC-O32: .gpword
 ; PIC-O32: .gpword 
 ; PIC-O32: .gpword 
-; PIC-N64: .align  3
+; N64: .align  3
-; PIC-N64: $JTI0_0:
+; N64: $JTI0_0:
-; PIC-N64: .gpdword
+; N64: .gpdword
-; PIC-N64: .gpdword
+; N64: .gpdword
-; PIC-N64: .gpdword 
+; N64: .gpdword 
-; PIC-N64: .gpdword 
+; N64: .gpdword