Revert "[NVPTX] support switch statement with brx.idx" (#102530)

Reverts #102400

Causes LLVM to crash on some tests.

llvm/include/llvm/CodeGen/TargetLowering.h

@@ -3843,10 +3843,6 @@ class TargetLowering : public TargetLoweringBase {
   /// returned value is a member of the MachineJumpTableInfo::JTEntryKind enum.
   virtual unsigned getJumpTableEncoding() const;
 
-  virtual MVT getJumpTableRegTy(const DataLayout &DL) const {
-    return getPointerTy(DL);
-  }
-
   virtual const MCExpr *
   LowerCustomJumpTableEntry(const MachineJumpTableInfo * /*MJTI*/,
                             const MachineBasicBlock * /*MBB*/, unsigned /*uid*/,

llvm/lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -2977,7 +2977,7 @@ void SelectionDAGBuilder::visitJumpTable(SwitchCG::JumpTable &JT) {
   // Emit the code for the jump table
   assert(JT.SL && "Should set SDLoc for SelectionDAG!");
   assert(JT.Reg != -1U && "Should lower JT Header first!");
-  EVT PTy = DAG.getTargetLoweringInfo().getJumpTableRegTy(DAG.getDataLayout());
+  EVT PTy = DAG.getTargetLoweringInfo().getPointerTy(DAG.getDataLayout());
   SDValue Index = DAG.getCopyFromReg(getControlRoot(), *JT.SL, JT.Reg, PTy);
   SDValue Table = DAG.getJumpTable(JT.JTI, PTy);
   SDValue BrJumpTable = DAG.getNode(ISD::BR_JT, *JT.SL, MVT::Other,
@@ -3005,13 +3005,12 @@ void SelectionDAGBuilder::visitJumpTableHeader(SwitchCG::JumpTable &JT,
   // This value may be smaller or larger than the target's pointer type, and
   // therefore require extension or truncating.
   const TargetLowering &TLI = DAG.getTargetLoweringInfo();
-  SwitchOp =
-      DAG.getZExtOrTrunc(Sub, dl, TLI.getJumpTableRegTy(DAG.getDataLayout()));
+  SwitchOp = DAG.getZExtOrTrunc(Sub, dl, TLI.getPointerTy(DAG.getDataLayout()));
 
   unsigned JumpTableReg =
-      FuncInfo.CreateReg(TLI.getJumpTableRegTy(DAG.getDataLayout()));
-  SDValue CopyTo =
-      DAG.getCopyToReg(getControlRoot(), dl, JumpTableReg, SwitchOp);
+      FuncInfo.CreateReg(TLI.getPointerTy(DAG.getDataLayout()));
+  SDValue CopyTo = DAG.getCopyToReg(getControlRoot(), dl,
+                                    JumpTableReg, SwitchOp);
   JT.Reg = JumpTableReg;
 
   if (!JTH.FallthroughUnreachable) {

llvm/lib/Target/NVPTX/NVPTXISelLowering.cpp

@@ -25,7 +25,6 @@
 #include "llvm/CodeGen/Analysis.h"
 #include "llvm/CodeGen/ISDOpcodes.h"
 #include "llvm/CodeGen/MachineFunction.h"
-#include "llvm/CodeGen/MachineJumpTableInfo.h"
 #include "llvm/CodeGen/MachineMemOperand.h"
 #include "llvm/CodeGen/SelectionDAG.h"
 #include "llvm/CodeGen/SelectionDAGNodes.h"
@@ -583,7 +582,9 @@ NVPTXTargetLowering::NVPTXTargetLowering(const NVPTXTargetMachine &TM,
   setOperationAction(ISD::ROTR, MVT::i8, Expand);
   setOperationAction(ISD::BSWAP, MVT::i16, Expand);
 
-  setOperationAction(ISD::BR_JT, MVT::Other, Custom);
+  // Indirect branch is not supported.
+  // This also disables Jump Table creation.
+  setOperationAction(ISD::BR_JT, MVT::Other, Expand);
   setOperationAction(ISD::BRIND, MVT::Other, Expand);
 
   setOperationAction(ISD::GlobalAddress, MVT::i32, Custom);
@@ -944,9 +945,6 @@ const char *NVPTXTargetLowering::getTargetNodeName(unsigned Opcode) const {
     MAKE_CASE(NVPTXISD::Dummy)
     MAKE_CASE(NVPTXISD::MUL_WIDE_SIGNED)
     MAKE_CASE(NVPTXISD::MUL_WIDE_UNSIGNED)
-    MAKE_CASE(NVPTXISD::BrxEnd)
-    MAKE_CASE(NVPTXISD::BrxItem)
-    MAKE_CASE(NVPTXISD::BrxStart)
     MAKE_CASE(NVPTXISD::Tex1DFloatS32)
     MAKE_CASE(NVPTXISD::Tex1DFloatFloat)
     MAKE_CASE(NVPTXISD::Tex1DFloatFloatLevel)
@@ -2787,8 +2785,6 @@ NVPTXTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
     return LowerFP_ROUND(Op, DAG);
   case ISD::FP_EXTEND:
     return LowerFP_EXTEND(Op, DAG);
-  case ISD::BR_JT:
-    return LowerBR_JT(Op, DAG);
   case ISD::VAARG:
     return LowerVAARG(Op, DAG);
   case ISD::VASTART:
@@ -2814,41 +2810,6 @@ NVPTXTargetLowering::LowerOperation(SDValue Op, SelectionDAG &DAG) const {
   }
 }
 
-SDValue NVPTXTargetLowering::LowerBR_JT(SDValue Op, SelectionDAG &DAG) const {
-  SDLoc DL(Op);
-  SDValue Chain = Op.getOperand(0);
-  const auto *JT = cast<JumpTableSDNode>(Op.getOperand(1));
-  SDValue Index = Op.getOperand(2);
-
-  unsigned JId = JT->getIndex();
-  MachineJumpTableInfo *MJTI = DAG.getMachineFunction().getJumpTableInfo();
-  ArrayRef<MachineBasicBlock *> MBBs = MJTI->getJumpTables()[JId].MBBs;
-
-  SDValue IdV = DAG.getConstant(JId, DL, MVT::i32);
-
-  // Generate BrxStart node
-  SDVTList VTs = DAG.getVTList(MVT::Other, MVT::Glue);
-  Chain = DAG.getNode(NVPTXISD::BrxStart, DL, VTs, Chain, IdV);
-
-  // Generate BrxItem nodes
-  assert(!MBBs.empty());
-  for (MachineBasicBlock *MBB : MBBs.drop_back())
-    Chain = DAG.getNode(NVPTXISD::BrxItem, DL, VTs, Chain.getValue(0),
-                        DAG.getBasicBlock(MBB), Chain.getValue(1));
-
-  // Generate BrxEnd nodes
-  SDValue EndOps[] = {Chain.getValue(0), DAG.getBasicBlock(MBBs.back()), Index,
-                      IdV, Chain.getValue(1)};
-  SDValue BrxEnd = DAG.getNode(NVPTXISD::BrxEnd, DL, VTs, EndOps);
-
-  return BrxEnd;
-}
-
-// This will prevent AsmPrinter from trying to print the jump tables itself.
-unsigned NVPTXTargetLowering::getJumpTableEncoding() const {
-  return MachineJumpTableInfo::EK_Inline;
-}
-
 // This function is almost a copy of SelectionDAG::expandVAArg().
 // The only diff is that this one produces loads from local address space.
 SDValue NVPTXTargetLowering::LowerVAARG(SDValue Op, SelectionDAG &DAG) const {

llvm/lib/Target/NVPTX/NVPTXISelLowering.h

@@ -62,9 +62,6 @@ enum NodeType : unsigned {
   BFI,
   PRMT,
   DYNAMIC_STACKALLOC,
-  BrxStart,
-  BrxItem,
-  BrxEnd,
   Dummy,
 
   LoadV2 = ISD::FIRST_TARGET_MEMORY_OPCODE,
@@ -583,11 +580,6 @@ class NVPTXTargetLowering : public TargetLowering {
     return true;
   }
 
-  // The default is the same as pointer type, but brx.idx only accepts i32
-  MVT getJumpTableRegTy(const DataLayout &) const override { return MVT::i32; }
-
-  unsigned getJumpTableEncoding() const override;
-
   bool enableAggressiveFMAFusion(EVT VT) const override { return true; }
 
   // The default is to transform llvm.ctlz(x, false) (where false indicates that
@@ -645,8 +637,6 @@ class NVPTXTargetLowering : public TargetLowering {
 
   SDValue LowerSelect(SDValue Op, SelectionDAG &DAG) const;
 
-  SDValue LowerBR_JT(SDValue Op, SelectionDAG &DAG) const;
-
   SDValue LowerVAARG(SDValue Op, SelectionDAG &DAG) const;
   SDValue LowerVASTART(SDValue Op, SelectionDAG &DAG) const;
 

llvm/lib/Target/NVPTX/NVPTXInstrInfo.td

@@ -3880,44 +3880,6 @@ def DYNAMIC_STACKALLOC64 :
             [(set Int64Regs:$ptr, (dyn_alloca Int64Regs:$size, (i32 timm:$align)))]>,
             Requires<[hasPTX<73>, hasSM<52>]>;
 
-
-//
-// BRX
-//
-
-def SDTBrxStartProfile : SDTypeProfile<0, 1, [SDTCisInt<0>]>;
-def SDTBrxItemProfile : SDTypeProfile<0, 1, [SDTCisVT<0, OtherVT>]>;
-def SDTBrxEndProfile : SDTypeProfile<0, 3, [SDTCisVT<0, OtherVT>, SDTCisInt<1>, SDTCisInt<2>]>;
-
-def brx_start :
-  SDNode<"NVPTXISD::BrxStart", SDTBrxStartProfile,
-         [SDNPHasChain, SDNPOutGlue, SDNPSideEffect]>;
-def brx_item :
-  SDNode<"NVPTXISD::BrxItem", SDTBrxItemProfile,
-         [SDNPHasChain, SDNPOutGlue, SDNPInGlue, SDNPSideEffect]>;
-def brx_end :
-  SDNode<"NVPTXISD::BrxEnd", SDTBrxEndProfile,
-         [SDNPHasChain, SDNPInGlue, SDNPSideEffect]>;
-
-let isTerminator = 1, isBranch = 1, isIndirectBranch = 1 in {
-
-  def BRX_START :
-    NVPTXInst<(outs), (ins i32imm:$id),
-              "$$L_brx_$id: .branchtargets",
-              [(brx_start (i32 imm:$id))]>;
-
-  def BRX_ITEM :
-    NVPTXInst<(outs), (ins brtarget:$target),
-              "\t$target,",
-              [(brx_item bb:$target)]>;
-
-  def BRX_END :
-    NVPTXInst<(outs), (ins brtarget:$target, Int32Regs:$val, i32imm:$id),
-              "\t$target;\n\tbrx.idx \t$val, $$L_brx_$id;",
-              [(brx_end bb:$target, (i32 Int32Regs:$val), (i32 imm:$id))]>;
-}
-
-
 include "NVPTXIntrinsics.td"
 
 //-----------------------------------