[BPF] use target triple for pattern predicates (llvm#74998)

This is used for eliminate uses of "CurDAG", which is SelectionDAG-spec,
and not compatible with GIsel algorithms.

(NFC)

Author: inclyc

llvm/lib/Target/BPF/BPFInstrInfo.td

@@ -49,8 +49,8 @@ def BPFWrapper      : SDNode<"BPFISD::Wrapper", SDT_BPFWrapper>;
 def BPFmemcpy       : SDNode<"BPFISD::MEMCPY", SDT_BPFMEMCPY,
                              [SDNPHasChain, SDNPInGlue, SDNPOutGlue,
                               SDNPMayStore, SDNPMayLoad]>;
-def BPFIsLittleEndian : Predicate<"CurDAG->getDataLayout().isLittleEndian()">;
-def BPFIsBigEndian    : Predicate<"!CurDAG->getDataLayout().isLittleEndian()">;
+def BPFIsLittleEndian : Predicate<"Subtarget->isLittleEndian()">;
+def BPFIsBigEndian    : Predicate<"!Subtarget->isLittleEndian()">;
 def BPFHasALU32 : Predicate<"Subtarget->getHasAlu32()">;
 def BPFNoALU32 : Predicate<"!Subtarget->getHasAlu32()">;
 def BPFHasLdsx : Predicate<"Subtarget->hasLdsx()">;

llvm/lib/Target/BPF/BPFSubtarget.cpp

@@ -93,4 +93,6 @@ BPFSubtarget::BPFSubtarget(const Triple &TT, const std::string &CPU,
                            const std::string &FS, const TargetMachine &TM)
     : BPFGenSubtargetInfo(TT, CPU, /*TuneCPU*/ CPU, FS),
       FrameLowering(initializeSubtargetDependencies(CPU, FS)),
-      TLInfo(TM, *this) {}
+      TLInfo(TM, *this) {
+  IsLittleEndian = TT.isLittleEndian();
+}

llvm/lib/Target/BPF/BPFSubtarget.h

@@ -43,6 +43,8 @@ class BPFSubtarget : public BPFGenSubtargetInfo {
   // unused
   bool isDummyMode;
 
+  bool IsLittleEndian;
+
   // whether the cpu supports jmp ext
   bool HasJmpExt;
 
@@ -81,6 +83,8 @@ class BPFSubtarget : public BPFGenSubtargetInfo {
   bool hasGotol() const { return HasGotol; }
   bool hasStoreImm() const { return HasStoreImm; }
 
+  bool isLittleEndian() const { return IsLittleEndian; }
+
   const BPFInstrInfo *getInstrInfo() const override { return &InstrInfo; }
   const BPFFrameLowering *getFrameLowering() const override {
     return &FrameLowering;