Add way to test for builtin TargetOpcode

[arsenm]

Summary

The alternative would be to add a bit to the target's InstrFlags but that seems like a waste of a bit.

[arsenm]

ping

[arsenm]

ping

[arsenm]

ping

[ab]

With '<' -> '<=', seems reasonable.

Can you add a comment? I'm not sure we refer to these as "builtins" anywhere else (not that I have a better name though).

include/llvm/Target/TargetInstrInfo.h

65

<= ?

[MatzeB]

Maybe talk about shared opcodes or generic opcodes to indicate they are not target-specific.

[arsenm]

In D12464#258300, @ab wrote:

With '<' -> '<=', seems reasonable.

Can you add a comment? I'm not sure we refer to these as "builtins" anywhere else (not that I have a better name though).

I got this from the BUILTIN_OP_END. The comment at the start of the enum calls these "Invariant opcodes" but that doesn't sound good. How about isGenericOpcode()?

[arsenm]

r249169 as isGenericOpcode

include/llvm/Target/TargetInstrInfo.h

 public:
   TargetInstrInfo(unsigned CFSetupOpcode = ~0u, unsigned CFDestroyOpcode = ~0u)
     : CallFrameSetupOpcode(CFSetupOpcode),
       CallFrameDestroyOpcode(CFDestroyOpcode) {
   }
 
   virtual ~TargetInstrInfo();
 
+  static bool isBuiltinOpcode(unsigned Opc) {
+    return Opc < TargetOpcode::BUILTIN_OP_END;
+  }
+
   /// Given a machine instruction descriptor, returns the register
   /// class constraint for OpNum, or NULL.
   const TargetRegisterClass *getRegClass(const MCInstrDesc &TID,
                                          unsigned OpNum,
                                          const TargetRegisterInfo *TRI,
                                          const MachineFunction &MF) const;
 
   /// Return true if the instruction is trivially rematerializable, meaning it

include/llvm/Target/TargetOpcodes.h

enum {
   /// frame index of the local stack allocation.
   LOCAL_ESCAPE = 21,
 
   /// Loading instruction that may page fault, bundled with associated
   /// information on how to handle such a page fault.  It is intended to support
   /// "zero cost" null checks in managed languages by allowing LLVM to fold
   /// comparisons into existing memory operations.
   FAULTING_LOAD_OP = 22,
+
+  /// BUILTIN_OP_END - This must be the last enum value in this list.
+  /// The target-specific post-isel opcode values start here.
+  BUILTIN_OP_END = FAULTING_LOAD_OP,
 };
 } // end namespace TargetOpcode
 } // end namespace llvm
 
 #endif