- // Invariant opcodes: All instruction sets have these as their low opcodes.
- enum {
- PHI = 0,
- INLINEASM = 1,
- DBG_LABEL = 2,
- EH_LABEL = 3,
- GC_LABEL = 4,
-
- /// KILL - This instruction is a noop that is used only to adjust the liveness
- /// of registers. This can be useful when dealing with sub-registers.
- KILL = 5,
-
- /// EXTRACT_SUBREG - This instruction takes two operands: a register
- /// that has subregisters, and a subregister index. It returns the
- /// extracted subregister value. This is commonly used to implement
- /// truncation operations on target architectures which support it.
- EXTRACT_SUBREG = 6,
-
- /// INSERT_SUBREG - This instruction takes three operands: a register
- /// that has subregisters, a register providing an insert value, and a
- /// subregister index. It returns the value of the first register with
- /// the value of the second register inserted. The first register is
- /// often defined by an IMPLICIT_DEF, as is commonly used to implement
- /// anyext operations on target architectures which support it.
- INSERT_SUBREG = 7,
-
- /// IMPLICIT_DEF - This is the MachineInstr-level equivalent of undef.
- IMPLICIT_DEF = 8,
-
- /// SUBREG_TO_REG - This instruction is similar to INSERT_SUBREG except
- /// that the first operand is an immediate integer constant. This constant
- /// is often zero, as is commonly used to implement zext operations on
- /// target architectures which support it, such as with x86-64 (with
- /// zext from i32 to i64 via implicit zero-extension).
- SUBREG_TO_REG = 9,
-
- /// COPY_TO_REGCLASS - This instruction is a placeholder for a plain
- /// register-to-register copy into a specific register class. This is only
- /// used between instruction selection and MachineInstr creation, before
- /// virtual registers have been created for all the instructions, and it's
- /// only needed in cases where the register classes implied by the
- /// instructions are insufficient. The actual MachineInstrs to perform
- /// the copy are emitted with the TargetInstrInfo::copyRegToReg hook.
- COPY_TO_REGCLASS = 10
- };
-