refactor[venom]: move commutative instruction set (#4307)

this commit moves the commutative instruction set from
`venom_to_assembly.py` into `basicblock.py` and adds a convenience
method in `IRInstruction`.

vyper/venom/basicblock.py

@@ -82,6 +82,8 @@
 
 CFG_ALTERING_INSTRUCTIONS = frozenset(["jmp", "djmp", "jnz"])
 
+COMMUTATIVE_INSTRUCTIONS = frozenset(["add", "mul", "smul", "or", "xor", "and", "eq"])
+
 if TYPE_CHECKING:
     from vyper.venom.function import IRFunction
 
@@ -235,6 +237,10 @@ def __init__(
     def is_volatile(self) -> bool:
         return self.opcode in VOLATILE_INSTRUCTIONS
 
+    @property
+    def is_commutative(self) -> bool:
+        return self.opcode in COMMUTATIVE_INSTRUCTIONS
+
     @property
     def is_bb_terminator(self) -> bool:
         return self.opcode in BB_TERMINATORS

vyper/venom/venom_to_assembly.py

@@ -103,9 +103,6 @@
     ]
 )
 
-COMMUTATIVE_INSTRUCTIONS = frozenset(["add", "mul", "smul", "or", "xor", "and", "eq"])
-
-
 _REVERT_POSTAMBLE = ["_sym___revert", "JUMPDEST", *PUSH(0), "DUP1", "REVERT"]
 
 
@@ -431,7 +428,7 @@ def _generate_evm_for_instruction(
             # the same variable, however, before a jump that is not possible
             self._stack_reorder(assembly, stack, list(target_stack))
 
-        if opcode in COMMUTATIVE_INSTRUCTIONS:
+        if inst.is_commutative:
             cost_no_swap = self._stack_reorder([], stack, operands, dry_run=True)
             operands[-1], operands[-2] = operands[-2], operands[-1]
             cost_with_swap = self._stack_reorder([], stack, operands, dry_run=True)