feat: optimize bytestrings

optimize bytestrings in both codesize and gas

store them in code, and CODECOPY to memory when needed instead of
inlining

vyper/codegen/expr.py

@@ -5,6 +5,7 @@
 from vyper import ast as vy_ast
 from vyper.codegen import external_call, self_call
 from vyper.codegen.core import (
+    _freshname,
     clamp,
     ensure_in_memory,
     get_dyn_array_count,
@@ -137,18 +138,16 @@ def parse_Bytes(self):
 
     def _make_bytelike(self, btype, bytez, bytez_length):
         placeholder = self.context.new_internal_variable(btype)
-        seq = []
-        seq.append(["mstore", placeholder, bytez_length])
-        for i in range(0, len(bytez), 32):
-            seq.append(
-                [
-                    "mstore",
-                    ["add", placeholder, i + 32],
-                    bytes_to_int((bytez + b"\x00" * 31)[i : i + 32]),
-                ]
-            )
+        ret = ["seq"]
+        assert isinstance(bytez, bytes)
+        label = _freshname("bytesdata")
+        len_ = len(bytez)
+        ret.append(["data", label, bytez])
+        ret.append(["codecopy", placeholder + 32, ["symbol", label], len_])
+        ret.append(["mstore", placeholder, len_])
+        ret.append(placeholder)
         return IRnode.from_list(
-            ["seq"] + seq + [placeholder],
+            ret,
             typ=btype,
             location=MEMORY,
             annotation=f"Create {btype}: {bytez}",