GH-91432: Specialize FOR_ITER (GH-91713)

* Adds FOR_ITER_LIST and FOR_ITER_RANGE specializations.

* Adds _PyLong_AssignValue() internal function to avoid temporary boxing of ints.

1 files changed, 9 insertions, 3 deletions

diff --git a/Lib/dis.py b/Lib/dis.py
index 355f468301..bd87de97fc 100644
--- a/Lib/dis.py
+++ b/Lib/dis.py
@@ -37,6 +37,7 @@ LOAD_CONST = opmap['LOAD_CONST']
 LOAD_GLOBAL = opmap['LOAD_GLOBAL']
 BINARY_OP = opmap['BINARY_OP']
 JUMP_BACKWARD = opmap['JUMP_BACKWARD']
+FOR_ITER = opmap['FOR_ITER']
 LOAD_ATTR = opmap['LOAD_ATTR']
 
 CACHE = opmap["CACHE"]
@@ -476,6 +477,8 @@ def _get_instructions_bytes(code, varname_from_oparg=None,
             elif deop in hasjrel:
                 signed_arg = -arg if _is_backward_jump(deop) else arg
                 argval = offset + 2 + signed_arg*2
+                if deop == FOR_ITER:
+                    argval += 2
                 argrepr = "to " + repr(argval)
             elif deop in haslocal or deop in hasfree:
                 argval, argrepr = _get_name_info(arg, varname_from_oparg)
@@ -629,11 +632,14 @@ def findlabels(code):
     labels = []
     for offset, op, arg in _unpack_opargs(code):
         if arg is not None:
-            if op in hasjrel:
-                if _is_backward_jump(op):
+            deop = _deoptop(op)
+            if deop in hasjrel:
+                if _is_backward_jump(deop):
                     arg = -arg
                 label = offset + 2 + arg*2
-            elif op in hasjabs:
+                if deop == FOR_ITER:
+                    label += 2
+            elif deop in hasjabs:
                 label = arg*2
             else:
                 continue