gh-148211: decompose _POP_TOP_LOAD_CONST_INLINE(_BORROW) in JIT

[NekoAsakura]

The composite uop definitions in bytecodes.c are kept for now — remove_unneeded_uops still produces them as intermediate forms during push/pop cancellation.

cpython/Python/optimizer_analysis.c

Lines 610 to 653 in 4ff8b07

	const uint16_t op_without_push[MAX_UOP_ID + 1] = {
	[_COPY] = _NOP,
	[_LOAD_CONST_INLINE] = _NOP,
	[_LOAD_CONST_INLINE_BORROW] = _NOP,
	[_LOAD_CONST_UNDER_INLINE] = _POP_TOP_LOAD_CONST_INLINE,
	[_LOAD_CONST_UNDER_INLINE_BORROW] = _POP_TOP_LOAD_CONST_INLINE_BORROW,
	[_LOAD_FAST] = _NOP,
	[_LOAD_FAST_BORROW] = _NOP,
	[_LOAD_SMALL_INT] = _NOP,
	[_POP_TOP_LOAD_CONST_INLINE] = _POP_TOP,
	[_POP_TOP_LOAD_CONST_INLINE_BORROW] = _POP_TOP,
	[_POP_TWO_LOAD_CONST_INLINE_BORROW] = _POP_TWO,
	[_POP_CALL_ONE_LOAD_CONST_INLINE_BORROW] = _POP_CALL_ONE,
	[_POP_CALL_TWO_LOAD_CONST_INLINE_BORROW] = _POP_CALL_TWO,
	[_SHUFFLE_2_LOAD_CONST_INLINE_BORROW] = _POP_CALL_ONE_LOAD_CONST_INLINE_BORROW,
	};
	const bool op_skip[MAX_UOP_ID + 1] = {
	[_NOP] = true,
	[_CHECK_VALIDITY] = true,
	[_CHECK_PERIODIC] = true,
	[_SET_IP] = true,
	};
	const uint16_t op_without_pop[MAX_UOP_ID + 1] = {
	[_POP_TOP] = _NOP,
	[_POP_TOP_NOP] = _NOP,
	[_POP_TOP_INT] = _NOP,
	[_POP_TOP_FLOAT] = _NOP,
	[_POP_TOP_UNICODE] = _NOP,
	[_POP_TOP_LOAD_CONST_INLINE] = _LOAD_CONST_INLINE,
	[_POP_TOP_LOAD_CONST_INLINE_BORROW] = _LOAD_CONST_INLINE_BORROW,
	[_POP_TWO] = _POP_TOP,
	[_POP_TWO_LOAD_CONST_INLINE_BORROW] = _POP_TOP_LOAD_CONST_INLINE_BORROW,
	[_POP_CALL_TWO_LOAD_CONST_INLINE_BORROW] = _POP_CALL_ONE_LOAD_CONST_INLINE_BORROW,
	[_POP_CALL_ONE_LOAD_CONST_INLINE_BORROW] = _POP_CALL_LOAD_CONST_INLINE_BORROW,
	[_POP_CALL_TWO] = _POP_CALL_ONE,
	[_POP_CALL_ONE] = _POP_CALL,
	};
	const uint16_t op_without_pop_null[MAX_UOP_ID + 1] = {
	[_POP_CALL] = _POP_TOP,
	[_POP_CALL_LOAD_CONST_INLINE_BORROW] = _POP_TOP_LOAD_CONST_INLINE_BORROW,
	};

Specifically, these composites chain through _POP_TOP_LOAD_CONST_INLINE_BORROW in the op_without_push / op_without_pop / op_without_pop_null tables:

• _POP_TWO_LOAD_CONST_INLINE_BORROW
• _POP_CALL_LOAD_CONST_INLINE_BORROW
• _POP_CALL_ONE_LOAD_CONST_INLINE_BORROW
• _POP_CALL_TWO_LOAD_CONST_INLINE_BORROW
• _SHUFFLE_2_LOAD_CONST_INLINE_BORROW

Additionally, _LOAD_CONST_UNDER_INLINE(_BORROW) references _POP_TOP_LOAD_CONST_INLINE(_BORROW) as a target in op_without_push — those table entries would need updating too.

Once these dependents are decomposed, the definitions can be fully removed.

• Issue: Refactor the JIT uops #148211

[Fidget-Spinner]

Feel free to remove the composite uops altogether, including removing them from remove_unneeded_uops!

[Fidget-Spinner]

Ah wait, it seems this is quite hard to remove from the unneeded ops pass without modifying it heavily. So let's skip that for now. Thanks!

[Fidget-Spinner]

LGTM. Thanks a lot!

[Fidget-Spinner]

Please fix the merge conflicts from the other PR. Thank you!

[NekoAsakura]

Done :)