Fix zero-loop sync propagation

[zhangstevenunity]

Summary

• distinguish may-zero-trip loops from definitely-entered loops
• keep conditional finder propagation for may-skip regions only
• restore transitive alreadySync guard for conditional finders
• update regression coverage for nested loop same-pipe pairing

Test

• issue533_loop_zero_trip_sync_regression
• issue564_k_loop_mte1_mte2_wait_regression
• issue454_nested_loop_same_pipe_pair_regression
• issue428_cube_sync_regression

[gemini-code-assist]

Code Review

This pull request introduces a mechanism to track synchronization operations within potentially skipped code regions, such as zero-trip loops and if-statements without an else branch, to ensure correct synchronization state propagation. It adds a "mayZeroTrip" flag to loop elements and implements logic to mark sync entries as conditional. A review comment identifies an opportunity to optimize loops that are guaranteed to execute by fully propagating their synchronization state, which would prevent redundant synchronization operations.

[gemini-code-assist]

For loops that are definitely entered (mayZeroTrip is false), the synchronization state established within the loop body (including alreadySync) should be fully propagated to the outer context. The current implementation only copies syncFinder and syncFinderIsConditional, which may lead to redundant synchronization operations being inserted later because the transitive elimination logic won't see the alreadySync status from the body.

Suggested change

	syncRecordList[bufferIdx].syncFinder =
	syncRecordForList[bufferIdx].syncFinder;
	syncRecordList[bufferIdx].syncFinderIsConditional =
	syncRecordForList[bufferIdx].syncFinderIsConditional;
	syncRecordList[bufferIdx] = syncRecordForList[bufferIdx];

[reedhecre]

Codex Review

该评论由 review 机器人自动更新。

• PR: Fix zero-loop sync propagation #585 Fix zero-loop sync propagation
• Author: zhangstevenunity
• Base/Head: main / codex/fix-zero-loop-sync
• Head SHA: 0b0e3c194c88
• Trigger: 检测到新的 open PR
• Generated At: 2026-04-26T05:35:12Z
• Status: completed

Summary

未检查到 PR #585 存在问题

Findings

No issues found.