c0b82df5f3
This patch adds an additional validation step to ensure that the generated schedule does not violate loop-carried memory dependencies. Prior to this patch, incorrect schedules could be produced due to the lack of checks for the following types of dependencies: - load-to-store backward (from bottom to top within the BB) dependencies - store-to-load dependencies - store-to-store dependencies One possible solution to this issue is to add these dependencies directly to the dependency graph, although doing so may lead to performance degradation. In addition, no known cases of incorrect code generation caused by these missing dependencies have been observed in practice. Given these factors, this patch introduces a post-scheduling validation phase to check for such previously missed dependencies, instead of adding them to the graph before searching for a schedule. Since no actual problems have been identified so far, it is likely that most generated schedules are already valid. Therefore, this additional validation is not expected to cause performance degradation in practice. Split off from #135148 . The remaining tasks are as follows: - Address other missing loop-carried dependencies (e.g., output dependencies between physical registers, barrier instructions, and instructions that may raise floating-point exceptions) - Remove code that are currently retained to maintain the existing behavior but probably unnecessary. - Eliminate `SwingSchedulerDAG::isLoopCarriedDep` and use `SwingSchedulerDDG` to traverse edges after dependency analysis part.
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