Ryotaro Kasuga 9e516f5c58 [MachinePipeliner] Remove isLoopCarriedDep and use DDG (#174394) ...

This patch completely removes `isLoopCarriedDep`, which was used
previously to identify loop-carried dependencies in the DAG. Now that we
have the DDG representation, this special handling is no longer
necessary. Simply replacing its usage with the DDG causes several tests
to fail, since cycle detection takes some of the validation-only edges
in the DDG into account. To address this, this patch introduces extra
edges in the DDG, which are used only for cycle detection and not for
other parts of the pass (e.g., scheduling). The extra edges are
determined to preserve the existing behavior of the pass as closely as
possible, which makes the predicates for adding them somewhat complex.

Split off from #135148, and the final patch in the series for #135148

2026-04-03 10:36:34 +00:00

153 KiB

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