34a1888bea
Introduce a lightweight, targeted dead-op eliminator that complements the existing liveness-based runRegionDCE. The algorithm is O(ops): step 1 walks each op in reverse program order, erases it outright if trivially dead, or recurses into nested regions when recursive cleanup is enabled; step 2 drives a per-region worklist that only ever holds ops already verified dead, propagating new deadness by dropping each operand's use before re-checking isOpTriviallyDead on the defining op. Unlike runRegionDCE, this does not touch dead block arguments, dead successor operands, or dead use-def cycles. Use runRegionDCE when those are required. An includeNestedRegions parameter lets callers restrict simplification to the top-level region. Switch transform.apply_dce to use the new helper, dropping a custom worklist that had subtle invariants: SetVector dedup, linear search on every erase, and pre-order walk with skip. In general it is bad practice to implement complex custom logic in Transform ops apply methods: this should be an adaptor exposing MLIR transformations to the transform dialect; non-trivial logic deserves a public API for reusability and proper layering. Introduce a TrivialDeadCodeEliminationPass exposed as -trivial-dce. The pass removes trivially dead operations and, when removeBlocks is enabled, unreachable blocks. It does not run liveness analysis and does not remove dead use-def cycles. Add recursive and removeBlocks options, both defaulting to true, to control whether nested regions are visited and whether unreachable blocks are erased. Assisted-by: Claude Code
46 lines
893 B
CMake
46 lines
893 B
CMake
add_subdirectory(Utils)
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add_mlir_library(MLIRTransforms
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Canonicalizer.cpp
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CompositePass.cpp
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ControlFlowSink.cpp
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CSE.cpp
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TrivialDeadCodeElimination.cpp
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GenerateRuntimeVerification.cpp
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BubbleDownMemorySpaceCasts.cpp
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InlinerPass.cpp
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LocationSnapshot.cpp
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LoopInvariantCodeMotion.cpp
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Mem2Reg.cpp
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OpStats.cpp
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PrintIR.cpp
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RemoveDeadValues.cpp
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SCCP.cpp
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SROA.cpp
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StripDebugInfo.cpp
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SymbolDCE.cpp
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SymbolPrivatize.cpp
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TopologicalSort.cpp
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ViewOpGraph.cpp
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ADDITIONAL_HEADER_DIRS
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${MLIR_MAIN_INCLUDE_DIR}/mlir/Transforms
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DEPENDS
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MLIRTransformsPassIncGen
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MLIRTransformsDialectInterfaceIncGen
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LINK_LIBS PUBLIC
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MLIRAnalysis
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MLIRFunctionInterfaces
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MLIRLoopLikeInterface
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MLIRMemOpInterfaces
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MLIRMemorySlotInterfaces
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MLIRPass
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MLIRRuntimeVerifiableOpInterface
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MLIRSideEffectInterfaces
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MLIRSupport
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MLIRTransformUtils
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MLIRUBDialect
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)
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