a17f03bd93
We have several bug reports that could be characterized as "reducing scalarization", and this topic was also raised on llvm-dev recently: http://lists.llvm.org/pipermail/llvm-dev/2020-January/138157.html ...so I'm proposing that we deal with these patterns in a new, lightweight IR vector pass that runs before/after other vectorization passes. There are 4 alternate options that I can think of to deal with this kind of problem (and we've seen various attempts at all of these), but they all have flaws: InstCombine - can't happen without TTI, but we don't want target-specific folds there. SDAG - too late to assist other vectorization passes; TLI is not equipped for these kind of cost queries; limited to a single basic block. CGP - too late to assist other vectorization passes; would need to re-implement basic cleanups like CSE/instcombine. SLP - doesn't fit with existing transforms; limited to a single basic block. This initial patch/transform is based on existing code in AggressiveInstCombine: we walk backwards through the function looking for a pattern match. But we diverge from that cost-independent IR canonicalization pass by using TTI to decide if the vector alternative is profitable. We probably have at least 10 similar bug reports/patterns (binops, constants, inserts, cheap shuffles, etc) that would fit in this pass as follow-up enhancements. It's possible that we could iterate on a worklist to fix-point like InstCombine does, but it's safer to start with a most basic case and evolve from there, so I didn't try to do anything fancy with this initial implementation. Differential Revision: https://reviews.llvm.org/D73480
21 lines
390 B
CMake
21 lines
390 B
CMake
add_llvm_component_library(LLVMVectorize
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LoadStoreVectorizer.cpp
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LoopVectorizationLegality.cpp
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LoopVectorize.cpp
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SLPVectorizer.cpp
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Vectorize.cpp
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VectorCombine.cpp
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VPlan.cpp
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VPlanHCFGBuilder.cpp
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VPlanPredicator.cpp
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VPlanSLP.cpp
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VPlanTransforms.cpp
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VPlanVerifier.cpp
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ADDITIONAL_HEADER_DIRS
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${LLVM_MAIN_INCLUDE_DIR}/llvm/Transforms
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DEPENDS
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intrinsics_gen
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)
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