Optimizer: reimplement DeadStoreElimination in swift #67122
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Nice! |
Instead of aliasAnalysis.mayRead(inst: i, fromAddress: a) it's more natural to write i.mayRead(fromAddress: a, aliasAnalysis)
add field types: `x`: existential address projection, like `open_existential_addr` `i<n>`: indexed element with constant index, like `index_addr` with an integer literal as index `i*`: indexed element with an unknown index
* `createStructExtract` * `createStructElementAddr` * `createTupleExtract` * `createTupleElementAddr`
Also add `Value.referenceRoot`
debug_value just "reads" the operand if it is an address.
The old C++ pass didn't catch a few cases. Also: * The new pass is significantly simpler: it doesn't perform dataflow for _all_ memory locations at once using bitfields, but handles each store separately. (In both implementations there is a complexity limit in place to avoid quadratic complexity) * The new pass works with OSSA
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atrick
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Jul 10, 2023
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The Swift utilities all look great!
I don't know if this is the most efficient or powerful global DSE algorithm but it is definitely the easiest to understand and maintain.
@eeckstein I have several requests for clarification in the form of naming, comments, asserts and TODOs which I hope you will consider.
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Addresses review feedback of swiftlang#67122
eeckstein
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Addresses review feedback of swiftlang#67122
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The old C++ pass didn't catch a few cases.
Also: