updating domtrees dynamically, removing all unreachable blocks#37882

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vchuravy wants to merge 8 commits intomasterfrom

vc/dynamicdomtree

Commits on Nov 4, 2020

Implement algorithm for updating dominator tree with CFG edge insertions and deletions

yhls
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vchuravy
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Make domtree construction take `Vector{BasicBlock}` as input instead of CFG

yhls
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vchuravy
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Add a domtree to every CFG, avoiding constructing them explicitly when needed

yhls
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vchuravy
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Update domtrees dynamically when CFGs get modified

yhls
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vchuravy
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Update domtree dynamically in `cfg_simplify`

yhls
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vchuravy
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Kill statements in blocks that are unreachable, add tests for killing edges

yhls
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vchuravy
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Fix infinite loop bug in `kill_edge!`

yhls
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vchuravy
committed
Enable CFG transforms; turn DCE back on globally

yhls
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vchuravy
committed