Decompose some bitwise operations in HIR to allow more overall optimizations to kick in #104517
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CC. @dotnet/jit-contrib, this is ready for review. It gives some nice improvements on both Arm64 and x64 due to additional optimization opportunities. On xarch in particular it also gives better codegen almost anywhere vpternlog can be used and handles more (but not all) of the possible vpternlog lightups. There are a couple methods where the code size has increased, rather than decreased, due to vpternlog but its a minority overall and typically due to 2 of the inputs being containable. These should be addressable, but I'd rather do that separately since this is still a large net improvement (generally speaking this should entail checking if two operands are containable and opting to not combine them into a vpternlog in that scenario). |
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The SPMI replay failure is #104585 |
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Rerunning now that the SPMI replay issue should be fixed. This should still be ready for review and notably also fixes some issues that were found by antigen |
| // We specially handle this here since we're only producing a | ||
| // native intrinsic node in LIR | ||
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| std::swap(op1, op2); |
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can you remind me - is it fine to do this swap here in terms of side-effect reordering?
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Right, in this case its fine specifically because we've validated we're in LIR already.
Otherwise, we should be applying GTF_REVERSE_OPS or have some comment about expecting the user to have already spilled side effects, etc.
Doing this allows more scenarios involving CSE, morph transforms, and other optimizations to kick in. This will also longer term allow
~Compareto be optimized to the inverse comparison as well.When such optimizations aren't feasible, we still end up getting the good codegen in lowering anyways.