| commit | 04e5e643f526090ec872c0e505c487918992e21d | [log] [tgz] |
|---|---|---|
| author | Rahul Yadav <rahul4talk@gmail.com> | Mon Jul 21 17:14:56 2025 +0100 |
| committer | GitHub <noreply@github.com> | Mon Jul 21 17:14:56 2025 +0100 |
| tree | a484658775bfdc16c6b4aac6cd329feaec3e120b | |
| parent | a270fdf3fe58dff7093c8bc1c7ffbd03c0268d66 [diff] |
[VectorCombine] Generalize foldBitOpOfBitcasts to support more cast operations (#148350) This patch generalizes the existing foldBitOpOfBitcasts optimization in the VectorCombine pass to handle additional cast operations beyond just bitcast. Fixes: [#146037](https://github.com/llvm/llvm-project/issues/146037) Summary The optimization now supports folding bitwise operations (AND/OR/XOR) with the following cast operations: - bitcast (original functionality) - trunc (truncate) - sext (sign extend) - zext (zero extend) The transformation pattern is: bitop(castop(x), castop(y)) -> castop(bitop(x, y)) This reduces the number of cast instructions from 2 to 1, improving performance on targets where cast operations are expensive or where performing bitwise operations on narrower types is beneficial. Implementation Details - Renamed foldBitOpOfBitcasts to foldBitOpOfCastops to reflect broader functionality - Extended pattern matching to handle any CastInst operation - Added validation for each cast type's constraints (e.g., trunc requires source > dest) - Updated cost model to use the actual cast opcode - Preserves IR flags from original instructions - Handles multi-use scenarios appropriately Testing - Added comprehensive tests in test/Transforms/VectorCombine/bitop-of-castops.ll - Tests cover all supported cast types with all bitwise operations - Includes negative tests for unsupported patterns - All existing VectorCombine tests pass
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