[Codegen][Map] Add PackLayout distribution pattern for transfer_gather#23809
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Groverkss wants to merge 1 commit intoiree-org:mainfrom
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[Codegen][Map] Add PackLayout distribution pattern for transfer_gather#23809Groverkss wants to merge 1 commit intoiree-org:mainfrom
Groverkss wants to merge 1 commit intoiree-org:mainfrom
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Add MapDistributeTransferGather which distributes transfer_gather ops under PackLayoutAttr. Eventually, transfer_read would pre-process to transfer_gather before distribution and distribute as transfer_gather. They eventually canonicalize to an equivalent form after unrolling. Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
Groverkss
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MaheshRavishankar,
Max191,
hanhanW and
qedawkins
as code owners
sommerlukas
reviewed
Mar 17, 2026
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| /// %s1 = vector.step : vector<32xindex> // redistributed → [tid_off + 0, 8, | ||
| /// 16, 24] transfer_gather %mem[%off0, %off1] [%s0, %s1], %pad |
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Nit: The line break here is a bit unfortunate, probably needs manual formatting.
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| if (origDimToSymbol[origDim] >= 0) { | ||
| newSourceResults.push_back( | ||
| getAffineSymbolExpr(origDimToSymbol[origDim], ctx)); | ||
| continue; | ||
| } |
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Can you add a comment what this bit is for?
| SmallVector<Attribute> allMapAttrs; | ||
| allMapAttrs.push_back(AffineMapAttr::get( | ||
| AffineMap::get(distRank, totalSymbols, newSourceResults, ctx))); | ||
| for (auto &mapResults : newIndexVecMapResults) { |
| // Layout (2, 3, 4, 2):(12, 0, 3, 0) has interleaved thread/value leaves: | ||
| // Thread: (2, stride=12), (4, stride=3) → 8 threads | ||
| // Value: (3, dataStride=8), (2, dataStride=1) → distributed shape [3, 2] | ||
| // The two value leaves don't coalesce (3*1 ≠ 8). |
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Why do we multiply with 3 here?
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I think the new indexing maps calculated by distribution are quite important, so I think the test should check them.
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Add MapDistributeTransferGather which distributes transfer_gather ops under PackLayoutAttr.
Eventually, transfer_read would pre-process to transfer_gather before distribution and distribute as transfer_gather. They eventually canonicalize to an equivalent form after unrolling.
Co-Authored-By: Claude Opus 4.6 (1M context) noreply@anthropic.com