Preserve types on reverse cache reloads - #3156
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Attach the original TypeTree to values restored from reverse caches so nested differentiation can classify cached integer loop indices. Assisted-by: OpenAI Codex
Assisted-by: OpenAI Codex
wsmoses
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Aug 20, 2026
vimarsh6739
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August 20, 2026 17:03
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Ah claude came up with a similar fix in #3202 |
wsmoses
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vchuravy
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Sep 10, 2026
#3156 records the original TypeTree as `!enzyme_type` on values restored from reverse caches, but attaches whatever `TR.query` returns without checking it against the reload's register size. `TypeAnalyzer::considerTBAA` does check, and treats a violation as fatal: if ((size_t)pair.first[0] >= RegSize) { llvm::errs() << " bad enzyme_type " << TT.str() << ...; llvm::report_fatal_error("Canonicalization failed"); } So a tree with an offset past the register size does not degrade the analysis, it aborts the next type analysis run over the generated function -- which is exactly the nested-differentiation case (forward-over-reverse) the metadata was added to serve. Apply the same range check before setting the metadata and drop the tree when it does not hold. Dropping only returns that reload to the pre-#3156 behaviour of an untyped load, which is the conservative direction. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01RD6pJCuKKB1n9L8k2orUua
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Reverse cache reloads created by
lookupMdropped the original TypeTree. Preserve it asenzyme_typemetadata so nested differentiation can classify cached integer loop indices.Adds a focused check to
bsearch2.ll. Tracks EnzymeAD/Enzyme.jl#3472.