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[Clang] Do not use memcpy for scalable struct copy.
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Authored by HsiangKai on Mar 30 2021, 6:54 AM.

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Summary

For scalable struct types, we do not know the exact size of the struct. Do not use memcpy for struct copy. We use extractvalue and insertvalue for the purpose.

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HsiangKai created this revision.Mar 30 2021, 6:54 AM
HsiangKai requested review of this revision.Mar 30 2021, 6:54 AM
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craig.topper retitled this revision from [Clang] Do not use memcpy for struct copy. to [Clang] Do not use memcpy for scalable struct copy..Mar 30 2021, 10:15 AM
frasercrmck added inline comments.Mar 31 2021, 6:28 AM
clang/include/clang/AST/Type.h
4627

nit: missing "a": is a sizeless type

clang/lib/CodeGen/CGExprAgg.cpp
2085

Are SrcVec and DestVec the right names here? It took me a while to realise they're not vector types.

2086

We could define Vec inside the loop?

2088

I don't know if getContext().getASTRecordLayout(Record).getFieldCount() is expensive to compute, but this may be recomputing it on every iteration.

HsiangKai updated this revision to Diff 334579.Mar 31 2021, 8:02 PM

Address comments.

HsiangKai marked 4 inline comments as done.Mar 31 2021, 8:03 PM
HsiangKai abandoned this revision.Wed, Jun 2, 7:43 AM