Handle copy on empty str/length zero data#235
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avanhatt merged 4 commits intomodel-checking:main-152-2021-06-17from Jun 22, 2021
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Handle copy on empty str/length zero data#235avanhatt merged 4 commits intomodel-checking:main-152-2021-06-17from
avanhatt merged 4 commits intomodel-checking:main-152-2021-06-17from
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LGTM but we should keep track of the issue appearing in the intrinsic test and provide more information if possible.
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Open an issue regarding these failures.
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Does this fail for both cases or just one? This information would be useful for debugging slice processing.
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Both cases, added a comment to main saying that, thanks.
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| // THIS CHUNK causes 3 failures | |
| // The chunk below causes 3 failures |
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Jun 22, 2021
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Jun 23, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Jul 2, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Jul 9, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Jul 15, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Jul 26, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Aug 2, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Aug 6, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Aug 17, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Aug 24, 2021
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Apr 26, 2022
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Apr 27, 2022
For consistency with LLVM semantics, only codegen an implicit memcpy when the length is nonzero.
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Description of changes:
Rust seems to use a special 0x1 pointer for the empty, length-zero string. C expects memcpy to take valid pointers even when the length of the copy is zero. So, to match LLVM semantics, we should only codegen a memcpy when the length is nonzero.
Resolved issues:
Resolves #234
Call-outs:
One of the test I adds fails not for the copy, but for some code to cast back to a ptr. This is a different issue.
Testing:
How is this change tested?
2 new tests, one for implicit copies and one with an intrinsic. Plus a fixme.
Is this a refactor change?
No
Checklist
By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 and MIT licenses.