lidavidm commented on pull request #10350: URL: https://github.com/apache/arrow/pull/10350#issuecomment-865118448
It looks like the difference is that here the shift amount is reduced modulo the type precision (what x86 generally does but *not* what ARM does, e.g. see this post about [MSVC on ARM](https://devblogs.microsoft.com/cppblog/hello-arm-exploring-undefined-unspecified-and-implementation-defined-behavior-in-c/#shift-operators); allows negative shifts) and in the other PR, such shifts (including negative shifts) are disallowed (following the C++ specification). The Arrow Compute behavior reflects the presence of having checked/unchecked variants; it seems the Gandiva variants must always produce a result? But it would be good to have them agree. Looking at some other systems: - T-SQL (MS SQL Server) has no bit-shift operators, - Postgres doesn't specify a behavior. - Python disallows negative shift values (overflow doesn't apply due to infinite-precision integers) -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
