RFR: 8302850: Implement C1 clone intrinsic that reuses arraycopy code for primitive arrays [v6]

[Galder Zamarreño]

On Tue, 12 Mar 2024 18:16:24 GMT, Dean Long <dlong at openjdk.org> wrote:

> IR expansion in append_alloc_array_copy() looks unconditional. What's going to happen on platforms with no back-end support?

I might be wrong but the way I understood the code, I think other platforms will have no issue with that with the way the current code works:

The check I added in `Compiler::is_intrinsic_supported()` means that for clone calls in other platforms it would return false. If that returns false, `AbstractCompiler::is_intrinsic_available` will return false. Then this means that in `GraphBuilder::try_inline_intrinsics` `is_available` would be false, in which case the method will always return false and `build_graph_for_intrinsic` will not be called. `GraphBuilder::append_alloc_array_copy` is called from `build_graph_for_intrinsic`, so I don't see a danger of that being called for non-supported platforms.

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PR Comment: https://git.openjdk.org/jdk/pull/17667#issuecomment-1997319836