1c48d52bb1
This CL improves the performance of creating [...a, b] or [...a]. If the array literal has a leading spread, this CL emits the bytecode [CreateArrayFromIterable] to create the literal. CreateArrayFromIterable is implemented by [IterableToListDefault] builtin to create the initial array for the leading spread. IterableToListDefault has a fast path to clone efficiently if the spread is an actual array. The bytecode generated is now shorter. Bytecode generation is refactored into to BuildCreateArrayLiteral, which allows VisitCallSuper to benefit from this optimization also. For now, turbofan also lowers the bytecode to the builtin. The idiomatic use of [...a] to clone the array a now performs better than a simple for-loop, but still does not match the performance of slice. Bug: v8:7980 Cq-Include-Trybots: luci.v8.try:v8_linux_noi18n_rel_ng Change-Id: Ibde659c82d3c7aa1b1777a3d2f6426ac8cc15e35 Reviewed-on: https://chromium-review.googlesource.com/1181024 Reviewed-by: Ross McIlroy <rmcilroy@chromium.org> Reviewed-by: Sigurd Schneider <sigurds@chromium.org> Reviewed-by: Jakob Gruber <jgruber@chromium.org> Reviewed-by: Georg Neis <neis@chromium.org> Commit-Queue: Georg Neis <neis@chromium.org> Commit-Queue: Hai Dang <dhai@google.com> Cr-Commit-Position: refs/heads/master@{#55520} |
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