Restore Vec::from_iter() specialization #37740
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Since I said "no intentional functional change" in the previous commit, I guess it was inevitable there were unintentional changes. Not functional, but optimization-wise. This restores the extend specialization's use in Vec::from_iter.
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Sorry! it's how it is |
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Commit f9b70ac introduced the extend/extend_desugared split, to reduce monomorphization bloat. Since |
Vec::from_iter's general case allocates the vector up front; this is redundant for the TrustedLen case, and can then be avoided to reduce the size of the code.
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@bors: r+ |
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📌 Commit c36edc7 has been approved by |
bors
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Nov 14, 2016
Restore Vec::from_iter() specialization Since I said "no intentional functional change" in the previous commit, I guess it was inevitable there were unintentional changes. Not functional, but optimization-wise. This restores the extend specialization's use in Vec::from_iter. (commit 1). Also use specialization in from_iter to reduce allocation code duplication for the TrustedLen case (commit 2). Bug introduced in PR #37709
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Since I said "no intentional functional change" in the previous commit,
I guess it was inevitable there were unintentional changes. Not
functional, but optimization-wise. This restores the extend
specialization's use in Vec::from_iter. (commit 1).
Also use specialization in from_iter to reduce allocation code duplication
for the TrustedLen case (commit 2).
Bug introduced in PR #37709