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| author | Erick Tryzelaar <erick.tryzelaar@gmail.com> | 2013-06-14 16:58:55 -0700 |
|---|---|---|
| committer | Erick Tryzelaar <erick.tryzelaar@gmail.com> | 2013-06-14 16:58:55 -0700 |
| commit | ac83f4b7325eea6ec82db73fb5c1ece7d8320908 (patch) | |
| tree | 292602ebc6a20113f141ce0c1d7595f2359016ee /src/libstd | |
| parent | eadd83da8b9abc821b141195503836b2094a9ea3 (diff) | |
| download | rust-ac83f4b7325eea6ec82db73fb5c1ece7d8320908.tar.gz rust-ac83f4b7325eea6ec82db73fb5c1ece7d8320908.zip | |
std: add a fixme to note performance issues in vec::from_elem.
Diffstat (limited to 'src/libstd')
| -rw-r--r-- | src/libstd/vec.rs | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/src/libstd/vec.rs b/src/libstd/vec.rs index 19233c53348..f6f5b98df67 100644 --- a/src/libstd/vec.rs +++ b/src/libstd/vec.rs @@ -155,8 +155,10 @@ pub fn from_fn<T>(n_elts: uint, op: old_iter::InitOp<T>) -> ~[T] { * to the value `t`. */ pub fn from_elem<T:Copy>(n_elts: uint, t: T) -> ~[T] { - // hack: manually inline from_fn for 2x plus speedup (sadly very important, from_elem is a - // bottleneck in borrowck!) + // FIXME (#7136): manually inline from_fn for 2x plus speedup (sadly very + // important, from_elem is a bottleneck in borrowck!). Unfortunately it + // still is substantially slower than using the unsafe + // vec::with_capacity/ptr::set_memory for primitive types. unsafe { let mut v = with_capacity(n_elts); do as_mut_buf(v) |p, _len| { |