tustvold opened a new pull request, #3616:
URL: https://github.com/apache/arrow-rs/pull/3616
# Which issue does this PR close?
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Closes #.
# Rationale for this change
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This reduces the amount of generated LLVM code for arrow-cast by 10%
according to `llvm-lines`.
```
Lines Copies Function name
----- ------ -------------
1149994 (100%) 26363 (100%) (TOTAL)
```
Down to
```
Lines Copies Function name
----- ------ -------------
1004711 (100%) 22241 (100%) (TOTAL)
```
Build times go from
```
________________________________________________________
Executed in 15.47 secs fish external
usr time 97.61 secs 446.00 micros 97.61 secs
sys time 4.21 secs 102.00 micros 4.21 secs
```
To
```
________________________________________________________
Executed in 15.28 secs fish external
usr time 94.61 secs 627.00 micros 94.61 secs
sys time 4.17 secs 0.00 micros 4.17 secs
```
So not hugely noticeable, but every little helps :sweat_smile:
It also makes the code faster, likely by reducing branching
```
string_dictionary_builder/(dict_size:20, len:1000, key_len: 5)
time: [15.543 µs 15.580 µs 15.625 µs]
change: [-11.050% -10.027% -8.8655%] (p = 0.00 <
0.05)
Performance has improved.
Found 18 outliers among 100 measurements (18.00%)
4 (4.00%) low mild
14 (14.00%) high severe
string_dictionary_builder/(dict_size:100, len:1000, key_len: 5)
time: [18.659 µs 18.700 µs 18.740 µs]
change: [-1.8355% -1.6221% -1.3921%] (p = 0.00 <
0.05)
Performance has improved.
string_dictionary_builder/(dict_size:100, len:1000, key_len: 10)
time: [19.782 µs 19.804 µs 19.825 µs]
change: [-1.0721% -0.8720% -0.6280%] (p = 0.00 <
0.05)
Change within noise threshold.
Found 3 outliers among 100 measurements (3.00%)
3 (3.00%) high severe
string_dictionary_builder/(dict_size:100, len:10000, key_len: 10)
time: [156.43 µs 156.50 µs 156.58 µs]
change: [-0.8631% -0.7213% -0.5152%] (p = 0.00 <
0.05)
Change within noise threshold.
Found 10 outliers among 100 measurements (10.00%)
5 (5.00%) high mild
5 (5.00%) high severe
string_dictionary_builder/(dict_size:100, len:10000, key_len: 100)
time: [455.15 µs 455.39 µs 455.62 µs]
change: [-0.0976% -0.0156% +0.0749%] (p = 0.72 >
0.05)
No change in performance detected.
Found 5 outliers among 100 measurements (5.00%)
1 (1.00%) low mild
3 (3.00%) high mild
1 (1.00%) high severe
```
# What changes are included in this PR?
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# Are there any user-facing changes?
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