[query] no unnecessary object allocations in RegionMemory.allocate #13794
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Consider this:
```scala
class Foo {
def bar(): (Long, Long) = (3, 4)
def destructure(): Unit = {
val (x, y) = bar()
}
def accessors(): Unit = {
val zz = bar()
val x = zz._1
val y = zz._2
}
}
```
These should be exactly equivalent, right? There's no way Scala would compile the match into
something horrible. Right? Right?
```
public void destructure();
Code:
0: aload_0
1: invokevirtual hail-is#27 // Method bar:()Lscala/Tuple2;
4: astore_3
5: aload_3
6: ifnull 35
9: aload_3
10: invokevirtual hail-is#33 // Method scala/Tuple2._1$mcJ$sp:()J
13: lstore 4
15: aload_3
16: invokevirtual hail-is#36 // Method scala/Tuple2._2$mcJ$sp:()J
19: lstore 6
21: new #13 // class scala/Tuple2$mcJJ$sp
24: dup
25: lload 4
27: lload 6
29: invokespecial hail-is#21 // Method scala/Tuple2$mcJJ$sp."<init>":(JJ)V
32: goto 47
35: goto 38
38: new hail-is#38 // class scala/MatchError
41: dup
42: aload_3
43: invokespecial hail-is#41 // Method scala/MatchError."<init>":(Ljava/lang/Object;)V
46: athrow
47: astore_2
48: aload_2
49: invokevirtual hail-is#33 // Method scala/Tuple2._1$mcJ$sp:()J
52: lstore 8
54: aload_2
55: invokevirtual hail-is#36 // Method scala/Tuple2._2$mcJ$sp:()J
58: lstore 10
60: return
public void accessors();
Code:
0: aload_0
1: invokevirtual hail-is#27 // Method bar:()Lscala/Tuple2;
4: astore_1
5: aload_1
6: invokevirtual hail-is#33 // Method scala/Tuple2._1$mcJ$sp:()J
9: lstore_2
10: aload_1
11: invokevirtual hail-is#36 // Method scala/Tuple2._2$mcJ$sp:()J
14: lstore 4
16: return
```
Yeah, so, it extracts the first and second elements of the primitive-specialized tuple, constructs
a `(java.lang.Long, java.lang.Long)` Tuple, then does the match on that.
sigh.
patrick-schultz
previously requested changes
Oct 12, 2023
patrick-schultz
approved these changes
Oct 16, 2023
I was just about to do this then I saw the comment. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Consider this:
These should be exactly equivalent, right? There's no way Scala would compile the match into something horrible. Right? Right?
Yeah, so, it extracts the first and second elements of the primitive-specialized tuple,
constructs aconstructs another primitive-specialized tuple (for no reason???), then does the match on that.(java.lang.Long, java.lang.Long)Tuplesigh.