Bug 37387

Summary:

Compiler generates unnecessary byte codes

Product:

[Eclipse Project] JDT

Reporter:

Andreas Winter <andreas.winter>

Component:

Core

Assignee:

Olivier Thomann <Olivier_Thomann>

Status:

VERIFIED FIXED

QA Contact:

Severity:

normal

Priority:

CC:

andreas.winter

Version:

2.1

Target Milestone:

2.1.1

Hardware:

OS:

Windows 2000

Whiteboard:

Attachments:

Description	Flags
Fix proposal	none

Description Andreas Winter

2003-05-08 10:39:53 EDT

Compiling 
   private static final Object X[] = new Object[]{null,null}
yields much longer byte code in Eclipse 2.1.1 (200305071103) than in 2.0.2
(200211071448).
The compiler generates unnecessary stores for the null values.

Comment 1 Olivier Thomann

2003-05-08 12:55:11 EDT

The reason is that we no longer consider null has a constant. This case could
still be optimized. I will investigate.

Comment 2 Olivier Thomann

2003-05-08 13:04:05 EDT

Created attachment 4825 [details]
Fix proposal

Philippe, I attached a patch that optimizes this case. We now generate the same
bytecodes than jikes. javac 1.4.1_02 or 1.4.2b21 still generate the whole array
initializer. Let me know if you want me to release it.

Comment 3 Philipe Mulet

2003-05-12 06:04:35 EDT

Please release this patch. Indeed, I forgot about this codegen optimization 
when removing null constant expressions.

Comment 4 Philipe Mulet

2003-05-12 06:04:59 EDT

Olivier, also backport it to 2.1 maintenance stream.

Comment 5 Olivier Thomann

2003-05-12 10:45:11 EDT

Fixed and released in HEAD stream.

Comment 6 Olivier Thomann

2003-05-12 10:55:12 EDT

Backported to 2.1 maintenance stream.

Comment 7 Olivier Thomann

2003-05-12 11:39:57 EDT

Regression test added.

Comment 8 David Audel

2003-06-06 07:02:28 EDT

Verified.