Req #71102 [NEW]: Dead code elimination
From: flip101 at gmail dot com
Operating system:
PHP version: Irrelevant
Package: Performance problem
Bug Type: Feature/Change Request
Bug description:Dead code elimination
Description:
------------
When php parses the source files and converts it to bytecode, does it do
dead code elimination? For things like
if (false) {}
or when using constants (self defined or predefined)
or when checking certain expressions such as if (4 > 10-15) {}
I couldn't find anything about this after searching. It would certainly
benefit libraries which have a lot of version checks and checks on which
operating system it's using. To me (unknowingly of anything happening in
the compiler) it seems a bit low hanging fruit optimization, but perhaps
to cover all the edge cases is not so trivial. However a partial
implementation would already help a lot. In case it does exist please
link to relevant documentation or source files.
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Edit bug report at https://bugs.php.net/bug.php?id=71102&edit=1
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Try a snapshot (PHP 5.4): https://bugs.php.net/fix.php?id=71102&r=trysnapshot54
Try a snapshot (PHP 5.5): https://bugs.php.net/fix.php?id=71102&r=trysnapshot55
Try a snapshot (trunk): https://bugs.php.net/fix.php?id=71102&r=trysnapshottrunk
Fixed in SVN: https://bugs.php.net/fix.php?id=71102&r=fixed
Fixed in release: https://bugs.php.net/fix.php?id=71102&r=alreadyfixed
Need backtrace: https://bugs.php.net/fix.php?id=71102&r=needtrace
Need Reproduce Script: https://bugs.php.net/fix.php?id=71102&r=needscript
Try newer version: https://bugs.php.net/fix.php?id=71102&r=oldversion
Not developer issue: https://bugs.php.net/fix.php?id=71102&r=support
Expected behavior: https://bugs.php.net/fix.php?id=71102&r=notwrong
Not enough info: https://bugs.php.net/fix.php?id=71102&r=notenoughinfo
Submitted twice: https://bugs.php.net/fix.php?id=71102&r=submittedtwice
register_globals: https://bugs.php.net/fix.php?id=71102&r=globals
PHP 4 support discontinued: https://bugs.php.net/fix.php?id=71102&r=php4
Daylight Savings: https://bugs.php.net/fix.php?id=71102&r=dst
IIS Stability: https://bugs.php.net/fix.php?id=71102&r=isapi
Install GNU Sed: https://bugs.php.net/fix.php?id=71102&r=gnused
Floating point limitations: https://bugs.php.net/fix.php?id=71102&r=float
No Zend Extensions: https://bugs.php.net/fix.php?id=71102&r=nozend
MySQL Configuration Error: https://bugs.php.net/fix.php?id=71102&r=mysqlcfg
Thread (4 messages)
- flip101 at gmail dot com