Bug 87161 - DFG CSE should do redundant store elimination
Summary: DFG CSE should do redundant store elimination
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: 528+ (Nightly build)
Hardware: All All
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2012-05-22 13:36 PDT by Filip Pizlo
Modified: 2012-05-25 15:47 PDT (History)
0 users

See Also:

Attachments
work in progress (18.34 KB, patch)
2012-05-22 13:38 PDT, Filip Pizlo 		no flags Details | Formatted Diff | Diff
the patch (29.64 KB, patch)
2012-05-22 15:56 PDT, Filip Pizlo 		oliver: review+
Details | Formatted Diff | Diff
the patch (35.49 KB, patch)
2012-05-22 23:12 PDT, Filip Pizlo 		oliver: review+
Details | Formatted Diff | Diff
Show Obsolete (2) View All Add an attachment (proposed patch, testcase, etc.)

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Description Filip Pizlo 2012-05-22 13:36:20 PDT 
Patch forthcoming.
Comment 1 Filip Pizlo 2012-05-22 13:38:19 PDT 
Created attachment 143353 [details]
work in progress
Comment 2 Filip Pizlo 2012-05-22 15:56:21 PDT 
Created attachment 143387 [details]
the patch
Comment 3 Filip Pizlo 2012-05-22 20:19:24 PDT 
Landed in http://trac.webkit.org/changeset/118108
Comment 4 Filip Pizlo 2012-05-22 22:58:50 PDT 
Reopening because the first cut turns out to be wrong.
Comment 5 Filip Pizlo 2012-05-22 23:07:17 PDT 
Rolled out in http://trac.webkit.org/changeset/118126
Comment 6 Filip Pizlo 2012-05-22 23:12:35 PDT 
Created attachment 143470 [details]
the patch

Includes two fixes for handling implicit loads of local variables:

GetScopeChain reads the activation register. Hence, removing a SetLocal to the activation register that is live at the GetScopeChain is wrong.

There are other cases of implicit loads of locals, but they are already marked as either exiting or clobbering, so they are already handled correctly.
Comment 7 Oliver Hunt 2012-05-22 23:42:23 PDT 
Comment on attachment 143470 [details]
the patch

rs=me on some tests for "redundant" store elim on captured variables
Comment 8 Filip Pizlo 2012-05-23 00:30:50 PDT 
Landed in http://trac.webkit.org/changeset/118138

Still trying to figure out reduced tests. Leaving open until I figure it out, or give up.
Comment 9 Filip Pizlo 2012-05-25 15:47:08 PDT 
Merged in http://trac.webkit.org/changeset/118579