Bug 137161

Summary: DFG shouldn't insert store barriers when it has it on good authority that we're not storing a cell
Product: WebKit Reporter: Filip Pizlo <fpizlo>
Component: JavaScriptCoreAssignee: Filip Pizlo <fpizlo>
Status: RESOLVED FIXED    
Severity: Normal CC: barraclough, ggaren, mark.lam, mhahnenb, msaboff, oliver, ossy, sam
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Bug Depends on: 137340    
Bug Blocks:    
Attachments:
Description Flags
the patch mhahnenb: review+

Description Filip Pizlo 2014-09-26 15:47:53 PDT 
Patch forthcoming.
Comment 1 Filip Pizlo 2014-09-26 15:48:57 PDT 
Created attachment 238742 [details]
the patch
Comment 2 Mark Hahnenberg 2014-09-26 15:51:03 PDT 
Comment on attachment 238742 [details]
the patch

r=me!
Comment 3 Filip Pizlo 2014-09-26 15:54:06 PDT 
Landed in http://trac.webkit.org/changeset/174025
Comment 5 Filip Pizlo 2014-09-27 11:02:21 PDT 
(In reply to comment #4)
> (In reply to comment #3)
> > Landed in http://trac.webkit.org/changeset/174025
> 
> It made 3-4 performance tests crash everywhere:
> - Apple Mountain Lion: https://build.webkit.org/builders/Apple%20MountainLion%20Release%20%28Perf%29/builds/10126
> - Apple Mavericks: https://build.webkit.org/builders/Apple%20Mavericks%20Release%20%28Perf%29/builds/2663
> - EFL: https://build.webkit.org/builders/EFL%20Linux%2064-bit%20Release%20WK2%20%28Perf%29/builds/3310

Ok, I will look. 

The consensus last us GC people chatted was that the barriers that this patch removed were merely masking the lack of barriers elsewhere. I'd rather fix those other barriers directly rather than rolling this out.
Comment 6 Mark Lam 2014-10-13 17:43:27 PDT 
For the record, there was a follow up fix to this patch.  The fix was landed in r174121: <http://trac.webkit.org/r174121> by pizlo.