Bug 87682

Summary: DFG should not generate code for code that the CFA proves to be unreachable
Product: WebKit Reporter: Filip Pizlo <fpizlo>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal    
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Attachments:
Description Flags
the patch
none
the patch sam: review+

Filip Pizlo
Reported 2012-05-28 16:56:38 PDT
When the CFA proves code to be unreachable, we are stuck in a bit of a conundrum. The code must still be known to other parts of the compiler because of OSR exit liveness issues, so it cannot be simply jettisoned. But we shouldn't be spending time generating that code, and we shouldn't be allowing OSR entry into that code.
Attachments
the patch (4.39 KB, patch)
2012-05-28 17:01 PDT, Filip Pizlo 		no flags
DetailsFormatted DiffDiff
the patch (6.92 KB, patch)
2012-05-28 19:09 PDT, Filip Pizlo 		sam: review+
DetailsFormatted DiffDiff
Show Obsolete (1) View All Add attachment proposed patch, testcase, etc.
Filip Pizlo
Comment 1 2012-05-28 17:01:02 PDT
Created attachment 144410 [details] the patch
Filip Pizlo
Comment 2 2012-05-28 19:09:56 PDT
Created attachment 144425 [details] the patch Cleaned up constant folding a bit more.
Filip Pizlo
Comment 3 2012-05-28 19:43:56 PDT
Landed in http://trac.webkit.org/changeset/118715
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