Bug 133935

Summary: [ftlopt] DFG OSR entry should have a crystal-clear story for when it's safe to enter at a block with a set of values
Product: WebKit Reporter: Filip Pizlo <fpizlo>
Component: JavaScriptCoreAssignee: Filip Pizlo <fpizlo>
Status: RESOLVED FIXED    
Severity: Normal CC: barraclough, ggaren, mark.lam, mhahnenberg, msaboff, oliver, sam
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Bug Depends on:    
Bug Blocks: 133918    
Attachments:
Description Flags
the patch oliver: review+

Filip Pizlo
Reported 2014-06-15 22:06:42 PDT
Currently we record the abstract values at the head of a block at the time that the backend runs. This causes weirdness if a subsequent run of the CFA proves less things (or different things) than a past run, and we had already performed optimizations based on the past run. The solution is to save the intersection of all proofs. This makes constant folding a lot easier to reason about.
Attachments
the patch (15.63 KB, patch)
2014-06-15 22:09 PDT, Filip Pizlo 		oliver: review+
DetailsFormatted DiffDiff
View All Add attachment proposed patch, testcase, etc.
Filip Pizlo
Comment 1 2014-06-15 22:09:19 PDT
Created attachment 233151 [details] the patch
Filip Pizlo
Comment 2 2014-06-16 11:06:51 PDT
Landed in http://trac.webkit.org/changeset/170016
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