Bug 191729

Summary: KnownCellUse should also have SpecCellCheck as its type filter
Product: WebKit Reporter: Saam Barati <saam>
Component: JavaScriptCoreAssignee: Saam Barati <saam>
Status: RESOLVED FIXED    
Severity: Normal CC: benjamin, commit-queue, fpizlo, ggaren, gskachkov, keith_miller, mark.lam, msaboff, rmorisset, ticaiolima, webkit-bug-importer, ysuzuki
Priority: P2 Keywords: InRadar
Version: WebKit Nightly Build   
Hardware: Unspecified   
OS: Unspecified   
Attachments:
Description Flags
patch none

Saam Barati
Reported 2018-11-15 17:53:18 PST
We write transformations in the compiler like this where we emit edges with KnownCellUse if we know we're inserting code at a point where we're dominated by a Cell check: a: SomeValue b: Something(Cell:@a) c: SomethingElse(@b) d: CheckNotEmpty(@a) => a: SomeValue b: Something(Cell:@a) e: RandomOtherThing(KnownCellUse:@a) c: SomethingElse(@b) d: CheckNotEmpty(@a) However, doing this may lead to subtly incorrect programs since KnownCellUse doesn't allow the empty value to flow through it. We end up deleting @d in the above program, which is wrong. We need to have KnownCellUse allow the empty value to flow through.
Attachments
patch (3.57 KB, patch)
2018-11-15 17:59 PST, Saam Barati 		no flags
DetailsFormatted DiffDiff
View All Add attachment proposed patch, testcase, etc.
Saam Barati
Comment 1 2018-11-15 17:53:53 PST
<rdar://problem/45872852>
Saam Barati
Comment 2 2018-11-15 17:59:35 PST
Created attachment 355005 [details] patch
WebKit Commit Bot
Comment 3 2018-11-16 12:43:01 PST
Comment on attachment 355005 [details] patch Clearing flags on attachment: 355005 Committed r238297: <https://trac.webkit.org/changeset/238297>
WebKit Commit Bot
Comment 4 2018-11-16 12:43:03 PST
All reviewed patches have been landed. Closing bug.
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