[Webkit-unassigned] [Bug 69690] New: DFG does not have flow-sensitive intraprocedural control flow analysis

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=69690

           Summary: DFG does not have flow-sensitive intraprocedural
                    control flow analysis
           Product: WebKit
           Version: 528+ (Nightly build)
          Platform: All
        OS/Version: All
            Status: NEW
          Severity: Normal
          Priority: P2
         Component: JavaScriptCore
        AssignedTo: webkit-unassigned at lists.webkit.org
        ReportedBy: fpizlo at apple.com


Currently the DFG will reperform certain type and safety checks because it forgot that it had already performed them in a previous basic block.

It also sometimes forgets that it had performed checks in the same basic block, if those checks are not captured by either CSE or DataFormat.

One way to ensure that checks are precisely eliminated if all possible paths up to that check already contain that same check (or a stricter check) followed by operations that cannot change the property being checked.  Ascertaining this can be done with a flow-sensitive intraprocedural control flow analysis (CFA), which the DFG currently does not have.

-- 
Configure bugmail: https://bugs.webkit.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.