Bug 68127 - DFG JIT should not speculate integer if the value is always going to be used as a double anyway
Summary: DFG JIT should not speculate integer if the value is always going to be used ...
Status: RESOLVED FIXED
Alias: None
Product: WebKit
Classification: Unclassified
Component: JavaScriptCore (show other bugs)
Version: 528+ (Nightly build)
Hardware: All All
: P2 Normal
Assignee: Nobody
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2011-09-14 15:30 PDT by Filip Pizlo
Modified: 2011-09-14 16:06 PDT (History)
0 users

See Also:


Attachments
the patch (6.42 KB, patch)
2011-09-14 15:34 PDT, Filip Pizlo
oliver: review+
Details | Formatted Diff | Diff

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Description Filip Pizlo 2011-09-14 15:30:42 PDT
The DFG JIT will speculate that a value is an integer if the prediction logic tells us so.  But this is dangerously unnecessary if the value will always be used as a double.  For example, if o.f is predicted integer but is always used as o.f * 1.5, then there is no point to speculating that o.f is an integer because even if we do, we still have to convert it to a double.
Comment 1 Filip Pizlo 2011-09-14 15:34:30 PDT
Created attachment 107408 [details]
the patch
Comment 2 Filip Pizlo 2011-09-14 16:06:35 PDT
Landed in r95136.