Last Comment Bug 729725 - IonMonkey: MTruncateToInt32 should support constant folding
: IonMonkey: MTruncateToInt32 should support constant folding
Product: Core
Classification: Components
Component: JavaScript Engine (show other bugs)
: unspecified
: All Linux
-- normal (vote)
: ---
Assigned To: general
: Jason Orendorff [:jorendorff]
Depends on:
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Reported: 2012-02-22 14:50 PST by Marty Rosenberg [:mjrosenb]
Modified: 2012-07-27 17:03 PDT (History)
1 user (show)
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/home/mrosenberg/patches/foldTruncateToInt-r0.patch (1.60 KB, patch)
2012-02-22 14:50 PST, Marty Rosenberg [:mjrosenb]
sstangl: review+
Details | Diff | Splinter Review

Description User image Marty Rosenberg [:mjrosenb] 2012-02-22 14:50:48 PST
Created attachment 599782 [details] [diff] [review]

If you have |x & 0xffffffff|, 0xffffffff is encoded as 4294967295.0 (the double), then is converted to -1 (the integer) at runtime, every time the constant is needed.

This speeds up nsieve by 11%, and md5 by 17% (on ARM)
It probably has similar benefits on x86 and x64.
Comment 1 User image Marty Rosenberg [:mjrosenb] 2012-07-27 17:03:54 PDT

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