Bug 256569

Summary:	Fix signed division bias for power-of-two divisor in BBQ JIT
Product:	WebKit	Reporter:	David Degazio <d_degazio>
Component:	WebAssembly	Assignee:	David Degazio <d_degazio>
Status:	RESOLVED FIXED
Severity:	Normal	CC:	mark.lam, webkit-bug-importer
Priority:	P2	Keywords:	InRadar
Version:	WebKit Nightly Build
Hardware:	Unspecified
OS:	Unspecified

Description David Degazio 2023-05-09 18:58:45 PDT

rdar://108073980

BBQ JIT currently has special instruction selection when dividing by a power of two - it'll try and use a mask or a shift. However, these operations need a bit of extra help if the dividend is a negative integer, and the current implementation is incorrect, sometimes yielding incorrect results.

Comment 1 David Degazio 2023-05-10 09:59:34 PDT

Pull request: https://github.com/WebKit/WebKit/pull/13698

Comment 2 EWS 2023-05-10 12:50:21 PDT

Committed 263925@main (acb670a0a6d0): <https://commits.webkit.org/263925@main>

Reviewed commits have been landed. Closing PR #13698 and removing active labels.