[Webkit-unassigned] [Bug 145366] FTL is not working on Windows.

[bugzilla-daemon at webkit.org]

https://bugs.webkit.org/show_bug.cgi?id=145366

--- Comment #5 from Filip Pizlo <fpizlo at apple.com> ---
(In reply to comment #4)
> (In reply to comment #3)
> > Comment on attachment 253683 [details]
> > Patch
> > 
> > View in context:
> > https://bugs.webkit.org/attachment.cgi?id=253683&action=review
> > 
> > > Source/JavaScriptCore/ChangeLog:29
> > > +        (JSC::FTL::canCompile): llvm does not support ArithPow on Windows.
> > 
> > This is the wrong approach. You're preventing the compilation of an entire
> > function because of an intrinsic. Instead you should implement ArithPow on
> > Windows using a function call to a helper.
> 
> Ok, thanks for reviewing :) I will look into this.

Note that you could literally call the pow() function.  It's possible that if you emit a call to an extern function named "pow" then LLVM might try to turn this into an intrinsic and then fail in the backend if the intrinsic is unsupported (I don't know if this is happening here, but I remember such a LLVM JIT bug with other math functions).  One way to avoid this bug is to grab a pointer to the pow() function, and then emit a call to that pointer constant.  We've done this a lot in other such thorny cases.

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