Convert negative zero in ArraySpeciesCreate

Convert negative zero in ArraySpeciesCreate

As per the ES2015 spec, the value `-0` should be converted to `+0` prior
to invocation of the species constructor.

BUG=v8:4988
LOG=N
R=littledan@chromium.org

Committed: https://crrev.com/915ec67cc62edac4abbba6033e9e88f4f395d14f
Cr-Commit-Position: refs/heads/master@{#36045}

[Dan Ehrenberg, 2016-05-04 16:44:48]

https://codereview.chromium.org/1950073002/diff/1/src/js/array.js
File src/js/array.js (right):

https://codereview.chromium.org/1950073002/diff/1/src/js/array.js#newcode49
src/js/array.js:49: }
A likely faster way to convert -0 to +0 is length += 0. This is done in
InnerArrayIndexOf, for example. Maybe we should add a macro which implements it.

[mike3, 2016-05-04 16:57:22]

On 2016/05/04 16:44:48, Dan Ehrenberg wrote:
> https://codereview.chromium.org/1950073002/diff/1/src/js/array.js
> File src/js/array.js (right):
> 
> https://codereview.chromium.org/1950073002/diff/1/src/js/array.js#newcode49
> src/js/array.js:49: }
> A likely faster way to convert -0 to +0 is length += 0. This is done in
> InnerArrayIndexOf, for example. Maybe we should add a macro which implements
it.

Interesting! I'll implement that macro and re-use from InnerArrayIndexOf. Would
you like the conversion to take place unconditionally?

[Dan Ehrenberg, 2016-05-04 17:14:06]

On 2016/05/04 at 16:57:22, mike wrote:
> On 2016/05/04 16:44:48, Dan Ehrenberg wrote:
> > https://codereview.chromium.org/1950073002/diff/1/src/js/array.js
> > File src/js/array.js (right):
> > 
> > https://codereview.chromium.org/1950073002/diff/1/src/js/array.js#newcode49
> > src/js/array.js:49: }
> > A likely faster way to convert -0 to +0 is length += 0. This is done in
> > InnerArrayIndexOf, for example. Maybe we should add a macro which implements
it.
> 
> Interesting! I'll implement that macro and re-use from InnerArrayIndexOf.
Would
> you like the conversion to take place unconditionally?

You mean the way InnerArrayIndexOf does it? I think that's a good idea.

[mike3, 2016-05-04 17:27:10]

On 2016/05/04 17:14:06, Dan Ehrenberg wrote:
> On 2016/05/04 at 16:57:22, mike wrote:
> > On 2016/05/04 16:44:48, Dan Ehrenberg wrote:
> > > https://codereview.chromium.org/1950073002/diff/1/src/js/array.js
> > > File src/js/array.js (right):
> > > 
> > >
https://codereview.chromium.org/1950073002/diff/1/src/js/array.js#newcode49
> > > src/js/array.js:49: }
> > > A likely faster way to convert -0 to +0 is length += 0. This is done in
> > > InnerArrayIndexOf, for example. Maybe we should add a macro which
implements
> it.
> > 
> > Interesting! I'll implement that macro and re-use from InnerArrayIndexOf.
> Would
> > you like the conversion to take place unconditionally?
> 
> You mean the way InnerArrayIndexOf does it? I think that's a good idea.

Got it. I've just uploaded a patch to this effect. "INVERT_NEG_ZERO" is a bit of
a
mouthful, though ("TO_NEG_ZERO" was my first choice, but it's a little
inaccurate)

[Dan Ehrenberg, 2016-05-04 17:52:25]

Name bikeshedding: TO_POSITIVE_ZERO?

https://codereview.chromium.org/1950073002/diff/20001/src/js/array.js
File src/js/array.js (right):

https://codereview.chromium.org/1950073002/diff/20001/src/js/array.js#newcode...
src/js/array.js:1261: index = TO_INTEGER(index) + 0;  // Add 0 to convert -0 to
0
Also call the macro from here

[mike3, 2016-05-04 18:01:38]

On 2016/05/04 17:52:25, Dan Ehrenberg wrote:
> Name bikeshedding: TO_POSITIVE_ZERO?
> 
> https://codereview.chromium.org/1950073002/diff/20001/src/js/array.js
> File src/js/array.js (right):
> 
>
https://codereview.chromium.org/1950073002/diff/20001/src/js/array.js#newcode...
> src/js/array.js:1261: index = TO_INTEGER(index) + 0;  // Add 0 to convert -0
to
> 0
> Also call the macro from here

Apologies: I mistyped my previous response. "TO_POS_ZERO" is the name I
considered "inaccurate" because it does not convert most values to positive
zero. I don't think anyone would really suspect a macro to simply return
positive zero for all input, though.

TO_POS_ZERO, TO_POSITIVE_ZERO, INVERT_NEGATIVE_ZERO--take your pick :)

[Dan Ehrenberg, 2016-05-04 20:40:57]

lgtm

[Dan Ehrenberg, 2016-05-04 20:41:12]

On 2016/05/04 at 20:40:57, Dan Ehrenberg wrote:
> lgtm

Good point on the naming.

[mike3, 2016-05-04 21:03:10]

The CQ bit was checked by mike@mikepennisi.com

[commit-bot: I haz the power, 2016-05-04 21:03:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1950073002/40001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1950073002/40001

[commit-bot: I haz the power, 2016-05-04 21:32:01]

Committed patchset #3 (id:40001)

[commit-bot: I haz the power, 2016-05-04 21:34:00]

Description was changed from

==========
Convert negative zero in ArraySpeciesCreate

As per the ES2015 spec, the value `-0` should be converted to `+0` prior
to invocation of the species constructor.

BUG=v8:4988
LOG=N
R=littledan@chromium.org
==========

to

==========
Convert negative zero in ArraySpeciesCreate

As per the ES2015 spec, the value `-0` should be converted to `+0` prior
to invocation of the species constructor.

BUG=v8:4988
LOG=N
R=littledan@chromium.org

Committed: https://crrev.com/915ec67cc62edac4abbba6033e9e88f4f395d14f
Cr-Commit-Position: refs/heads/master@{#36045}
==========

[commit-bot: I haz the power, 2016-05-04 21:34:01]

Patchset 3 (id:??) landed as
https://crrev.com/915ec67cc62edac4abbba6033e9e88f4f395d14f
Cr-Commit-Position: refs/heads/master@{#36045}

[mike3, 2016-05-04 21:40:26]

On 2016/05/04 21:34:01, commit-bot: I haz the power wrote:
> Patchset 3 (id:??) landed as
> https://crrev.com/915ec67cc62edac4abbba6033e9e88f4f395d14f
> Cr-Commit-Position: refs/heads/master@{#36045}

Thanks, Dan!