728940 - IonMonkey: Make comparisons against null/undefined fast

Status: RESOLVED FIXED

(Core :: JavaScript Engine, defect)

Description

[Jan de Mooij [:jandem]]

We need this for v8-richards and some other benchmarks.

Comment 1

[Jan de Mooij [:jandem]]

Attachment: Patch

Improves v8-richards from 2950 to 4280 points. Still slower than JM and JM+TI though.

Comment 2

[David Anderson [:dvander] - inactive, e-mail if emergency]

Comment on attachment 599133 [details] [diff] [review]
Patch

Review of attachment 599133 [details] [diff] [review]:
-----------------------------------------------------------------

::: js/src/ion/IonBuilder.cpp
@@ +2561,5 @@
> +        TypeOracle::Binary b = oracle->binaryOp(script, pc);
> +        if (IsNullOrUndefined(b.lhs))
> +            return jsop_compare_null_undefined(op, b.lhs, right, left);
> +        if (IsNullOrUndefined(b.rhs))
> +            return jsop_compare_null_undefined(op, b.rhs, left, right);

Could this code (including the arg swapping, though that could done in lowering like add+const) be moved to MCompare::infer instead?

Comment 3

[Jan de Mooij [:jandem]]

(In reply to David Anderson [:dvander] from comment #2)
> 
> Could this code (including the arg swapping, though that could done in
> lowering like add+const) be moved to MCompare::infer instead?

The problem with doing this in lowering is that we don't always know which operand is null/undefined (since it may be boxed). So I changed it to swap the arguments in MCompare::infer.

https://hg.mozilla.org/projects/ionmonkey/rev/5a04fd69aa09