tree def16ab5bb48af53d24479f1c9b5e8fe10e406c1
parent f9147d933ef019c7e304c19ac039f57226ce1e37
author Stephen Adams <sra@google.com> 1645226452 +0000
committer Commit Bot <commit-bot@chromium.org> 1645226452 +0000

[dart2js] GVN string concatenation

GVN pure stringifiers and string concatenation.

I removed the comment regarding #9293. I could not understand it.
Removing the 'setDependsOnSomething()' does occasionally produce
worse-looking code, but at the application level, the code is
marginally smaller.

https://github.com/dart-lang/sdk/issues/48243 is a more general
description of the 'looks better' problem that pure operations tend to
sink to their use, increasing live-ranges of the operands.  The
sinking is sometimes advantageous - e.g. when the new location is on
an error path.

I see common subexpression elimination often in the pattern of
constructing default strings for Intl.plural:


    Intl.plural(...,
        one: '$first (+$howManyMore language)',
        other: '$first (+$howManyMore languages)',
        ...);

--> old JavaScript

    var
      t1 = A.S(first) + " (+" + howManyMore + " language)",
      t2 = A.S(first) + " (+" + howManyMore + " languages)";
    return A.Intl__plural(..., t1, t2, ...);

--> new JavaScript

    var
      t1 = A.S(first) + " (+" + howManyMore;
    return A.Intl__plural(..., t1 + " language)", t1 + " languages)", ...);

Change-Id: I56aff26c9e5e31954fef224378f3723a05b318ea
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/233641
Reviewed-by: Sigmund Cherem <sigmund@google.com>
Commit-Queue: Stephen Adams <sra@google.com>