commit 2dee109437f53110fd5913050c0be100e56e5298
author Ömer Sinan Ağacan <omersa@google.com> Tue Jul 02 08:54:00 2024 +0000
committer dart-internal-monorepo <dart-internal-monorepo@dart-ci-internal.iam.gserviceaccount.com> Tue Jul 02 01:56:31 2024 -0700
tree fc7ff86a0b5650ea06de7dfedaf8f4a1fac19b3b
parent 7a0a397b7181a78071edeae7273361185100c21f

Reland "[dart2wasm] Use single unsigned cmp instead of two cmps when possible"

This is a reland of commit 8b1aa1860f1c9ca0e59530576680a0b13b3f3400

This relands the commit with the following changes to avoid regressions
and some random changes:

- Add inline annotations to `IntToWasmInt` extensions.

  These methods are 3 instructions long and often become just one
  instruction when inlined, but wasm-opt still doesn't inline them,
  turning a single `i64.lt_u` and similar into a function call.

- Revert changes from `length.leU(index)` to `index.geU(length)`.

  I had done this change because I find `if (index >= length) throw`
  easier to read than `if (length <= index) throw`, but the change
  introduced some larger changes in the wasm-opt output. These changes
  are probably harmless, but to minimize unintentional changes I
  reverted these changes for now.

Original change's description:
> [dart2wasm] Use single unsigned cmp instead of two cmps when possible
>
> wasm-opt doesn't optimize `0 < x || x > y` when y is known to be
> positive (e.g. a positive integer constant), so we do it manually.
>
> We also do it in a few places where `y` is not known to be positive in
> the Wasm code, but we know it's always positive, for example when it's a
> length.
>
> Example improvement in the wasm-opt output:
>
> ```
>    (func $_newArrayLengthCheck (;426;) (param $var0 i64) (result i64)
>      local.get $var0
>      i64.const 2147483647
> -    i64.le_s
> -    local.get $var0
> -    i64.const 0
> -    i64.ge_s
> -    i32.and
> -    i32.eqz
> +    i64.gt_u
>      if
>        i32.const 46
>        i32.const 0
> @@ -19190,13 +19172,8 @@
>                i64.const 97
>                i64.sub
>                local.tee $var3
> -              i64.const 0
> -              i64.ge_s
> -              local.get $var3
>                i64.const 5
> -              i64.le_s
> -              i32.and
> -              i32.eqz
> +              i64.gt_u
>                if
>                  local.get $var0
>                  local.get $var6
> @@ -19810,10 +19787,10 @@
>      global.get $global4
>      array.new_fixed $Array<_Type> 2
>    )
> ```
>
> Closes #56083.
>
> Change-Id: Idb1dd0d0809b26be8aec3d082aa341c59e1a353d
> Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/373663
> Reviewed-by: Martin Kustermann <kustermann@google.com>
> Commit-Queue: Ömer Ağacan <omersa@google.com>

Change-Id: I822ca612e5c8d5d33ba443107b72e9f1021c5c4a
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/374000
Reviewed-by: Martin Kustermann <kustermann@google.com>
Commit-Queue: Ömer Ağacan <omersa@google.com>

https://dart.googlesource.com/sdk/+/586c5f3b5422ddd728a4f4317db36222dfd060f1