[turbofan] Mark arm64 cbz/cbnz tbz/tbnz instructions as branch instructions. (issue 798553002 by baptiste.afsa@arm.com)

[baptis...@arm.com]

Reviewers: Benedikt Meurer,

Message:
PTAL

It improves performance on asm.js life and skinning benchmarks.


Description:
[turbofan] Mark arm64 cbz/cbnz tbz/tbnz instructions as branch instructions.

The instruction selector now selects pseudo instructions: CompareAndBranch
or
TestAndBranch which are associated with their continuations so that generic
code in the code generator will treat them as branch instruction and will be
able to apply optimization like avoiding branches when the code can
falltrhough.

R=bme...@chromium.org

Please review this at https://codereview.chromium.org/798553002/

Base URL: https://chromium.googlesource.com/v8/v8.git@master

Affected files (+127, -109 lines):
M src/compiler/arm64/code-generator-arm64.cc
M src/compiler/arm64/instruction-codes-arm64.h
M src/compiler/arm64/instruction-selector-arm64.cc
M test/unittests/compiler/arm64/instruction-selector-arm64-unittest.cc

[bme...@chromium.org]

LGTM

https://codereview.chromium.org/798553002/

[commi...@chromium.org]

CQ is trying da patch. Follow status at
https://chromium-cq-status.appspot.com/patch-status/798553002/1


https://codereview.chromium.org/798553002/

[commi...@chromium.org]

Committed patchset #1 (id:1)

https://codereview.chromium.org/798553002/