010fcac11e
For getting from one SIMD "sibling" register to the other, the mid tier
register allocator was relying on the indexes of the two registers to be
{2N} and {2N+1}. This is only true for lower SIMD registers; later
registers can be at {2N-1} and {2N} instead, because of holes in the
allocatable double registers (e.g. d13-d15 are not allocatable currently
on ARM).
We can rely on other facts though:
1) The two aliasing registers are always successive.
2) A SIMD register code always maps to the lower register index.
3) We can get from an F32 register code to F64 and from F64 to S128 by
shifting one bit to the right (this is what
{RegisterConfiguration::GetAliases} uses).
This bug was uncovered by running the existing
cctest/test-code-generator/FuzzAssemble* tests with either
--turbo-use-mid-tier-regalloc-for-huge-functions or with
--turbo-force-mid-tier-regalloc. Hence it will be covered by these tests
once https://crrev.com/c/3347822 lands.
R=thibaudm@chromium.org
TEST=cctest/test-code-generator/FuzzAssemble*
Bug: v8:12330
Change-Id: I168840fe50b6ba6cdaa6a5462596a5cbf55c87ec
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3378782
Reviewed-by: Thibaud Michaud <thibaudm@chromium.org>
Commit-Queue: Clemens Backes <clemensb@chromium.org>
Cr-Commit-Position: refs/heads/main@{#78632}
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| docs | ||
| gni | ||
| include | ||
| infra | ||
| samples | ||
| src | ||
| test | ||
| testing | ||
| third_party | ||
| tools | ||
| .bazelrc | ||
| .clang-format | ||
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| .editorconfig | ||
| .flake8 | ||
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| .gitattributes | ||
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| .gn | ||
| .mailmap | ||
| .vpython | ||
| .vpython3 | ||
| .ycm_extra_conf.py | ||
| AUTHORS | ||
| BUILD.bazel | ||
| BUILD.gn | ||
| CODE_OF_CONDUCT.md | ||
| codereview.settings | ||
| COMMON_OWNERS | ||
| DEPS | ||
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| ENG_REVIEW_OWNERS | ||
| INFRA_OWNERS | ||
| INTL_OWNERS | ||
| LICENSE | ||
| LICENSE.fdlibm | ||
| LICENSE.strongtalk | ||
| LICENSE.v8 | ||
| LOONG_OWNERS | ||
| MIPS_OWNERS | ||
| OWNERS | ||
| PPC_OWNERS | ||
| PRESUBMIT.py | ||
| README.md | ||
| RISCV_OWNERS | ||
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V8 JavaScript Engine
V8 is Google's open source JavaScript engine.
V8 implements ECMAScript as specified in ECMA-262.
V8 is written in C++ and is used in Google Chrome, the open source browser from Google.
V8 can run standalone, or can be embedded into any C++ application.
V8 Project page: https://v8.dev/docs
Getting the Code
Checkout depot tools, and run
fetch v8
This will checkout V8 into the directory v8 and fetch all of its dependencies.
To stay up to date, run
git pull origin
gclient sync
For fetching all branches, add the following into your remote
configuration in .git/config:
fetch = +refs/branch-heads/*:refs/remotes/branch-heads/*
fetch = +refs/tags/*:refs/tags/*
Contributing
Please follow the instructions mentioned at v8.dev/docs/contribute.