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Zhi An Ng 7c98abdb78 [x64][wasm-simd] Pattern match 32x4 rotate 
Code like:

  x = wasm_v32x4_shuffle(x, x, 1, 2, 3, 0);

is currently matched by S8x16Concat, which lowers to two instructions:

  movapd xmm_dst, xmm_src
  palignr xmm_dst, xmm_src, 0x4

There is a special case after a S8x16Concat is matched:.

- is_swizzle, the inputs are the same
- it is a 32x4 shuffle (offset % 4 == 0)

Which can have a better codegen:

- (dst == src) shufps dst, src, 0b00111001
- (dst != src) pshufd dst, src, 0b00111001

Add a new simd shuffle matcher which will match 32x4 rotate, and
construct the appropriate indices referring to the 32x4 elements.

pshufd for the given example. However, this matching happens after
S8x16Concat, so we get the palignr first. We could move the pattern
matching cases around, but it will lead to some cases where
where it would have matched a S8x16Concat, but now matches a
S32x4shuffle instead, leading to worse codegen.

Note: we also pattern match on 32x4Swizzle, which correctly generates
Change-Id: Ie3aca53bbc06826be2cf49632de4c24ec73d0a9a
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2589062
Reviewed-by: Bill Budge <bbudge@chromium.org>
Commit-Queue: Zhi An Ng <zhin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71754}
2020-12-15 02:17:10 +00:00
build_overrides tracing: Enable using Perfetto client library from Chromium 2020-05-11 11:17:57 +00:00
custom_deps Use relative paths to OWNERS files 2019-08-12 13:52:52 +00:00
docs Add OWNERS for docs/ 2019-05-15 12:06:15 +00:00
gni cppgc: Fix cppgc build 2020-11-24 09:35:50 +00:00
include cppgc: Forward enum deprecation 2020-12-14 15:22:09 +00:00
infra Add new builder config for image checking 2020-12-11 13:50:31 +00:00
samples [api] Use shorter 8::Local::As<*> casts in more places 2020-11-28 11:04:26 +00:00
src [x64][wasm-simd] Pattern match 32x4 rotate 2020-12-15 02:17:10 +00:00
test [x64][wasm-simd] Pattern match 32x4 rotate 2020-12-15 02:17:10 +00:00
testing build: Remove no-op calls to set_sources_assignment_filter 2020-10-08 14:44:01 +00:00
third_party Roll inspector_protocol to 94298cef795ec994106bdaff002c41182911b767 2020-12-09 11:17:27 +00:00
tools [tools] Hide System-analyzer timeline-tracks 2020-12-14 15:10:09 +00:00
.clang-format [clang-format] Don't derive pointer alignment 2017-01-17 09:28:19 +00:00
.clang-tidy [tool] Remove unfixed clang-tidy warnings to ease use. 2018-10-26 07:40:32 +00:00
.editorconfig Add .editorconfig 2017-07-28 13:39:24 +00:00
.flake8 Add .flake8 to allow for python style checking. 2019-07-19 21:44:03 +00:00
.git-blame-ignore-revs [infra] Update .git-blame-ignore-revs 2020-03-03 12:59:13 +00:00
.gitattributes .gitattributes: Mark minified emscripten js files as -diff 2018-09-19 16:27:10 +00:00
.gitignore [gcmole] Update to LLVM 9.0.1, bootstrap from git 2020-11-16 13:05:40 +00:00
.gn [build] Dynamically decide if to use system xcode 2019-07-29 08:20:24 +00:00
.vpython [tools] Implement confidence-based number of runs 2019-05-09 09:42:28 +00:00
.ycm_extra_conf.py Fix ycm config for headers without source 2019-12-09 11:59:21 +00:00
AUTHORS Remove duplicate AUTHORS entry 2020-12-08 13:49:34 +00:00
BUILD.gn Revert "[compiler][wasm] Align Frame slots to value size" 2020-12-10 21:00:38 +00:00
CODE_OF_CONDUCT.md Explicitly state that the Chromium Code of Conduct also applies to V8 2016-03-02 09:51:24 +00:00
codereview.settings Make Gerrit the default code review for V8 2017-06-30 17:37:37 +00:00
COMMON_OWNERS Adding vahl@ to the common owners to be able to handle 2020-08-21 09:04:56 +00:00
DEPS Roll test262 2020-12-15 01:37:24 +00:00
DIR_METADATA Add DIR_METADATA files to v8. 2020-10-20 22:12:28 +00:00
ENG_REVIEW_OWNERS Add eng review owners as escalation path 2019-05-15 19:12:10 +00:00
INFRA_OWNERS Add team members as owners 2020-08-18 08:29:04 +00:00
INTL_OWNERS add ftang as owner 2020-04-24 19:19:36 +00:00
LICENSE [wasm] Draft version of C/C++ Wasm API 2019-04-17 16:00:26 +00:00
LICENSE.fdlibm Add LICENSE.fdlibm for all the fdlibm imported sources. 2016-06-09 07:17:03 +00:00
LICENSE.strongtalk Add LICENSE.v8, LICENSE.strongtalk and LICENSE.valgrind to the v8 2011-02-03 07:10:06 +00:00
LICENSE.v8 Add LICENSE.v8, LICENSE.strongtalk and LICENSE.valgrind to the v8 2011-02-03 07:10:06 +00:00
MIPS_OWNERS [mips] Request to be an owner of MIPS files 2020-11-23 09:43:49 +00:00
OWNERS Add DIR_METADATA files to v8. 2020-10-20 22:12:28 +00:00
PPC_OWNERS Adding myself to relevant OWNERS files. 2020-11-02 16:37:28 +00:00
PRESUBMIT.py [tools] Format JS files in system-analyzer/ if they're unformatted 2020-11-10 11:02:32 +00:00
README.md [docs] Change links from old wiki to v8.dev 2019-03-07 12:13:30 +00:00
S390_OWNERS Adding myself to relevant OWNERS files. 2020-11-02 16:37:28 +00:00
WATCHLISTS Stop watching for API changes in WATCHLISTS 2020-04-08 07:06:45 +00:00

README.md

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.