| commit | 3145befb3db608599c7ba6fd2e06917dc312305d | [log] [tgz] |
|---|---|---|
| author | zhengxing.li <zhengxing.li@intel.com> | Tue Oct 18 03:40:02 2016 |
| committer | Commit bot <commit-bot@chromium.org> | Tue Oct 18 03:40:37 2016 |
| tree | a9451a3a3e0bee4077cb0b8a84c592fd418df220 | |
| parent | cc07613674fc0c6a0044b02bd1ec483ff5d5b2bb [diff] |
[turbofan][X64] Movzxbl/Movsxbl/Movzxwl/Movsxwl also zero extend to 64bit. movzxbl/movsxbl/movzxwl/movsxwl operations implicitly zero-extend to 64-bit on x64, So It's not necessary to generate a "movl" instruction to zero-extend. For example, movzxbl/movl instruction sequence occurs frequently in v8 interpreter bytecode handler. such as: kind = BYTECODE_HANDLER name = LdaSmi compiler = turbofan Instructions (size = 76) 0x184870a3ce40 0 430fbe442601 movsxbl rax,[r14+r12*1+0x1] 0x184870a3ce46 6 48c1e020 REX.W shlq rax, 32 0x184870a3ce4a 10 498d5c2402 REX.W leaq rbx,[r12+0x2] 0x184870a3ce4f 15 420fb61433 movzxbl rdx,[rbx+r14*1] 0x184870a3ce54 20 8bd2 movl rdx,rdx <---------------------- here is a redundant "movl" 0x184870a3ce56 22 4883fa1e REX.W cmpq rdx,0x1e 0x184870a3ce5a 26 0f8518000000 jnz 56 (0x184870a3ce78) This CL also referenced to CL #36038 (https://codereview.chromium.org/1950013003 ) for adding test cases. BUG= Review-Url: https://codereview.chromium.org/2427483002 Cr-Commit-Position: refs/heads/master@{#40375}
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://github.com/v8/v8/wiki
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/*
Please follow the instructions mentioned on the V8 wiki.