| commit | 35974e2da664fdbc5678b540e2ab0c64b1bbd182 | [log] [tgz] |
|---|---|---|
| author | Benedikt Meurer <bmeurer@chromium.org> | Mon Aug 20 11:03:53 2018 |
| committer | Commit Bot <commit-bot@chromium.org> | Mon Aug 20 11:45:32 2018 |
| tree | 25a6a136f6d05e0a41f308cac964adbda58c1317 | |
| parent | 3b8fd36b81f0b48696617980d5d3a508f557faff [diff] |
[turbofan] Improve CheckedInt32Mod lowering. The CheckedInt32Mod lowering in the EffectControlLinearizer wasn't playing well with subsequent optimizations in the MachineOperatorReducer especially due to the use of Int32Mod, which introduces another (floating) diamond in the MachineOperatorReducer. Switching to Uint32Mod and explicit sign handling fixes the problem, plus we also do the mask trick in the case where the left hand side is negative now. With this change the performance on the benchmark mentioned in the bug report goes from console.timeEnd: binary, 1872.346000 console.timeEnd: modulo, 5967.464000 console.timeEnd: binary, 6006.789000 console.timeEnd: modulo, 6293.496000 console.timeEnd: binary, 5969.264000 console.timeEnd: modulo, 6291.874000 to console.timeEnd: binary, 1876.464000 console.timeEnd: modulo, 5846.643000 console.timeEnd: binary, 5962.545000 console.timeEnd: modulo, 5972.639000 console.timeEnd: binary, 5958.221000 console.timeEnd: modulo, 5973.171000 so even the peak performance of the modulus is now mostly the same as the binary bitwise and. Bug: v8:8069 Change-Id: Iaf3828fc0f6c53352367e8bf6c42534f8b13bfb3 Reviewed-on: https://chromium-review.googlesource.com/1180971 Reviewed-by: Jaroslav Sevcik <jarin@chromium.org> Commit-Queue: Benedikt Meurer <bmeurer@chromium.org> Cr-Commit-Position: refs/heads/master@{#55211}
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.