Commit 31e36a6313457e32bcb7da0a85ed5a73504dd231
2020-03-14T21:40:58
Reland "Refactor BitCount" This is a reland of baecb7d55c692a93a29a46939029b8262174ca62 Directly use NEON instructions on ARM/ARM64 on MSVC. Original change's description: > Refactor BitCount > > POPCNT intrinsics cannot be used without hardware support, so a CPUID > check and polyfills are required for some CPUs when using MSVC to > avoid runtime failure. > > Other changes include: > - Clang: use builtins on all platforms to provide exact intent to the > compiler; > - MSVC on ARM: use dedicated intrinsics; > - x86/x64 fallback is now branchless and works in constant time. > > Bug: angleproject:4462 > Change-Id: I00fcabda1c842677d8cb4bfd280d932d0d10c0a5 > Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2102811 > Reviewed-by: Jamie Madill <jmadill@chromium.org> > Reviewed-by: Geoff Lang <geofflang@chromium.org> > Commit-Queue: Geoff Lang <geofflang@chromium.org> Bug: angleproject:4462 Change-Id: Ia58ae00fa4230f77d981d4ba393fa3481806c5b0 Reviewed-on: https://chromium-review.googlesource.com/c/angle/angle/+/2113570 Reviewed-by: Jamie Madill <jmadill@chromium.org> Commit-Queue: Jamie Madill <jmadill@chromium.org>