Commit baecb7d55c692a93a29a46939029b8262174ca62
2020-03-14T21:40:58
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>