On Fri, Nov 21, 2025 at 9:45 AM Greg Burd <[email protected]> wrote: > Dave and I have been working together to get ARM64 with MSVC functional. > The attached patches accomplish that. Dave is the author of the first > which addresses some build issues and fixes the spin_delay() semantics, > I did the second which fixes some atomics in this combination.
A couple of immediate thoughts: https://learn.microsoft.com/en-us/cpp/intrinsics/interlockedexchangeadd-intrinsic-functions?view=msvc-170 Doesn't seem to match your conclusion. + if cc.get_id() == 'msvc' + cdata.set('USE_ARMV8_CRC32C', false) + cdata.set('USE_ARMV8_CRC32C_WITH_RUNTIME_CHECK', 1) USE_ARMV8_CRC32C_WITH_RUNTIME_CHECK (pg_crc32c_armv8_choose.c) won't actually work on Windows, but I don't think we should waste time implementing it: vendor-supported versions of Windows 11 require ARMv8.1A to boot[1][2], and that has it, so I think we should probably just define USE_ARMV8_CRC32C. +static __forceinline void +spin_delay(void) +{ + /* Reference: https://learn.microsoft.com/en-us/cpp/intrinsics/arm64-intrinsics#BarrierRestrictions */ + __isb(_ARM64_BARRIER_SY); +} I don't doubt that barriers are missing in a few places, but how can this be the right place? If you have an environment set up so it's easy to test, I would also be very interested to know if my patch set[3] that nukes all this stuff and includes <stdatomic.h> instead, which is green on Windows/x86 CI, will just work™ there too. [1] https://en.wikipedia.org/wiki/Windows_11_version_history [2] https://learn.microsoft.com/en-us/lifecycle/products/windows-11-home-and-pro [3] https://www.postgresql.org/message-id/flat/CA%2BhUKGKFvu3zyvv3aaj5hHs9VtWcjFAmisOwOc7aOZNc5AF3NA%40mail.gmail.com
