[llvm-bugs] [Bug 45176] New: [ms] wrong calling convention for member functions returning simd types in 64-bit

[via llvm-bugs]

https://bugs.llvm.org/show_bug.cgi?id=45176

            Bug ID: 45176
           Summary: [ms] wrong calling convention for member functions
                    returning simd types in 64-bit
           Product: clang
           Version: unspecified
          Hardware: PC
                OS: Windows NT
            Status: NEW
          Severity: enhancement
          Priority: P
         Component: LLVM Codegen
          Assignee: unassignedclangbugs at nondot.org
          Reporter: nicolasweber at gmx.de
                CC: llvm-bugs at lists.llvm.org, neeilans at live.com,
                    richard-llvm at metafoo.co.uk

Callee side:
https://godbolt.org/z/5uyPBD
Looks like rdx contains the address of the return buffer before the call, and
rax contains the address of where the data was written after the call.


Calling side:
https://godbolt.org/z/_FMkTv
Both f and g tailcall in clang, but only g does in MSVC -- f copies off the
stack first.


(reported here: https://twitter.com/_xalri/status/1237690440050249733 ; I
tweaked the flags a bit to pass an msvc --target)


See also
https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention?view=vs-2019
(ctrl-f __m128)

-- 
You are receiving this mail because:
You are on the CC list for the bug.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.llvm.org/pipermail/llvm-bugs/attachments/20200311/3c4b27ec/attachment.html>