[Bug target/107727] error: multiversioning needs 'ifunc' which is not supported on this target (x86_64-w64-mingw32 target)

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107727

--- Comment #3 from Andrew Pinski  ---
What they do is basically have the resolver always called:
callq   __cpu_indicator_init
movl__cpu_model+12(%rip), %eax
andl$1024, %eax # imm = 0x400
cmpl$1024, %eax # imm = 0x400
sete%al
andb$1, %al
testb   $1, %al
jne .LBB1_1
jmp .LBB1_2
.LBB1_1:
addq$40, %rsp
jmp _Z3foov.avx2# TAILCALL
.LBB1_2:
nop
addq$40, %rsp
jmp _Z3foov # TAILCALL

Not the fastest way of implementing this either.
A faster way to caching the result of the resolver.

Anyways we currently don't support multiversioning for non-ifuncs supported
targets. Someone will need to program up that support but it might be years
unless you pay someone to do it.

[Bug target/107727] error: multiversioning needs 'ifunc' which is not supported on this target (x86_64-w64-mingw32 target)

[unlvsur at live dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107727

--- Comment #2 from cqwrteur  ---
BTW. how could i detect this feature being available? I think

#if __has_cpp_attribute(__gnu__::__target__)

#endif

should not be true on targets that do not support it.

[Bug target/107727] error: multiversioning needs 'ifunc' which is not supported on this target (x86_64-w64-mingw32 target)

[unlvsur at live dot com via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=107727

--- Comment #1 from cqwrteur  ---
Here is how clang deals with it on x86_64-windows-gnu (it is how clang calls
x86_64-w64-mingw32)

https://godbolt.org/z/z5cexGEMK