Description of problem:
gcc builtin function __builtin_ia32_rdrand32_step() seems to emit
cmov instruction unconditionally,even if -march=i586 (no cmov capability)
is given to gcc.


Version-Release number of selected component (if applicable):
gcc version 11.3.1 20220421 (Red Hat 11.3.1-2) (GCC)

How reproducible:
always

Steps to Reproduce:
0. install glibc-devel.i686
sudo dnf install glibc-devel.i686

1. create rdrand.c file as follows:
/* gcc -mrdrnd -march=i586 -m32 rdrand.c */
#include <stdio.h>
int main()
{
        int s,r;
        s = __builtin_ia32_rdrand32_step(&r);
        printf("rdrand=%d status=%d\n", r, s);
}

2. Compile with:
gcc -mrdrnd -march=i586 -m32 rdrand.c

3. Examine the output by objdump -d:
objdump -d a.out | grep -C 3 cmov

Actual results:
[kabe@centos-s-9 ~]$ objdump -d a.out | grep -C 3 cmov
 80491a1:       0f c7 f0                rdrand %eax
 80491a4:       89 02                   mov    %eax,(%edx)
 80491a6:       ba 01 00 00 00          mov    $0x1,%edx
 80491ab:       0f 42 c2                cmovb  %edx,%eax
 80491ae:       89 45 f4                mov    %eax,-0xc(%ebp)
 80491b1:       8b 45 f0                mov    -0x10(%ebp),%eax
 80491b4:       83 ec 04                sub    $0x4,%esp


Expected results:
no match


Additional info:
gcc generates instructions on the fly for __builtin* functions.
cmov seems to be generated by usage of gen_rtx_IF_THEN_ELSE() in rdrand_step: branch of gcc's gcc/config/i386/i386-expand.c, but I could not trace the cause why -march=i586 is not honoured by the on-the-fly compiler.