[LLVMdev] FD_ZERO unsupported inline asm on 64 bit

[Cristian Zamfir]

Hello,

I get this error when compiling this code with llvm-gcc:
error: unsupported inline asm: input constraint with a matching output constraint of incompatible type!

#include <stdio.h>
#include <stdlib.h>
#include <sys/time.h>
#include <sys/types.h>
#include <unistd.h>

int 
main(void)
{                                                                                                                                                                                                                         
	fd_set rfds;                                                                                                                                                                                                                            
	FD_ZERO(&rfds);   //this is the error line
	return 0;                                                                                                                                                                                                                               
}

I used llvm-2.6 compiled from source and the latest llvm-gcc binaries for Linux x86_64. 
This code worked just fine with older versions of llvm-gcc on 32 bit Linux. 

FD_ZERO is defined in /usr/include/bits/select.h like this:

# if __WORDSIZE == 64
#  define __FD_ZERO_STOS "stosq"
#  define __FD_SET_BTS "btsq"
#  define __FD_CLR_BTR "btrq"
#  define __FD_ISSET_BT "btq"
# else
#  define __FD_ZERO_STOS "stosl"
#  define __FD_SET_BTS "btsl"
#  define __FD_CLR_BTR "btrl"
#  define __FD_ISSET_BT "btl"
# endif

# define __FD_ZERO(fdsp) \
  do {                                                                        \
    int __d0, __d1;                                                           \
    __asm__ __volatile__ ("cld; rep; " __FD_ZERO_STOS                         \
                          : "=c" (__d0), "=D" (__d1)                          \
                          : "a" (0), "0" (sizeof (fd_set)                     \
                                          / sizeof (__fd_mask)),              \
                            "1" (&__FDS_BITS (fdsp)[0])                       \
                          : "memory");                                        \
  } while (0)

Thanks, 
Cristi