__bswap_constant_16 not compiled when -Werror -Wsign-conversion is given (32bit LE ARM)

[Edward Jee]

Hi, may I ask a question?
I'm using gcc and glibc on 32bit LE ARM. And I found that the
following code is not compiled, if I give -Werror -Wsign-conversion
arguments to gcc.


#include <stdio.h>
#include <byteswap.h>

int main(int argc, char *argv[]) {
  unsigned short int x = 0xbeef;
  printf("bswap_16(0x%x)=0x%x\n", x, bswap_16(x));
  return 0;
}


I saw compilation error "conversion to 'unsigned int' from 'int' may
change the sign of the result".

It looks like that a similar issue has been solved for x86 by
http://sourceware.org/git/?p=glibc.git;a=commit;h=69da074d7adfab7b57004a0dea9403a928e310a5
.
But the architecture-independent bit/byteswap.h has not been modified
(I'm using that file).

Could someone tell me why this modification is not done for the
architecture-independent bit/byteswap.h ? Am I doing something wrong?

Thanks in advance.

--
Edward Hyun-koo Jee
Software Engineer, Google Inc.