[Bug target/87344] archival/libarchive/decompress_gunzip.c:1139:2: error: size of unnamed array is negative, -mms-bitfields influences non-bitfield struct layout

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=87344

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ABI
             Target|                            |x86_64-*-*, i?86-*-*
                 CC|rguenth at gcc dot gnu.org         |
          Component|c                           |target
            Summary|archival/libarchive/decompr |archival/libarchive/decompr
                   |ess_gunzip.c:1139:2: error: |ess_gunzip.c:1139:2: error:
                   |size of unnamed array is    |size of unnamed array is
                   |negative                    |negative, -mms-bitfields
                   |                            |influences non-bitfield
                   |                            |struct layout

--- Comment #4 from Richard Biener <rguenth at gcc dot gnu.org> ---
It's -mms-bitfields which appearantly influences layout of the following
struct:

 union {
  unsigned char raw[8];
  struct {
   uint8_t gz_method;
   uint8_t flags;
   uint32_t mtime;
   uint8_t xtra_flags_UNUSED;
   uint8_t os_flags_UNUSED;
  } __attribute__ ((__packed__)) formatted;
 } header;

 ((void)sizeof(char[1 - 2*!!(sizeof(header) != 8)]));

Not sure if the difference is intended.