[Bug target/61193] ABI incompatibility between POWER and Z HTM builtins and intrinsics

[bergner at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61193

Peter Bergner <bergner at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2014-05-16
           Assignee|unassigned at gcc dot gnu.org      |bergner at gcc dot 
gnu.org
     Ever confirmed|0                           |1

--- Comment #4 from Peter Bergner <bergner at gcc dot gnu.org> ---
After discussing this with the XL compiler team, the S390 GCC team and
the Power GCC team, we have decided to leave the incompatibility between
Power and S390.  However, the XL and GCC compilers will be compatible
with each other when targeting the same processor target.  To mitigate
the incompatibility somewhat, we have decided to add a macro to the
powerpc*-linux's htmintrin.h file that defines what the "sucessful"
return status value of the __TM_simple_begin() and __TM_begin() intrinsic
function is.  This macro is already defined in the S390's htmintrin.h
header file and is used by the S390 to determine whether the transaction
was successfully started or not.  By adding the same macro on Power, we
allow users to write common code between Power and S390, even though our
successful return status values are different.

For example, the following code can be used on Power and S390, even
though the actual value returned by __TM_simple_begin() is different.

  if ((tx_state = __TM_simple_begin ()) == _HTM_TBEGIN_STARTED)
    {
      /* Transaction State Initiated.  */
      ...
    }
  else
    {
      /* Transaction State Failed.  */
      ...
    }