[PATCH, s390, sparc, xtensa, ia64, rs6000, mips]: Unify memory_barrier patterns

[Uros Bizjak <ubizjak at gmail dot com>]

Hello!

Now that UNSPEC_VOLATILEs represent a scheduling barrier for all 
instructions, including insns with memory operands only, we can unify 
"memory_barrier" insn pattern between all targets:

- define as unspec with volatile memory operands - no need for 
unspec_volatile anymore
- remove one level of mem:BLK from (mem:BLK (mem:BLK (scratch...)) input 
operand definition
- use Pmode for scratch register

Memory barrier should now be defined as:

--cut here--
(define_expand "memory_barrier"
 [(set (match_dup 0)
   (unspec:BLK [(match_dup 0)] UNSPEC_MB))]
 ""
{
 operands[0] = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode));
 MEM_VOLATILE_P (operands[0]) = 1;
})

(define_insn "*memory_barrier"
 [(set (match_operand:BLK 0 "" "")
   (unspec:BLK [(match_dup 0)] UNSPEC_MB))]
 ""
 "mb"
 [(set_attr "type" "mb")])
--cut here--

2009-01-02  Uros Bizjak  <ubizjak@gmail.com>

   * config/s390/s390.md (UNSPEC_MB): Rename from UNSPECV_MB.
   (memory_barrier): Expand as unspec instead of unspec_volatile.
   Remove mem:BLK from insn operands.  Use Pmode scratch register.
   (*memory_barrier): Define as unspec instead of unspec_volatile.
   Use (match_dup 0) as input operand.

   * config/sparc/sparc.md (UNSPEC_MEMBAR): Rename from UNSPECV_MEMBAR.
   * config/sparc/sync.md (memory_barrier): Expand as unspec instead of
   unspec_volatile.  Remove mem:BLK from insn operands.  Use Pmode
   scratch register.  Remove operand 1.
   (*stbar): Define as unspec instead of unspec_volatile.
   Use (match_dup 0) as input operand, remove (const_int 8).
   (*membar): Define as unspec instead of unspec_volatile.
   Use (match_dup 0) as input operand, remove input operand 2.

   * config/xtensa/xtensa.md (UNSPEC_MEMW): Rename from UNSPECV_MEMW.
   (memory_barrier): Expand as unspec instead of unspec_volatile.
   Remove mem:BLK from insn operands.  Use Pmode scratch register.
   (*memory_barrier): Define as unspec instead of unspec_volatile.
   Use (match_dup 0) as input operand.

   * config/ia64/sync.md (memory_barrier): Redefine as expander pattern.
   Remove mem:BLK from insn operands.  Use Pmode scratch register.
   Set volatile flag on operand 0.
   (*memory_barrier): New insn pattern.

   * config/rs6000/sync.md (memory_barrier): Remove mem:BLK from
   insn operands.
   (*memory_barrier): Use (match_dup 0) as input operand.

   * config/mips/sync.md (memory_barrier): Redefine as expander pattern.
   Remove mem:BLK from insn operands.  Use Pmode scratch register.
   Set volatile flag on operand 0.
   (*memory_barrier): New insn pattern.

   * config/alpha/sync.md (*memory_barrier): Rename from *mb_internal.

Patch was compile tested on all affected targets. Unless target 
maintainers have objections, I plan to commit this patch as obvious in a 
couple of days.

Uros.