1;; GCC machine description for i386 synchronization instructions.
2;; Copyright (C) 2005, 2006, 2007, 2008, 2009, 2010, 2011
3;; Free Software Foundation, Inc.
4;;
5;; This file is part of GCC.
6;;
7;; GCC is free software; you can redistribute it and/or modify
8;; it under the terms of the GNU General Public License as published by
9;; the Free Software Foundation; either version 3, or (at your option)
10;; any later version.
11;;
12;; GCC is distributed in the hope that it will be useful,
13;; but WITHOUT ANY WARRANTY; without even the implied warranty of
14;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15;; GNU General Public License for more details.
16;;
17;; You should have received a copy of the GNU General Public License
18;; along with GCC; see the file COPYING3.  If not see
19;; <http://www.gnu.org/licenses/>.
20
21(define_c_enum "unspec" [
22  UNSPEC_LFENCE
23  UNSPEC_SFENCE
24  UNSPEC_MFENCE
25  UNSPEC_MOVA	; For __atomic support
26  UNSPEC_LDA
27  UNSPEC_STA
28])
29
30(define_c_enum "unspecv" [
31  UNSPECV_CMPXCHG
32  UNSPECV_XCHG
33  UNSPECV_LOCK
34])
35
36(define_expand "sse2_lfence"
37  [(set (match_dup 0)
38	(unspec:BLK [(match_dup 0)] UNSPEC_LFENCE))]
39  "TARGET_SSE2"
40{
41  operands[0] = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode));
42  MEM_VOLATILE_P (operands[0]) = 1;
43})
44
45(define_insn "*sse2_lfence"
46  [(set (match_operand:BLK 0 "" "")
47	(unspec:BLK [(match_dup 0)] UNSPEC_LFENCE))]
48  "TARGET_SSE2"
49  "lfence"
50  [(set_attr "type" "sse")
51   (set_attr "length_address" "0")
52   (set_attr "atom_sse_attr" "lfence")
53   (set_attr "memory" "unknown")])
54
55(define_expand "sse_sfence"
56  [(set (match_dup 0)
57	(unspec:BLK [(match_dup 0)] UNSPEC_SFENCE))]
58  "TARGET_SSE || TARGET_3DNOW_A"
59{
60  operands[0] = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode));
61  MEM_VOLATILE_P (operands[0]) = 1;
62})
63
64(define_insn "*sse_sfence"
65  [(set (match_operand:BLK 0 "" "")
66	(unspec:BLK [(match_dup 0)] UNSPEC_SFENCE))]
67  "TARGET_SSE || TARGET_3DNOW_A"
68  "sfence"
69  [(set_attr "type" "sse")
70   (set_attr "length_address" "0")
71   (set_attr "atom_sse_attr" "fence")
72   (set_attr "memory" "unknown")])
73
74(define_expand "sse2_mfence"
75  [(set (match_dup 0)
76	(unspec:BLK [(match_dup 0)] UNSPEC_MFENCE))]
77  "TARGET_SSE2"
78{
79  operands[0] = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode));
80  MEM_VOLATILE_P (operands[0]) = 1;
81})
82
83(define_insn "mfence_sse2"
84  [(set (match_operand:BLK 0 "" "")
85	(unspec:BLK [(match_dup 0)] UNSPEC_MFENCE))]
86  "TARGET_64BIT || TARGET_SSE2"
87  "mfence"
88  [(set_attr "type" "sse")
89   (set_attr "length_address" "0")
90   (set_attr "atom_sse_attr" "fence")
91   (set_attr "memory" "unknown")])
92
93(define_insn "mfence_nosse"
94  [(set (match_operand:BLK 0 "" "")
95	(unspec:BLK [(match_dup 0)] UNSPEC_MFENCE))
96   (clobber (reg:CC FLAGS_REG))]
97  "!(TARGET_64BIT || TARGET_SSE2)"
98  "lock{%;} or{l}\t{$0, (%%esp)|DWORD PTR [esp], 0}"
99  [(set_attr "memory" "unknown")])
100
101(define_expand "mem_thread_fence"
102  [(match_operand:SI 0 "const_int_operand" "")]		;; model
103  ""
104{
105  /* Unless this is a SEQ_CST fence, the i386 memory model is strong
106     enough not to require barriers of any kind.  */
107  if (INTVAL (operands[0]) == MEMMODEL_SEQ_CST)
108    {
109      rtx (*mfence_insn)(rtx);
110      rtx mem;
111
112      if (TARGET_64BIT || TARGET_SSE2)
113	mfence_insn = gen_mfence_sse2;
114      else
115	mfence_insn = gen_mfence_nosse;
116
117      mem = gen_rtx_MEM (BLKmode, gen_rtx_SCRATCH (Pmode));
118      MEM_VOLATILE_P (mem) = 1;
119
120      emit_insn (mfence_insn (mem));
121    }
122  DONE;
123})
124
125;; ??? From volume 3 section 8.1.1 Guaranteed Atomic Operations,
126;; Only beginning at Pentium family processors do we get any guarantee of
127;; atomicity in aligned 64-bit quantities.  Beginning at P6, we get a
128;; guarantee for 64-bit accesses that do not cross a cacheline boundary.
129;;
130;; Note that the TARGET_CMPXCHG8B test below is a stand-in for "Pentium".
131;;
132;; Importantly, *no* processor makes atomicity guarantees for larger
133;; accesses.  In particular, there's no way to perform an atomic TImode
134;; move, despite the apparent applicability of MOVDQA et al.
135
136(define_mode_iterator ATOMIC
137   [QI HI SI
138    (DI "TARGET_64BIT || (TARGET_CMPXCHG8B && (TARGET_80387 || TARGET_SSE))")
139   ])
140
141(define_expand "atomic_load<mode>"
142  [(set (match_operand:ATOMIC 0 "register_operand" "")
143	(unspec:ATOMIC [(match_operand:ATOMIC 1 "memory_operand" "")
144			(match_operand:SI 2 "const_int_operand" "")]
145		       UNSPEC_MOVA))]
146  ""
147{
148  /* For DImode on 32-bit, we can use the FPU to perform the load.  */
149  if (<MODE>mode == DImode && !TARGET_64BIT)
150    emit_insn (gen_atomic_loaddi_fpu
151	       (operands[0], operands[1],
152	        assign_386_stack_local (DImode,
153					(virtuals_instantiated
154					 ? SLOT_TEMP : SLOT_VIRTUAL))));
155  else
156    emit_move_insn (operands[0], operands[1]);
157  DONE;
158})
159
160(define_insn_and_split "atomic_loaddi_fpu"
161  [(set (match_operand:DI 0 "nonimmediate_operand" "=x,m,?r")
162	(unspec:DI [(match_operand:DI 1 "memory_operand" "m,m,m")]
163		   UNSPEC_MOVA))
164   (clobber (match_operand:DI 2 "memory_operand" "=X,X,m"))
165   (clobber (match_scratch:DF 3 "=X,xf,xf"))]
166  "!TARGET_64BIT && (TARGET_80387 || TARGET_SSE)"
167  "#"
168  "&& reload_completed"
169  [(const_int 0)]
170{
171  rtx dst = operands[0], src = operands[1];
172  rtx mem = operands[2], tmp = operands[3];
173
174  if (SSE_REG_P (dst))
175    emit_move_insn (dst, src);
176  else
177    {
178      if (MEM_P (dst))
179	mem = dst;
180
181      if (FP_REG_P (tmp))
182        {
183	  emit_insn (gen_loaddi_via_fpu (tmp, src));
184	  emit_insn (gen_storedi_via_fpu (mem, tmp));
185	}
186      else
187	{
188	  adjust_reg_mode (tmp, DImode);
189	  emit_move_insn (tmp, src);
190	  emit_move_insn (mem, tmp);
191	}
192
193      if (mem != dst)
194	emit_move_insn (dst, mem);
195    }
196  DONE;
197})
198
199(define_expand "atomic_store<mode>"
200  [(set (match_operand:ATOMIC 0 "memory_operand" "")
201	(unspec:ATOMIC [(match_operand:ATOMIC 1 "register_operand" "")
202			(match_operand:SI 2 "const_int_operand" "")]
203		       UNSPEC_MOVA))]
204  ""
205{
206  enum memmodel model = (enum memmodel) INTVAL (operands[2]);
207
208  if (<MODE>mode == DImode && !TARGET_64BIT)
209    {
210      /* For DImode on 32-bit, we can use the FPU to perform the store.  */
211      /* Note that while we could perform a cmpxchg8b loop, that turns
212	 out to be significantly larger than this plus a barrier.  */
213      emit_insn (gen_atomic_storedi_fpu
214		 (operands[0], operands[1],
215	          assign_386_stack_local (DImode,
216					  (virtuals_instantiated
217					   ? SLOT_TEMP : SLOT_VIRTUAL))));
218    }
219  else
220    {
221      /* For seq-cst stores, when we lack MFENCE, use XCHG.  */
222      if (model == MEMMODEL_SEQ_CST && !(TARGET_64BIT || TARGET_SSE2))
223	{
224	  emit_insn (gen_atomic_exchange<mode> (gen_reg_rtx (<MODE>mode),
225						operands[0], operands[1],
226						operands[2]));
227	  DONE;
228	}
229
230      /* Otherwise use a normal store.  */
231      emit_move_insn (operands[0], operands[1]);
232    }
233  /* ... followed by an MFENCE, if required.  */
234  if (model == MEMMODEL_SEQ_CST)
235    emit_insn (gen_mem_thread_fence (operands[2]));
236  DONE;
237})
238
239(define_insn_and_split "atomic_storedi_fpu"
240  [(set (match_operand:DI 0 "memory_operand" "=m,m,m")
241	(unspec:DI [(match_operand:DI 1 "register_operand" "x,m,?r")]
242		   UNSPEC_MOVA))
243   (clobber (match_operand:DI 2 "memory_operand" "=X,X,m"))
244   (clobber (match_scratch:DF 3 "=X,xf,xf"))]
245  "!TARGET_64BIT && (TARGET_80387 || TARGET_SSE)"
246  "#"
247  "&& reload_completed"
248  [(const_int 0)]
249{
250  rtx dst = operands[0], src = operands[1];
251  rtx mem = operands[2], tmp = operands[3];
252
253  if (!SSE_REG_P (src))
254    {
255      if (REG_P (src))
256	{
257	  emit_move_insn (mem, src);
258	  src = mem;
259	}
260
261      if (FP_REG_P (tmp))
262	{
263	  emit_insn (gen_loaddi_via_fpu (tmp, src));
264	  emit_insn (gen_storedi_via_fpu (dst, tmp));
265	  DONE;
266	}
267      else
268	{
269	  adjust_reg_mode (tmp, DImode);
270	  emit_move_insn (tmp, mem);
271	  src = tmp;
272	}
273    }
274  emit_move_insn (dst, src);
275  DONE;
276})
277
278;; ??? You'd think that we'd be able to perform this via FLOAT + FIX_TRUNC
279;; operations.  But the fix_trunc patterns want way more setup than we want
280;; to provide.  Note that the scratch is DFmode instead of XFmode in order
281;; to make it easy to allocate a scratch in either SSE or FP_REGs above.
282
283(define_insn "loaddi_via_fpu"
284  [(set (match_operand:DF 0 "register_operand" "=f")
285	(unspec:DF [(match_operand:DI 1 "memory_operand" "m")] UNSPEC_LDA))]
286  "TARGET_80387"
287  "fild%Z1\t%1"
288  [(set_attr "type" "fmov")
289   (set_attr "mode" "DF")
290   (set_attr "fp_int_src" "true")])
291
292(define_insn "storedi_via_fpu"
293  [(set (match_operand:DI 0 "memory_operand" "=m")
294	(unspec:DI [(match_operand:DF 1 "register_operand" "f")] UNSPEC_STA))]
295  "TARGET_80387"
296{
297  gcc_assert (find_regno_note (insn, REG_DEAD, FIRST_STACK_REG) != NULL_RTX);
298
299  return "fistp%Z0\t%0";
300}
301  [(set_attr "type" "fmov")
302   (set_attr "mode" "DI")])
303
304(define_expand "atomic_compare_and_swap<mode>"
305  [(match_operand:QI 0 "register_operand" "")		;; bool success output
306   (match_operand:SWI124 1 "register_operand" "")	;; oldval output
307   (match_operand:SWI124 2 "memory_operand" "")		;; memory
308   (match_operand:SWI124 3 "register_operand" "")	;; expected input
309   (match_operand:SWI124 4 "register_operand" "")	;; newval input
310   (match_operand:SI 5 "const_int_operand" "")		;; is_weak
311   (match_operand:SI 6 "const_int_operand" "")		;; success model
312   (match_operand:SI 7 "const_int_operand" "")]		;; failure model
313  "TARGET_CMPXCHG"
314{
315  emit_insn
316   (gen_atomic_compare_and_swap<mode>_1
317    (operands[1], operands[2], operands[3], operands[4]));
318  ix86_expand_setcc (operands[0], EQ, gen_rtx_REG (CCZmode, FLAGS_REG),
319		     const0_rtx);
320  DONE;
321})
322
323(define_mode_iterator CASMODE
324  [(DI "TARGET_64BIT || TARGET_CMPXCHG8B")
325   (TI "TARGET_64BIT && TARGET_CMPXCHG16B")])
326(define_mode_attr CASHMODE [(DI "SI") (TI "DI")])
327
328(define_expand "atomic_compare_and_swap<mode>"
329  [(match_operand:QI 0 "register_operand" "")		;; bool success output
330   (match_operand:CASMODE 1 "register_operand" "")	;; oldval output
331   (match_operand:CASMODE 2 "memory_operand" "")	;; memory
332   (match_operand:CASMODE 3 "register_operand" "")	;; expected input
333   (match_operand:CASMODE 4 "register_operand" "")	;; newval input
334   (match_operand:SI 5 "const_int_operand" "")		;; is_weak
335   (match_operand:SI 6 "const_int_operand" "")		;; success model
336   (match_operand:SI 7 "const_int_operand" "")]		;; failure model
337  "TARGET_CMPXCHG"
338{
339  if (<MODE>mode == DImode && TARGET_64BIT)
340    {
341      emit_insn
342       (gen_atomic_compare_and_swapdi_1
343	(operands[1], operands[2], operands[3], operands[4]));
344    }
345  else
346    {
347      enum machine_mode hmode = <CASHMODE>mode;
348      rtx lo_o, lo_e, lo_n, hi_o, hi_e, hi_n, mem;
349
350      lo_o = operands[1];
351      mem  = operands[2];
352      lo_e = operands[3];
353      lo_n = operands[4];
354      hi_o = gen_highpart (hmode, lo_o);
355      hi_e = gen_highpart (hmode, lo_e);
356      hi_n = gen_highpart (hmode, lo_n);
357      lo_o = gen_lowpart (hmode, lo_o);
358      lo_e = gen_lowpart (hmode, lo_e);
359      lo_n = gen_lowpart (hmode, lo_n);
360
361      if (!cmpxchg8b_pic_memory_operand (mem, <MODE>mode))
362 	mem = replace_equiv_address (mem, force_reg (Pmode, XEXP (mem, 0)));
363
364      emit_insn
365       (gen_atomic_compare_and_swap<mode>_doubleword
366        (lo_o, hi_o, mem, lo_e, hi_e, lo_n, hi_n));
367    }
368
369  ix86_expand_setcc (operands[0], EQ, gen_rtx_REG (CCZmode, FLAGS_REG),
370		     const0_rtx);
371  DONE;
372})
373
374(define_insn "atomic_compare_and_swap<mode>_1"
375  [(set (match_operand:SWI 0 "register_operand" "=a")
376	(unspec_volatile:SWI
377	  [(match_operand:SWI 1 "memory_operand" "+m")
378	   (match_operand:SWI 2 "register_operand" "0")
379	   (match_operand:SWI 3 "register_operand" "<r>")]
380	  UNSPECV_CMPXCHG))
381   (set (match_dup 1)
382	(unspec_volatile:SWI [(const_int 0)] UNSPECV_CMPXCHG))
383   (set (reg:CCZ FLAGS_REG)
384        (unspec_volatile:CCZ [(const_int 0)] UNSPECV_CMPXCHG))]
385  "TARGET_CMPXCHG"
386  "lock{%;} cmpxchg{<imodesuffix>}\t{%3, %1|%1, %3}")
387
388;; For double-word compare and swap, we are obliged to play tricks with
389;; the input newval (op5:op6) because the Intel register numbering does
390;; not match the gcc register numbering, so the pair must be CX:BX.
391;; That said, in order to take advantage of possible lower-subreg opts,
392;; treat all of the integral operands in the same way.
393
394;; Operands 5 and 6 really need to be different registers, which in
395;; this case means op5 must not be ecx.  If op5 and op6 are the same
396;; (like when the input is -1LL) GCC might chose to allocate op5 to ecx,
397;; like op6.  This breaks, as the xchg will move the PIC register
398;; contents to %ecx then --> boom.
399
400(define_mode_attr doublemodesuffix [(SI "8") (DI "16")])
401(define_mode_attr regprefix [(SI "e") (DI "r")])
402
403(define_insn "atomic_compare_and_swap<dwi>_doubleword"
404  [(set (match_operand:DWIH 0 "register_operand" "=a,a")
405	(unspec_volatile:DWIH
406	  [(match_operand:<DWI> 2 "cmpxchg8b_pic_memory_operand" "+m,m")
407	   (match_operand:DWIH 3 "register_operand" "0,0")
408	   (match_operand:DWIH 4 "register_operand" "1,1")
409	   (match_operand:DWIH 5 "register_operand" "b,!*r")
410	   (match_operand:DWIH 6 "register_operand" "c,c")]
411	  UNSPECV_CMPXCHG))
412   (set (match_operand:DWIH 1 "register_operand" "=d,d")
413	(unspec_volatile:DWIH [(const_int 0)] UNSPECV_CMPXCHG))
414   (set (match_dup 2)
415	(unspec_volatile:<DWI> [(const_int 0)] UNSPECV_CMPXCHG))
416   (set (reg:CCZ FLAGS_REG)
417        (unspec_volatile:CCZ [(const_int 0)] UNSPECV_CMPXCHG))
418   (clobber (match_scratch:DWIH 7 "=X,&5"))]
419  "TARGET_CMPXCHG<doublemodesuffix>B"
420{
421  bool swap = REGNO (operands[5]) != BX_REG;
422
423  if (swap)
424    output_asm_insn ("xchg{<imodesuffix>}\t%%<regprefix>bx, %5", operands);
425
426  output_asm_insn ("lock{%;} cmpxchg<doublemodesuffix>b\t%2", operands);
427
428  if (swap)
429    output_asm_insn ("xchg{<imodesuffix>}\t%%<regprefix>bx, %5", operands);
430
431  return "";
432})
433
434;; For operand 2 nonmemory_operand predicate is used instead of
435;; register_operand to allow combiner to better optimize atomic
436;; additions of constants.
437(define_insn "atomic_fetch_add<mode>"
438  [(set (match_operand:SWI 0 "register_operand" "=<r>")
439	(unspec_volatile:SWI
440	  [(match_operand:SWI 1 "memory_operand" "+m")
441	   (match_operand:SI 3 "const_int_operand" "")]		;; model
442	  UNSPECV_XCHG))
443   (set (match_dup 1)
444	(plus:SWI (match_dup 1)
445		  (match_operand:SWI 2 "nonmemory_operand" "0")))
446   (clobber (reg:CC FLAGS_REG))]
447  "TARGET_XADD"
448  "lock{%;} xadd{<imodesuffix>}\t{%0, %1|%1, %0}")
449
450;; This peephole2 and following insn optimize
451;; __sync_fetch_and_add (x, -N) == N into just lock {add,sub,inc,dec}
452;; followed by testing of flags instead of lock xadd and comparisons.
453(define_peephole2
454  [(set (match_operand:SWI 0 "register_operand" "")
455	(match_operand:SWI 2 "const_int_operand" ""))
456   (parallel [(set (match_dup 0)
457		   (unspec_volatile:SWI
458		     [(match_operand:SWI 1 "memory_operand" "")
459		      (match_operand:SI 4 "const_int_operand" "")]
460		     UNSPECV_XCHG))
461	      (set (match_dup 1)
462		   (plus:SWI (match_dup 1)
463			     (match_dup 0)))
464	      (clobber (reg:CC FLAGS_REG))])
465   (set (reg:CCZ FLAGS_REG)
466	(compare:CCZ (match_dup 0)
467		     (match_operand:SWI 3 "const_int_operand" "")))]
468  "peep2_reg_dead_p (3, operands[0])
469   && (unsigned HOST_WIDE_INT) INTVAL (operands[2])
470      == -(unsigned HOST_WIDE_INT) INTVAL (operands[3])
471   && !reg_overlap_mentioned_p (operands[0], operands[1])"
472  [(parallel [(set (reg:CCZ FLAGS_REG)
473		   (compare:CCZ
474		     (unspec_volatile:SWI [(match_dup 1) (match_dup 4)]
475					  UNSPECV_XCHG)
476		     (match_dup 3)))
477	      (set (match_dup 1)
478		   (plus:SWI (match_dup 1)
479			     (match_dup 2)))])])
480
481(define_insn "*atomic_fetch_add_cmp<mode>"
482  [(set (reg:CCZ FLAGS_REG)
483	(compare:CCZ (unspec_volatile:SWI
484		       [(match_operand:SWI 0 "memory_operand" "+m")
485		        (match_operand:SI 3 "const_int_operand" "")]
486		       UNSPECV_XCHG)
487		     (match_operand:SWI 2 "const_int_operand" "i")))
488   (set (match_dup 0)
489	(plus:SWI (match_dup 0)
490		  (match_operand:SWI 1 "const_int_operand" "i")))]
491  "(unsigned HOST_WIDE_INT) INTVAL (operands[1])
492   == -(unsigned HOST_WIDE_INT) INTVAL (operands[2])"
493{
494  if (TARGET_USE_INCDEC)
495    {
496      if (operands[1] == const1_rtx)
497	return "lock{%;} inc{<imodesuffix>}\t%0";
498      if (operands[1] == constm1_rtx)
499	return "lock{%;} dec{<imodesuffix>}\t%0";
500    }
501
502  if (x86_maybe_negate_const_int (&operands[1], <MODE>mode))
503    return "lock{%;} sub{<imodesuffix>}\t{%1, %0|%0, %1}";
504
505  return "lock{%;} add{<imodesuffix>}\t{%1, %0|%0, %1}";
506})
507
508;; Recall that xchg implicitly sets LOCK#, so adding it again wastes space.
509;; In addition, it is always a full barrier, so we can ignore the memory model.
510(define_insn "atomic_exchange<mode>"
511  [(set (match_operand:SWI 0 "register_operand" "=<r>")		;; output
512	(unspec_volatile:SWI
513	  [(match_operand:SWI 1 "memory_operand" "+m")		;; memory
514	   (match_operand:SI 3 "const_int_operand" "")]		;; model
515	  UNSPECV_XCHG))
516   (set (match_dup 1)
517	(match_operand:SWI 2 "register_operand" "0"))]		;; input
518  ""
519  "xchg{<imodesuffix>}\t{%1, %0|%0, %1}")
520
521(define_insn "atomic_add<mode>"
522  [(set (match_operand:SWI 0 "memory_operand" "+m")
523	(unspec_volatile:SWI
524	  [(plus:SWI (match_dup 0)
525		     (match_operand:SWI 1 "nonmemory_operand" "<r><i>"))
526	   (match_operand:SI 2 "const_int_operand" "")]		;; model
527	  UNSPECV_LOCK))
528   (clobber (reg:CC FLAGS_REG))]
529  ""
530{
531  if (TARGET_USE_INCDEC)
532    {
533      if (operands[1] == const1_rtx)
534	return "lock{%;} inc{<imodesuffix>}\t%0";
535      if (operands[1] == constm1_rtx)
536	return "lock{%;} dec{<imodesuffix>}\t%0";
537    }
538
539  if (x86_maybe_negate_const_int (&operands[1], <MODE>mode))
540    return "lock{%;} sub{<imodesuffix>}\t{%1, %0|%0, %1}";
541
542  return "lock{%;} add{<imodesuffix>}\t{%1, %0|%0, %1}";
543})
544
545(define_insn "atomic_sub<mode>"
546  [(set (match_operand:SWI 0 "memory_operand" "+m")
547	(unspec_volatile:SWI
548	  [(minus:SWI (match_dup 0)
549		      (match_operand:SWI 1 "nonmemory_operand" "<r><i>"))
550	   (match_operand:SI 2 "const_int_operand" "")]		;; model
551	  UNSPECV_LOCK))
552   (clobber (reg:CC FLAGS_REG))]
553  ""
554{
555  if (TARGET_USE_INCDEC)
556    {
557      if (operands[1] == const1_rtx)
558	return "lock{%;} dec{<imodesuffix>}\t%0";
559      if (operands[1] == constm1_rtx)
560	return "lock{%;} inc{<imodesuffix>}\t%0";
561    }
562
563  if (x86_maybe_negate_const_int (&operands[1], <MODE>mode))
564    return "lock{%;} add{<imodesuffix>}\t{%1, %0|%0, %1}";
565
566  return "lock{%;} sub{<imodesuffix>}\t{%1, %0|%0, %1}";
567})
568
569(define_insn "atomic_<logic><mode>"
570  [(set (match_operand:SWI 0 "memory_operand" "+m")
571	(unspec_volatile:SWI
572	  [(any_logic:SWI (match_dup 0)
573			  (match_operand:SWI 1 "nonmemory_operand" "<r><i>"))
574	   (match_operand:SI 2 "const_int_operand" "")]		;; model
575	  UNSPECV_LOCK))
576   (clobber (reg:CC FLAGS_REG))]
577  ""
578  "lock{%;} <logic>{<imodesuffix>}\t{%1, %0|%0, %1}")
579