1 //
  2 // Copyright (c) 2018, Red Hat, Inc. All rights reserved.
  3 // DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4 //
  5 // This code is free software; you can redistribute it and/or modify it
  6 // under the terms of the GNU General Public License version 2 only, as
  7 // published by the Free Software Foundation.
  8 //
  9 // This code is distributed in the hope that it will be useful, but WITHOUT
 10 // ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11 // FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12 // version 2 for more details (a copy is included in the LICENSE file that
 13 // accompanied this code).
 14 //
 15 // You should have received a copy of the GNU General Public License version
 16 // 2 along with this work; if not, write to the Free Software Foundation,
 17 // Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18 //
 19 // Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20 // or visit www.oracle.com if you need additional information or have any
 21 // questions.
 22 //
 23 //
 24 
 25 source %{
 26 #include "gc/shenandoah/shenandoahBarrierSet.hpp"
 27 #include "gc/shenandoah/shenandoahBarrierSetAssembler_aarch64.hpp"
 28 #include "gc/shenandoah/c2/shenandoahBarrierSetC2.hpp"
 29 %}
 30 
 31 instruct store_P_Normal_shenandoah(memory8 mem, iRegP src, rFlagsReg cr)
 32 %{
 33   match(Set mem (StoreP mem src));
 34   predicate(UseShenandoahGC && !needs_releasing_store(n) && n->as_Store()->barrier_data() != 0);
 35   effect(KILL cr);
 36   ins_cost(3*INSN_COST);
 37   format %{ "str $src, $mem" %}
 38   ins_encode %{
 39     const Address addr = mem2address($mem->opcode(), as_Register($mem$$base), $mem$$index, $mem$$scale, $mem$$disp);
 40     ShenandoahBarrierSet::assembler()->store_c2(this, masm,
 41       addr,           /* dst_narrow  = */ false,
 42       $src$$Register, /* src_narrow  = */ false,
 43       /* is_volatile */ false);
 44   %}
 45   ins_pipe(pipe_class_memory);
 46 %}
 47 
 48 instruct store_P_Volatile_shenandoah(indirect mem, iRegP src, rFlagsReg cr)
 49 %{
 50   match(Set mem (StoreP mem src));
 51   predicate(UseShenandoahGC && needs_releasing_store(n) && n->as_Store()->barrier_data() != 0);
 52   effect(KILL cr);
 53   ins_cost(VOLATILE_REF_COST);
 54   format %{ "str $src, $mem" %}
 55   ins_encode %{
 56     ShenandoahBarrierSet::assembler()->store_c2(this, masm,
 57       Address($mem$$Register),    /* dst_narrow  = */ false,
 58       $src$$Register,             /* src_narrow  = */ false,
 59       /* is_volatile */ true);
 60   %}
 61   ins_pipe(pipe_class_memory);
 62 %}
 63 
 64 instruct store_N_Normal_shenandoah(memory4 mem, iRegN src, rFlagsReg cr)
 65 %{
 66   match(Set mem (StoreN mem src));
 67   predicate(UseShenandoahGC && !needs_releasing_store(n) && n->as_Store()->barrier_data() != 0);
 68   effect(KILL cr);
 69   ins_cost(3*INSN_COST);
 70   format %{ "str $src, $mem" %}
 71   ins_encode %{
 72     const Address addr = mem2address($mem->opcode(), as_Register($mem$$base), $mem$$index, $mem$$scale, $mem$$disp);
 73     ShenandoahBarrierSet::assembler()->store_c2(this, masm,
 74       addr,           /* dst_narrow  = */ true,
 75       $src$$Register, /* src_narrow  = */ true,
 76       /* is_volatile */ false);
 77   %}
 78   ins_pipe(pipe_class_memory);
 79 %}
 80 
 81 instruct store_N_Volatile_shenandoah(indirect mem, iRegN src, rFlagsReg cr)
 82 %{
 83   match(Set mem (StoreN mem src));
 84   predicate(UseShenandoahGC && needs_releasing_store(n) && n->as_Store()->barrier_data() != 0);
 85   effect(KILL cr);
 86   ins_cost(VOLATILE_REF_COST);
 87   format %{ "str $src, $mem" %}
 88   ins_encode %{
 89     ShenandoahBarrierSet::assembler()->store_c2(this, masm,
 90       Address($mem$$Register),    /* dst_narrow  = */ true,
 91       $src$$Register,             /* src_narrow  = */ true,
 92       /* is_volatile */ true);
 93   %}
 94   ins_pipe(pipe_class_memory);
 95 %}
 96 
 97 instruct encodePAndStoreN_Normal_shenandoah(memory4 mem, iRegP src, rFlagsReg cr)
 98 %{
 99   match(Set mem (StoreN mem (EncodeP src)));
100   predicate(UseShenandoahGC && !needs_releasing_store(n) && n->as_Store()->barrier_data() != 0);
101   effect(KILL cr);
102   ins_cost(4*INSN_COST);
103   format %{ "encode_heap_oop tmp, $src\n\t"
104             "str  tmp, $mem\t# compressed ptr" %}
105   ins_encode %{
106     const Address addr = mem2address($mem->opcode(), as_Register($mem$$base), $mem$$index, $mem$$scale, $mem$$disp);
107     ShenandoahBarrierSet::assembler()->store_c2(this, masm,
108       addr,                    /* dst_narrow  = */ true,
109       $src$$Register,          /* src_narrow  = */ false,
110       /* is_volatile */ false);
111   %}
112   ins_pipe(pipe_class_memory);
113 %}
114 
115 instruct encodePAndStoreN_Volatile_shenandoah(indirect mem, iRegP src, rFlagsReg cr)
116 %{
117   match(Set mem (StoreN mem (EncodeP src)));
118   predicate(UseShenandoahGC && needs_releasing_store(n) && n->as_Store()->barrier_data() != 0);
119   effect(KILL cr);
120   ins_cost(4*INSN_COST);
121   format %{ "encode_heap_oop tmp, $src\n\t"
122             "str  tmp, $mem\t# compressed ptr" %}
123   ins_encode %{
124     ShenandoahBarrierSet::assembler()->store_c2(this, masm,
125       Address($mem$$Register), /* dst_narrow  = */ true,
126       $src$$Register,          /* src_narrow  = */ false,
127       /* is_volatile */ true);
128   %}
129   ins_pipe(pipe_class_memory);
130 %}
131 
132 instruct compareAndSwap_P_shenandoah(iRegINoSp res, indirect mem, iRegPNoSp oldval, iRegP newval, rFlagsReg cr)
133 %{
134   match(Set res (CompareAndSwapP mem (Binary oldval newval)));
135   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
136   ins_cost(VOLATILE_REF_COST);
137   effect(TEMP_DEF res, KILL cr);
138   format %{
139     "cmpxchg_P_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
140   %}
141   ins_encode %{
142     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
143 
144     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
145       $res$$Register,
146       $mem$$base$$Register,
147       $oldval$$Register,
148       $newval$$Register,
149       /* exchange */ false,
150       /* is_narrow */ false,
151       /* weak */ false,
152       /* acquire */ false);
153   %}
154 
155   ins_pipe(pipe_slow);
156 %}
157 
158 instruct compareAndSwap_P_A_shenandoah(iRegINoSp res, indirect mem, iRegPNoSp oldval, iRegP newval, rFlagsReg cr)
159 %{
160   match(Set res (CompareAndSwapP mem (Binary oldval newval)));
161   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
162   ins_cost(VOLATILE_REF_COST);
163   effect(TEMP_DEF res, KILL cr);
164   format %{
165     "cmpxchg_P_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
166   %}
167   ins_encode %{
168     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
169 
170     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
171       $res$$Register,
172       $mem$$base$$Register,
173       $oldval$$Register,
174       $newval$$Register,
175       /* exchange */ false,
176       /* is_narrow */ false,
177       /* weak */ false,
178       /* acquire */ true);
179   %}
180 
181   ins_pipe(pipe_slow);
182 %}
183 
184 instruct compareAndSwap_N_shenandoah(iRegINoSp res, indirect mem, iRegNNoSp oldval, iRegN newval, rFlagsReg cr)
185 %{
186   match(Set res (CompareAndSwapN mem (Binary oldval newval)));
187   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
188   ins_cost(VOLATILE_REF_COST);
189   effect(TEMP_DEF res, KILL cr);
190   format %{
191     "cmpxchg_N_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
192   %}
193   ins_encode %{
194     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
195 
196     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
197       $res$$Register,
198       $mem$$base$$Register,
199       $oldval$$Register,
200       $newval$$Register,
201       /* exchange */ false,
202       /* is_narrow */ true,
203       /* weak */ false,
204       /* acquire */ false);
205   %}
206 
207   ins_pipe(pipe_slow);
208 %}
209 
210 instruct compareAndSwap_N_A_shenandoah(iRegINoSp res, indirect mem, iRegNNoSp oldval, iRegN newval, rFlagsReg cr)
211 %{
212   match(Set res (CompareAndSwapN mem (Binary oldval newval)));
213   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
214   ins_cost(VOLATILE_REF_COST);
215   effect(TEMP_DEF res, KILL cr);
216   format %{
217     "cmpxchg_N_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
218   %}
219   ins_encode %{
220     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
221 
222     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
223       $res$$Register,
224       $mem$$base$$Register,
225       $oldval$$Register,
226       $newval$$Register,
227       /* exchange */ false,
228       /* is_narrow */ true,
229       /* weak */ false,
230       /* acquire */ true);
231   %}
232 
233   ins_pipe(pipe_slow);
234 %}
235 
236 instruct compareAndExchange_N_shenandoah(iRegNNoSp res, indirect mem, iRegN oldval, iRegN newval, rFlagsReg cr)
237 %{
238   match(Set res (CompareAndExchangeN mem (Binary oldval newval)));
239   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
240   ins_cost(2*VOLATILE_REF_COST);
241   effect(TEMP_DEF res, KILL cr);
242   format %{
243     "cae_N_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
244   %}
245   ins_encode %{
246     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
247 
248     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
249       $res$$Register,
250       $mem$$base$$Register,
251       $oldval$$Register,
252       $newval$$Register,
253       /* exchange */ true,
254       /* is_narrow */ true,
255       /* weak */ false,
256       /* acquire */ false);
257   %}
258   ins_pipe(pipe_slow);
259 %}
260 
261 instruct compareAndExchange_N_A_shenandoah(iRegNNoSp res, indirect mem, iRegN oldval, iRegN newval, rFlagsReg cr)
262 %{
263   match(Set res (CompareAndExchangeN mem (Binary oldval newval)));
264   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
265   ins_cost(2*VOLATILE_REF_COST);
266   effect(TEMP_DEF res, KILL cr);
267   format %{
268     "cae_N_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
269   %}
270   ins_encode %{
271     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
272 
273     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
274       $res$$Register,
275       $mem$$base$$Register,
276       $oldval$$Register,
277       $newval$$Register,
278       /* exchange */ true,
279       /* is_narrow */ true,
280       /* weak */ false,
281       /* acquire */ true);
282   %}
283   ins_pipe(pipe_slow);
284 %}
285 
286 instruct compareAndExchange_P_shenandoah(iRegPNoSp res, indirect mem, iRegP oldval, iRegP newval, rFlagsReg cr)
287 %{
288   match(Set res (CompareAndExchangeP mem (Binary oldval newval)));
289   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
290   ins_cost(2*VOLATILE_REF_COST);
291   effect(TEMP_DEF res, KILL cr);
292   format %{
293     "cae_P_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
294   %}
295   ins_encode %{
296     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
297 
298     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
299       $res$$Register,
300       $mem$$base$$Register,
301       $oldval$$Register,
302       $newval$$Register,
303       /* exchange */ true,
304       /* is_narrow */ false,
305       /* weak */ false,
306       /* acquire */ false);
307   %}
308   ins_pipe(pipe_slow);
309 %}
310 
311 instruct compareAndExchange_P_A_shenandoah(iRegPNoSp res, indirect mem, iRegP oldval, iRegP newval, rFlagsReg cr)
312 %{
313   match(Set res (CompareAndExchangeP mem (Binary oldval newval)));
314   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
315   ins_cost(2*VOLATILE_REF_COST);
316   effect(TEMP_DEF res, KILL cr);
317   format %{
318     "cae_P_shenandoah $mem, $oldval, $newval\t# (ptr) if $mem == $oldval then $mem <-- $newval"
319   %}
320   ins_encode %{
321     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
322 
323     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
324       $res$$Register,
325       $mem$$base$$Register,
326       $oldval$$Register,
327       $newval$$Register,
328       /* exchange */ true,
329       /* is_narrow */ false,
330       /* weak */ false,
331       /* acquire */ true);
332   %}
333   ins_pipe(pipe_slow);
334 %}
335 
336 instruct weakCompareAndSwap_N_shenandoah(iRegINoSp res, indirect mem, iRegNNoSp oldval, iRegN newval, rFlagsReg cr)
337 %{
338   match(Set res (WeakCompareAndSwapN mem (Binary oldval newval)));
339   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
340   ins_cost(VOLATILE_REF_COST);
341   effect(TEMP_DEF res, KILL cr);
342   format %{
343     "cae_N_weak_shenandoah $res = $mem, $oldval, $newval\t# (N, weak) if $mem == $oldval then $mem <-- $newval\n\t"
344     "csetw $res, EQ\t# $res <-- (EQ ? 1 : 0)"
345   %}
346   ins_encode %{
347     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
348 
349     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
350       $res$$Register,
351       $mem$$base$$Register,
352       $oldval$$Register,
353       $newval$$Register,
354       /* exchange */ false,
355       /* is_narrow */ true,
356       /* weak */ true,
357       /* acquire */ false);
358   %}
359   ins_pipe(pipe_slow);
360 %}
361 
362 instruct weakCompareAndSwap_N_A_shenandoah(iRegINoSp res, indirect mem, iRegNNoSp oldval, iRegN newval, rFlagsReg cr)
363 %{
364   match(Set res (WeakCompareAndSwapN mem (Binary oldval newval)));
365   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
366   ins_cost(VOLATILE_REF_COST);
367   effect(TEMP_DEF res, KILL cr);
368   format %{
369     "cae_N_weak_shenandoah $res = $mem, $oldval, $newval\t# (N, weak) if $mem == $oldval then $mem <-- $newval\n\t"
370     "csetw $res, EQ\t# $res <-- (EQ ? 1 : 0)"
371   %}
372   ins_encode %{
373     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
374 
375     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
376       $res$$Register,
377       $mem$$base$$Register,
378       $oldval$$Register,
379       $newval$$Register,
380       /* exchange */ false,
381       /* is_narrow */ true,
382       /* weak */ true,
383       /* acquire */ true);
384   %}
385   ins_pipe(pipe_slow);
386 %}
387 
388 instruct weakCompareAndSwap_P_shenandoah(iRegINoSp res, indirect mem, iRegPNoSp oldval, iRegP newval, rFlagsReg cr)
389 %{
390   match(Set res (WeakCompareAndSwapP mem (Binary oldval newval)));
391   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
392   ins_cost(VOLATILE_REF_COST);
393   effect(TEMP_DEF res, KILL cr);
394   format %{
395     "cae_P_weak_shenandoah $res = $mem, $oldval, $newval\t# (P, weak) if $mem == $oldval then $mem <-- $newval\n\t"
396     "csetw $res, EQ\t# $res <-- (EQ ? 1 : 0)"
397   %}
398   ins_encode %{
399     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
400 
401     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
402       $res$$Register,
403       $mem$$base$$Register,
404       $oldval$$Register,
405       $newval$$Register,
406       /* exchange */ false,
407       /* is_narrow */ false,
408       /* weak */ true,
409       /* acquire */ false);
410   %}
411   ins_pipe(pipe_slow);
412 %}
413 
414 instruct weakCompareAndSwap_P_A_shenandoah(iRegINoSp res, indirect mem, iRegPNoSp oldval, iRegP newval, rFlagsReg cr)
415 %{
416   match(Set res (WeakCompareAndSwapP mem (Binary oldval newval)));
417   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
418   ins_cost(VOLATILE_REF_COST);
419   effect(TEMP_DEF res, KILL cr);
420   format %{
421     "cae_P_weak_shenandoah $res = $mem, $oldval, $newval\t# (P, weak) if $mem == $oldval then $mem <-- $newval\n\t"
422     "csetw $res, EQ\t# $res <-- (EQ ? 1 : 0)"
423   %}
424   ins_encode %{
425     guarantee($mem$$index == -1 && $mem$$disp == 0, "impossible encoding");
426 
427     ShenandoahBarrierSet::assembler()->compare_and_set_c2(this, masm,
428       $res$$Register,
429       $mem$$base$$Register,
430       $oldval$$Register,
431       $newval$$Register,
432       /* exchange */ false,
433       /* is_narrow */ false,
434       /* weak */ true,
435       /* acquire */ true);
436   %}
437   ins_pipe(pipe_slow);
438 %}
439 
440 instruct getAndSet_P_shenandoah(indirect mem, iRegP newval, iRegPNoSp preval,  rFlagsReg cr)
441 %{
442   match(Set preval (GetAndSetP mem newval));
443   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
444   effect(TEMP_DEF preval, KILL cr);
445   ins_cost(2*VOLATILE_REF_COST);
446   format %{ "get_and_set_P $preval, $newval, [$mem]" %}
447   ins_encode %{
448     ShenandoahBarrierSet::assembler()->get_and_set_c2(this, masm,
449       $preval$$Register,
450       $newval$$Register,
451       $mem$$Register,
452       /* acquire */ false);
453   %}
454   ins_pipe(pipe_serial);
455 %}
456 
457 instruct getAndSet_P_A_shenandoah(indirect mem, iRegP newval, iRegPNoSp preval,  rFlagsReg cr)
458 %{
459   match(Set preval (GetAndSetP mem newval));
460   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
461   effect(TEMP_DEF preval, KILL cr);
462   ins_cost(2*VOLATILE_REF_COST);
463   format %{ "get_and_set_P $preval, $newval, [$mem]" %}
464   ins_encode %{
465     ShenandoahBarrierSet::assembler()->get_and_set_c2(this, masm,
466       $preval$$Register,
467       $newval$$Register,
468       $mem$$Register,
469       /* acquire */ true);
470   %}
471   ins_pipe(pipe_serial);
472 %}
473 
474 instruct getAndSet_N_shenandoah(indirect mem, iRegN newval, iRegNNoSp preval, rFlagsReg cr)
475 %{
476   match(Set preval (GetAndSetN mem newval));
477   predicate(UseShenandoahGC && !needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
478   effect(TEMP_DEF preval, KILL cr);
479   ins_cost(2*VOLATILE_REF_COST);
480   format %{ "get_and_set_N $preval, $newval, [$mem]" %}
481   ins_encode %{
482     ShenandoahBarrierSet::assembler()->get_and_set_c2(this, masm,
483       $preval$$Register,
484       $newval$$Register,
485       $mem$$Register,
486       /* acquire */ false);
487   %}
488   ins_pipe(pipe_serial);
489 %}
490 
491 instruct getAndSet_N_A_shenandoah(indirect mem, iRegN newval, iRegNNoSp preval, rFlagsReg cr)
492 %{
493   match(Set preval (GetAndSetN mem newval));
494   predicate(UseShenandoahGC && needs_acquiring_load_exclusive(n) && n->as_LoadStore()->barrier_data() != 0);
495   effect(TEMP_DEF preval, KILL cr);
496   ins_cost(2*VOLATILE_REF_COST);
497   format %{ "get_and_set_N $preval, $newval, [$mem]" %}
498   ins_encode %{
499     ShenandoahBarrierSet::assembler()->get_and_set_c2(this, masm,
500       $preval$$Register,
501       $newval$$Register,
502       $mem$$Register,
503       /* acquire */ true);
504   %}
505   ins_pipe(pipe_serial);
506 %}
507 
508 instruct load_P_Normal_shenandoah(iRegPNoSp dst, memory8 mem, rFlagsReg cr)
509 %{
510   match(Set dst (LoadP mem));
511   predicate(UseShenandoahGC && !needs_acquiring_load(n) && n->as_Load()->barrier_data() != 0);
512   effect(TEMP_DEF dst, KILL cr);
513   // The main load is a candidate to implement implicit null checks.
514   ins_is_late_expanded_null_check_candidate(true);
515   format %{ "ldr  $dst, $mem\t# ptr" %}
516   ins_encode %{
517     Address addr = mem2address($mem->opcode(), as_Register($mem$$base), $mem$$index, $mem$$scale, $mem$$disp);
518     if (addr.getMode() == Address::base_plus_offset) {
519       addr = __ legitimize_address(addr, /* size_in_memory */ 8, rscratch1);
520     }
521     ShenandoahBarrierSet::assembler()->load_c2(this, masm, $dst$$Register, addr, /* is_narrow */ false, /* is_acquire */ false);
522   %}
523   ins_cost(3*INSN_COST);
524   ins_pipe(pipe_class_memory);
525 %}
526 
527 instruct load_P_Volatile_shenandoah(iRegPNoSp dst, indirect mem, rFlagsReg cr)
528 %{
529   match(Set dst (LoadP mem));
530   predicate(UseShenandoahGC && needs_acquiring_load(n) && n->as_Load()->barrier_data() != 0);
531   effect(TEMP_DEF dst, KILL cr);
532   // The main load is a candidate to implement implicit null checks.
533   ins_is_late_expanded_null_check_candidate(true);
534   format %{ "ldr  $dst, $mem\t# ptr" %}
535   ins_encode %{
536     ShenandoahBarrierSet::assembler()->load_c2(this, masm, $dst$$Register, Address($mem$$Register), /* is_narrow */ false, /* is_acquire */ true);
537   %}
538   ins_cost(3*INSN_COST);
539   ins_pipe(pipe_class_memory);
540 %}
541 
542 instruct load_N_Normal_shenandoah(iRegNNoSp dst, memory4 mem, rFlagsReg cr)
543 %{
544   match(Set dst (LoadN mem));
545   predicate(UseShenandoahGC && !needs_acquiring_load(n) && n->as_Load()->barrier_data() != 0);
546   effect(TEMP_DEF dst, KILL cr);
547   // The main load is a candidate to implement implicit null checks.
548   ins_is_late_expanded_null_check_candidate(true);
549   format %{ "ldrw  $dst, $mem\t# ptr" %}
550   ins_encode %{
551     Address addr = mem2address($mem->opcode(), as_Register($mem$$base), $mem$$index, $mem$$scale, $mem$$disp);
552     if (addr.getMode() == Address::base_plus_offset) {
553       addr = __ legitimize_address(addr, /* size_in_memory */ 4, rscratch1);
554     }
555     ShenandoahBarrierSet::assembler()->load_c2(this, masm, $dst$$Register, addr, /* is_narrow */ true, /* is_acquire */ false);
556   %}
557   ins_cost(3*INSN_COST);
558   ins_pipe(pipe_class_memory);
559 %}
560 
561 instruct load_N_Volatile_shenandoah(iRegNNoSp dst, indirect mem, rFlagsReg cr)
562 %{
563   match(Set dst (LoadN mem));
564   predicate(UseShenandoahGC && needs_acquiring_load(n) && n->as_Load()->barrier_data() != 0);
565   effect(TEMP_DEF dst, KILL cr);
566   // The main load is a candidate to implement implicit null checks.
567   ins_is_late_expanded_null_check_candidate(true);
568   format %{ "ldrw  $dst, $mem\t# ptr" %}
569   ins_encode %{
570     ShenandoahBarrierSet::assembler()->load_c2(this, masm, $dst$$Register, Address($mem$$Register), /* is_narrow */ true, /* is_acquire */ true);
571   %}
572   ins_cost(VOLATILE_REF_COST);
573   ins_pipe(pipe_class_memory);
574 %}
575