2 ** FOLD: Constant Folding, Algebraic Simplifications and Reassociation.
3 ** ABCelim: Array Bounds Check Elimination.
4 ** CSE: Common-Subexpression Elimination.
5 ** Copyright (C) 2005-2013 Mike Pall. See Copyright Notice in luajit.h
26 #include "lj_carith.h"
28 #include "lj_strscan.h"
30 /* Here's a short description how the FOLD engine processes instructions:
32 ** The FOLD engine receives a single instruction stored in fins (J->fold.ins).
33 ** The instruction and its operands are used to select matching fold rules.
34 ** These are applied iteratively until a fixed point is reached.
36 ** The 8 bit opcode of the instruction itself plus the opcodes of the
37 ** two instructions referenced by its operands form a 24 bit key
38 ** 'ins left right' (unused operands -> 0, literals -> lowest 8 bits).
40 ** This key is used for partial matching against the fold rules. The
41 ** left/right operand fields of the key are successively masked with
42 ** the 'any' wildcard, from most specific to least specific:
49 ** The masked key is used to lookup a matching fold rule in a semi-perfect
50 ** hash table. If a matching rule is found, the related fold function is run.
51 ** Multiple rules can share the same fold function. A fold rule may return
52 ** one of several special values:
54 ** - NEXTFOLD means no folding was applied, because an additional test
55 ** inside the fold function failed. Matching continues against less
56 ** specific fold rules. Finally the instruction is passed on to CSE.
58 ** - RETRYFOLD means the instruction was modified in-place. Folding is
59 ** retried as if this instruction had just been received.
61 ** All other return values are terminal actions -- no further folding is
64 ** - INTFOLD(i) returns a reference to the integer constant i.
66 ** - LEFTFOLD and RIGHTFOLD return the left/right operand reference
67 ** without emitting an instruction.
69 ** - CSEFOLD and EMITFOLD pass the instruction directly to CSE or emit
70 ** it without passing through any further optimizations.
72 ** - FAILFOLD, DROPFOLD and CONDFOLD only apply to instructions which have
73 ** no result (e.g. guarded assertions): FAILFOLD means the guard would
74 ** always fail, i.e. the current trace is pointless. DROPFOLD means
75 ** the guard is always true and has been eliminated. CONDFOLD is a
76 ** shortcut for FAILFOLD + cond (i.e. drop if true, otherwise fail).
78 ** - Any other return value is interpreted as an IRRef or TRef. This
79 ** can be a reference to an existing or a newly created instruction.
80 ** Only the least-significant 16 bits (IRRef1) are used to form a TRef
81 ** which is finally returned to the caller.
83 ** The FOLD engine receives instructions both from the trace recorder and
84 ** substituted instructions from LOOP unrolling. This means all types
85 ** of instructions may end up here, even though the recorder bypasses
86 ** FOLD in some cases. Thus all loads, stores and allocations must have
87 ** an any/any rule to avoid being passed on to CSE.
89 ** Carefully read the following requirements before adding or modifying
92 ** Requirement #1: All fold rules must preserve their destination type.
94 ** Consistently use INTFOLD() (KINT result) or lj_ir_knum() (KNUM result).
95 ** Never use lj_ir_knumint() which can have either a KINT or KNUM result.
97 ** Requirement #2: Fold rules should not create *new* instructions which
98 ** reference operands *across* PHIs.
100 ** E.g. a RETRYFOLD with 'fins->op1 = fleft->op1' is invalid if the
101 ** left operand is a PHI. Then fleft->op1 would point across the PHI
102 ** frontier to an invariant instruction. Adding a PHI for this instruction
103 ** would be counterproductive. The solution is to add a barrier which
104 ** prevents folding across PHIs, i.e. 'PHIBARRIER(fleft)' in this case.
105 ** The only exception is for recurrences with high latencies like
106 ** repeated int->num->int conversions.
108 ** One could relax this condition a bit if the referenced instruction is
109 ** a PHI, too. But this often leads to worse code due to excessive
110 ** register shuffling.
112 ** Note: returning *existing* instructions (e.g. LEFTFOLD) is ok, though.
113 ** Even returning fleft->op1 would be ok, because a new PHI will added,
114 ** if needed. But again, this leads to excessive register shuffling and
115 ** should be avoided.
117 ** Requirement #3: The set of all fold rules must be monotonic to guarantee
120 ** The goal is optimization, so one primarily wants to add strength-reducing
121 ** rules. This means eliminating an instruction or replacing an instruction
122 ** with one or more simpler instructions. Don't add fold rules which point
123 ** into the other direction.
125 ** Some rules (like commutativity) do not directly reduce the strength of
126 ** an instruction, but enable other fold rules (e.g. by moving constants
127 ** to the right operand). These rules must be made unidirectional to avoid
130 ** Rule of thumb: the trace recorder expands the IR and FOLD shrinks it.
133 /* Some local macros to save typing. Undef'd at the end. */
134 #define IR(ref) (&J->cur.ir[(ref)])
135 #define fins (&J->fold.ins)
136 #define fleft (&J->fold.left)
137 #define fright (&J->fold.right)
138 #define knumleft (ir_knum(fleft)->n)
139 #define knumright (ir_knum(fright)->n)
141 /* Pass IR on to next optimization in chain (FOLD). */
142 #define emitir(ot, a, b) (lj_ir_set(J, (ot), (a), (b)), lj_opt_fold(J))
144 /* Fold function type. Fastcall on x86 significantly reduces their size. */
145 typedef IRRef (LJ_FASTCALL
*FoldFunc
)(jit_State
*J
);
147 /* Macros for the fold specs, so buildvm can recognize them. */
150 #define LJFOLDF(name) static TRef LJ_FASTCALL fold_##name(jit_State *J)
151 /* Note: They must be at the start of a line or buildvm ignores them! */
153 /* Barrier to prevent using operands across PHIs. */
154 #define PHIBARRIER(ir) if (irt_isphi((ir)->t)) return NEXTFOLD
156 /* Barrier to prevent folding across a GC step.
157 ** GC steps can only happen at the head of a trace and at LOOP.
158 ** And the GC is only driven forward if there is at least one allocation.
160 #define gcstep_barrier(J, ref) \
161 ((ref) < J->chain[IR_LOOP] && \
162 (J->chain[IR_SNEW] || J->chain[IR_XSNEW] || \
163 J->chain[IR_TNEW] || J->chain[IR_TDUP] || \
164 J->chain[IR_CNEW] || J->chain[IR_CNEWI] || J->chain[IR_TOSTR]))
166 /* -- Constant folding for FP numbers ------------------------------------- */
168 LJFOLD(ADD KNUM KNUM
)
169 LJFOLD(SUB KNUM KNUM
)
170 LJFOLD(MUL KNUM KNUM
)
171 LJFOLD(DIV KNUM KNUM
)
172 LJFOLD(NEG KNUM KNUM
)
173 LJFOLD(ABS KNUM KNUM
)
174 LJFOLD(ATAN2 KNUM KNUM
)
175 LJFOLD(LDEXP KNUM KNUM
)
176 LJFOLD(MIN KNUM KNUM
)
177 LJFOLD(MAX KNUM KNUM
)
178 LJFOLDF(kfold_numarith
)
180 lua_Number a
= knumleft
;
181 lua_Number b
= knumright
;
182 lua_Number y
= lj_vm_foldarith(a
, b
, fins
->o
- IR_ADD
);
183 return lj_ir_knum(J
, y
);
186 LJFOLD(LDEXP KNUM KINT
)
189 #if LJ_TARGET_X86ORX64
193 return lj_ir_knum(J
, ldexp(knumleft
, fright
->i
));
197 LJFOLD(FPMATH KNUM any
)
198 LJFOLDF(kfold_fpmath
)
200 lua_Number a
= knumleft
;
201 lua_Number y
= lj_vm_foldfpm(a
, fins
->op2
);
202 return lj_ir_knum(J
, y
);
205 LJFOLD(POW KNUM KINT
)
206 LJFOLDF(kfold_numpow
)
208 lua_Number a
= knumleft
;
209 lua_Number b
= (lua_Number
)fright
->i
;
210 lua_Number y
= lj_vm_foldarith(a
, b
, IR_POW
- IR_ADD
);
211 return lj_ir_knum(J
, y
);
214 /* Must not use kfold_kref for numbers (could be NaN). */
221 LJFOLD(ULT KNUM KNUM
)
222 LJFOLD(UGE KNUM KNUM
)
223 LJFOLD(ULE KNUM KNUM
)
224 LJFOLD(UGT KNUM KNUM
)
225 LJFOLDF(kfold_numcomp
)
227 return CONDFOLD(lj_ir_numcmp(knumleft
, knumright
, (IROp
)fins
->o
));
230 /* -- Constant folding for 32 bit integers -------------------------------- */
232 static int32_t kfold_intop(int32_t k1
, int32_t k2
, IROp op
)
235 case IR_ADD
: k1
+= k2
; break;
236 case IR_SUB
: k1
-= k2
; break;
237 case IR_MUL
: k1
*= k2
; break;
238 case IR_MOD
: k1
= lj_vm_modi(k1
, k2
); break;
239 case IR_NEG
: k1
= -k1
; break;
240 case IR_BAND
: k1
&= k2
; break;
241 case IR_BOR
: k1
|= k2
; break;
242 case IR_BXOR
: k1
^= k2
; break;
243 case IR_BSHL
: k1
<<= (k2
& 31); break;
244 case IR_BSHR
: k1
= (int32_t)((uint32_t)k1
>> (k2
& 31)); break;
245 case IR_BSAR
: k1
>>= (k2
& 31); break;
246 case IR_BROL
: k1
= (int32_t)lj_rol((uint32_t)k1
, (k2
& 31)); break;
247 case IR_BROR
: k1
= (int32_t)lj_ror((uint32_t)k1
, (k2
& 31)); break;
248 case IR_MIN
: k1
= k1
< k2
? k1
: k2
; break;
249 case IR_MAX
: k1
= k1
> k2
? k1
: k2
; break;
250 default: lua_assert(0); break;
255 LJFOLD(ADD KINT KINT
)
256 LJFOLD(SUB KINT KINT
)
257 LJFOLD(MUL KINT KINT
)
258 LJFOLD(MOD KINT KINT
)
259 LJFOLD(NEG KINT KINT
)
260 LJFOLD(BAND KINT KINT
)
261 LJFOLD(BOR KINT KINT
)
262 LJFOLD(BXOR KINT KINT
)
263 LJFOLD(BSHL KINT KINT
)
264 LJFOLD(BSHR KINT KINT
)
265 LJFOLD(BSAR KINT KINT
)
266 LJFOLD(BROL KINT KINT
)
267 LJFOLD(BROR KINT KINT
)
268 LJFOLD(MIN KINT KINT
)
269 LJFOLD(MAX KINT KINT
)
270 LJFOLDF(kfold_intarith
)
272 return INTFOLD(kfold_intop(fleft
->i
, fright
->i
, (IROp
)fins
->o
));
275 LJFOLD(ADDOV KINT KINT
)
276 LJFOLD(SUBOV KINT KINT
)
277 LJFOLD(MULOV KINT KINT
)
278 LJFOLDF(kfold_intovarith
)
280 lua_Number n
= lj_vm_foldarith((lua_Number
)fleft
->i
, (lua_Number
)fright
->i
,
282 int32_t k
= lj_num2int(n
);
283 if (n
!= (lua_Number
)k
)
291 return INTFOLD(~fleft
->i
);
297 return INTFOLD((int32_t)lj_bswap((uint32_t)fleft
->i
));
304 LJFOLD(ULT KINT KINT
)
305 LJFOLD(UGE KINT KINT
)
306 LJFOLD(ULE KINT KINT
)
307 LJFOLD(UGT KINT KINT
)
308 LJFOLD(ABC KINT KINT
)
309 LJFOLDF(kfold_intcomp
)
311 int32_t a
= fleft
->i
, b
= fright
->i
;
312 switch ((IROp
)fins
->o
) {
313 case IR_LT
: return CONDFOLD(a
< b
);
314 case IR_GE
: return CONDFOLD(a
>= b
);
315 case IR_LE
: return CONDFOLD(a
<= b
);
316 case IR_GT
: return CONDFOLD(a
> b
);
317 case IR_ULT
: return CONDFOLD((uint32_t)a
< (uint32_t)b
);
318 case IR_UGE
: return CONDFOLD((uint32_t)a
>= (uint32_t)b
);
319 case IR_ULE
: return CONDFOLD((uint32_t)a
<= (uint32_t)b
);
321 case IR_UGT
: return CONDFOLD((uint32_t)a
> (uint32_t)b
);
322 default: lua_assert(0); return FAILFOLD
;
327 LJFOLDF(kfold_intcomp0
)
334 /* -- Constant folding for 64 bit integers -------------------------------- */
336 static uint64_t kfold_int64arith(uint64_t k1
, uint64_t k2
, IROp op
)
339 #if LJ_64 || LJ_HASFFI
340 case IR_ADD
: k1
+= k2
; break;
341 case IR_SUB
: k1
-= k2
; break;
344 case IR_MUL
: k1
*= k2
; break;
345 case IR_BAND
: k1
&= k2
; break;
346 case IR_BOR
: k1
|= k2
; break;
347 case IR_BXOR
: k1
^= k2
; break;
349 default: UNUSED(k2
); lua_assert(0); break;
354 LJFOLD(ADD KINT64 KINT64
)
355 LJFOLD(SUB KINT64 KINT64
)
356 LJFOLD(MUL KINT64 KINT64
)
357 LJFOLD(BAND KINT64 KINT64
)
358 LJFOLD(BOR KINT64 KINT64
)
359 LJFOLD(BXOR KINT64 KINT64
)
360 LJFOLDF(kfold_int64arith
)
362 return INT64FOLD(kfold_int64arith(ir_k64(fleft
)->u64
,
363 ir_k64(fright
)->u64
, (IROp
)fins
->o
));
366 LJFOLD(DIV KINT64 KINT64
)
367 LJFOLD(MOD KINT64 KINT64
)
368 LJFOLD(POW KINT64 KINT64
)
369 LJFOLDF(kfold_int64arith2
)
372 uint64_t k1
= ir_k64(fleft
)->u64
, k2
= ir_k64(fright
)->u64
;
373 if (irt_isi64(fins
->t
)) {
374 k1
= fins
->o
== IR_DIV
? lj_carith_divi64((int64_t)k1
, (int64_t)k2
) :
375 fins
->o
== IR_MOD
? lj_carith_modi64((int64_t)k1
, (int64_t)k2
) :
376 lj_carith_powi64((int64_t)k1
, (int64_t)k2
);
378 k1
= fins
->o
== IR_DIV
? lj_carith_divu64(k1
, k2
) :
379 fins
->o
== IR_MOD
? lj_carith_modu64(k1
, k2
) :
380 lj_carith_powu64(k1
, k2
);
382 return INT64FOLD(k1
);
384 UNUSED(J
); lua_assert(0); return FAILFOLD
;
388 LJFOLD(BSHL KINT64 KINT
)
389 LJFOLD(BSHR KINT64 KINT
)
390 LJFOLD(BSAR KINT64 KINT
)
391 LJFOLD(BROL KINT64 KINT
)
392 LJFOLD(BROR KINT64 KINT
)
393 LJFOLDF(kfold_int64shift
)
395 #if LJ_HASFFI || LJ_64
396 uint64_t k
= ir_k64(fleft
)->u64
;
397 int32_t sh
= (fright
->i
& 63);
398 switch ((IROp
)fins
->o
) {
399 case IR_BSHL
: k
<<= sh
; break;
401 case IR_BSHR
: k
>>= sh
; break;
402 case IR_BSAR
: k
= (uint64_t)((int64_t)k
>> sh
); break;
403 case IR_BROL
: k
= lj_rol(k
, sh
); break;
404 case IR_BROR
: k
= lj_ror(k
, sh
); break;
406 default: lua_assert(0); break;
410 UNUSED(J
); lua_assert(0); return FAILFOLD
;
415 LJFOLDF(kfold_bnot64
)
418 return INT64FOLD(~ir_k64(fleft
)->u64
);
420 UNUSED(J
); lua_assert(0); return FAILFOLD
;
425 LJFOLDF(kfold_bswap64
)
428 return INT64FOLD(lj_bswap64(ir_k64(fleft
)->u64
));
430 UNUSED(J
); lua_assert(0); return FAILFOLD
;
434 LJFOLD(LT KINT64 KINT64
)
435 LJFOLD(GE KINT64 KINT64
)
436 LJFOLD(LE KINT64 KINT64
)
437 LJFOLD(GT KINT64 KINT64
)
438 LJFOLD(ULT KINT64 KINT64
)
439 LJFOLD(UGE KINT64 KINT64
)
440 LJFOLD(ULE KINT64 KINT64
)
441 LJFOLD(UGT KINT64 KINT64
)
442 LJFOLDF(kfold_int64comp
)
445 uint64_t a
= ir_k64(fleft
)->u64
, b
= ir_k64(fright
)->u64
;
446 switch ((IROp
)fins
->o
) {
447 case IR_LT
: return CONDFOLD(a
< b
);
448 case IR_GE
: return CONDFOLD(a
>= b
);
449 case IR_LE
: return CONDFOLD(a
<= b
);
450 case IR_GT
: return CONDFOLD(a
> b
);
451 case IR_ULT
: return CONDFOLD((uint64_t)a
< (uint64_t)b
);
452 case IR_UGE
: return CONDFOLD((uint64_t)a
>= (uint64_t)b
);
453 case IR_ULE
: return CONDFOLD((uint64_t)a
<= (uint64_t)b
);
454 case IR_UGT
: return CONDFOLD((uint64_t)a
> (uint64_t)b
);
455 default: lua_assert(0); return FAILFOLD
;
458 UNUSED(J
); lua_assert(0); return FAILFOLD
;
462 LJFOLD(UGE any KINT64
)
463 LJFOLDF(kfold_int64comp0
)
466 if (ir_k64(fright
)->u64
== 0)
470 UNUSED(J
); lua_assert(0); return FAILFOLD
;
474 /* -- Constant folding for strings ---------------------------------------- */
476 LJFOLD(SNEW KKPTR KINT
)
477 LJFOLDF(kfold_snew_kptr
)
479 GCstr
*s
= lj_str_new(J
->L
, (const char *)ir_kptr(fleft
), (size_t)fright
->i
);
480 return lj_ir_kstr(J
, s
);
483 LJFOLD(SNEW any KINT
)
484 LJFOLDF(kfold_snew_empty
)
487 return lj_ir_kstr(J
, &J2G(J
)->strempty
);
491 LJFOLD(STRREF KGC KINT
)
492 LJFOLDF(kfold_strref
)
494 GCstr
*str
= ir_kstr(fleft
);
495 lua_assert((MSize
)fright
->i
<= str
->len
);
496 return lj_ir_kkptr(J
, (char *)strdata(str
) + fright
->i
);
499 LJFOLD(STRREF SNEW any
)
500 LJFOLDF(kfold_strref_snew
)
503 if (irref_isk(fins
->op2
) && fright
->i
== 0) {
504 return fleft
->op1
; /* strref(snew(ptr, len), 0) ==> ptr */
506 /* Reassociate: strref(snew(strref(str, a), len), b) ==> strref(str, a+b) */
507 IRIns
*ir
= IR(fleft
->op1
);
508 IRRef1 str
= ir
->op1
; /* IRIns * is not valid across emitir. */
509 lua_assert(ir
->o
== IR_STRREF
);
511 fins
->op2
= emitir(IRTI(IR_ADD
), ir
->op2
, fins
->op2
); /* Clobbers fins! */
513 fins
->ot
= IRT(IR_STRREF
, IRT_P32
);
519 LJFOLD(CALLN CARG IRCALL_lj_str_cmp
)
520 LJFOLDF(kfold_strcmp
)
522 if (irref_isk(fleft
->op1
) && irref_isk(fleft
->op2
)) {
523 GCstr
*a
= ir_kstr(IR(fleft
->op1
));
524 GCstr
*b
= ir_kstr(IR(fleft
->op2
));
525 return INTFOLD(lj_str_cmp(a
, b
));
530 /* -- Constant folding of pointer arithmetic ------------------------------ */
533 LJFOLD(ADD KGC KINT64
)
534 LJFOLDF(kfold_add_kgc
)
536 GCobj
*o
= ir_kgc(fleft
);
538 ptrdiff_t ofs
= (ptrdiff_t)ir_kint64(fright
)->u64
;
540 ptrdiff_t ofs
= fright
->i
;
543 if (irt_iscdata(fleft
->t
)) {
544 CType
*ct
= ctype_raw(ctype_ctsG(J2G(J
)), gco2cd(o
)->ctypeid
);
545 if (ctype_isnum(ct
->info
) || ctype_isenum(ct
->info
) ||
546 ctype_isptr(ct
->info
) || ctype_isfunc(ct
->info
) ||
547 ctype_iscomplex(ct
->info
) || ctype_isvector(ct
->info
))
548 return lj_ir_kkptr(J
, (char *)o
+ ofs
);
551 return lj_ir_kptr(J
, (char *)o
+ ofs
);
554 LJFOLD(ADD KPTR KINT
)
555 LJFOLD(ADD KPTR KINT64
)
556 LJFOLD(ADD KKPTR KINT
)
557 LJFOLD(ADD KKPTR KINT64
)
558 LJFOLDF(kfold_add_kptr
)
560 void *p
= ir_kptr(fleft
);
562 ptrdiff_t ofs
= (ptrdiff_t)ir_kint64(fright
)->u64
;
564 ptrdiff_t ofs
= fright
->i
;
566 return lj_ir_kptr_(J
, fleft
->o
, (char *)p
+ ofs
);
571 LJFOLD(ADD any KKPTR
)
572 LJFOLDF(kfold_add_kright
)
574 if (fleft
->o
== IR_KINT
|| fleft
->o
== IR_KINT64
) {
575 IRRef1 tmp
= fins
->op1
; fins
->op1
= fins
->op2
; fins
->op2
= tmp
;
581 /* -- Constant folding of conversions ------------------------------------- */
583 LJFOLD(TOBIT KNUM KNUM
)
586 return INTFOLD(lj_num2bit(knumleft
));
589 LJFOLD(CONV KINT IRCONV_NUM_INT
)
590 LJFOLDF(kfold_conv_kint_num
)
592 return lj_ir_knum(J
, (lua_Number
)fleft
->i
);
595 LJFOLD(CONV KINT IRCONV_NUM_U32
)
596 LJFOLDF(kfold_conv_kintu32_num
)
598 return lj_ir_knum(J
, (lua_Number
)(uint32_t)fleft
->i
);
601 LJFOLD(CONV KINT IRCONV_INT_I8
)
602 LJFOLD(CONV KINT IRCONV_INT_U8
)
603 LJFOLD(CONV KINT IRCONV_INT_I16
)
604 LJFOLD(CONV KINT IRCONV_INT_U16
)
605 LJFOLDF(kfold_conv_kint_ext
)
607 int32_t k
= fleft
->i
;
608 if ((fins
->op2
& IRCONV_SRCMASK
) == IRT_I8
) k
= (int8_t)k
;
609 else if ((fins
->op2
& IRCONV_SRCMASK
) == IRT_U8
) k
= (uint8_t)k
;
610 else if ((fins
->op2
& IRCONV_SRCMASK
) == IRT_I16
) k
= (int16_t)k
;
611 else k
= (uint16_t)k
;
615 LJFOLD(CONV KINT IRCONV_I64_INT
)
616 LJFOLD(CONV KINT IRCONV_U64_INT
)
617 LJFOLD(CONV KINT IRCONV_I64_U32
)
618 LJFOLD(CONV KINT IRCONV_U64_U32
)
619 LJFOLDF(kfold_conv_kint_i64
)
621 if ((fins
->op2
& IRCONV_SEXT
))
622 return INT64FOLD((uint64_t)(int64_t)fleft
->i
);
624 return INT64FOLD((uint64_t)(int64_t)(uint32_t)fleft
->i
);
627 LJFOLD(CONV KINT64 IRCONV_NUM_I64
)
628 LJFOLDF(kfold_conv_kint64_num_i64
)
630 return lj_ir_knum(J
, (lua_Number
)(int64_t)ir_kint64(fleft
)->u64
);
633 LJFOLD(CONV KINT64 IRCONV_NUM_U64
)
634 LJFOLDF(kfold_conv_kint64_num_u64
)
636 return lj_ir_knum(J
, (lua_Number
)ir_kint64(fleft
)->u64
);
639 LJFOLD(CONV KINT64 IRCONV_INT_I64
)
640 LJFOLD(CONV KINT64 IRCONV_U32_I64
)
641 LJFOLDF(kfold_conv_kint64_int_i64
)
643 return INTFOLD((int32_t)ir_kint64(fleft
)->u64
);
646 LJFOLD(CONV KNUM IRCONV_INT_NUM
)
647 LJFOLDF(kfold_conv_knum_int_num
)
649 lua_Number n
= knumleft
;
650 if (!(fins
->op2
& IRCONV_TRUNC
)) {
651 int32_t k
= lj_num2int(n
);
652 if (irt_isguard(fins
->t
) && n
!= (lua_Number
)k
) {
653 /* We're about to create a guard which always fails, like CONV +1.5.
654 ** Some pathological loops cause this during LICM, e.g.:
655 ** local x,k,t = 0,1.5,{1,[1.5]=2}
656 ** for i=1,200 do x = x+ t[k]; k = k == 1 and 1.5 or 1 end
663 return INTFOLD((int32_t)n
);
667 LJFOLD(CONV KNUM IRCONV_U32_NUM
)
668 LJFOLDF(kfold_conv_knum_u32_num
)
670 lua_assert((fins
->op2
& IRCONV_TRUNC
));
672 { /* Workaround for MSVC bug. */
673 volatile uint32_t u
= (uint32_t)knumleft
;
674 return INTFOLD((int32_t)u
);
677 return INTFOLD((int32_t)(uint32_t)knumleft
);
681 LJFOLD(CONV KNUM IRCONV_I64_NUM
)
682 LJFOLDF(kfold_conv_knum_i64_num
)
684 lua_assert((fins
->op2
& IRCONV_TRUNC
));
685 return INT64FOLD((uint64_t)(int64_t)knumleft
);
688 LJFOLD(CONV KNUM IRCONV_U64_NUM
)
689 LJFOLDF(kfold_conv_knum_u64_num
)
691 lua_assert((fins
->op2
& IRCONV_TRUNC
));
692 return INT64FOLD(lj_num2u64(knumleft
));
696 LJFOLDF(kfold_tostr_knum
)
698 return lj_ir_kstr(J
, lj_str_fromnum(J
->L
, &knumleft
));
702 LJFOLDF(kfold_tostr_kint
)
704 return lj_ir_kstr(J
, lj_str_fromint(J
->L
, fleft
->i
));
711 if (lj_strscan_num(ir_kstr(fleft
), &n
))
712 return lj_ir_knum(J
, numV(&n
));
716 /* -- Constant folding of equality checks --------------------------------- */
718 /* Don't constant-fold away FLOAD checks against KNULL. */
719 LJFOLD(EQ FLOAD KNULL
)
720 LJFOLD(NE FLOAD KNULL
)
723 /* But fold all other KNULL compares, since only KNULL is equal to KNULL. */
728 LJFOLD(EQ KINT KINT
) /* Constants are unique, so same refs <==> same value. */
730 LJFOLD(EQ KINT64 KINT64
)
731 LJFOLD(NE KINT64 KINT64
)
736 return CONDFOLD((fins
->op1
== fins
->op2
) ^ (fins
->o
== IR_NE
));
739 /* -- Algebraic shortcuts ------------------------------------------------- */
741 LJFOLD(FPMATH FPMATH IRFPM_FLOOR
)
742 LJFOLD(FPMATH FPMATH IRFPM_CEIL
)
743 LJFOLD(FPMATH FPMATH IRFPM_TRUNC
)
744 LJFOLDF(shortcut_round
)
746 IRFPMathOp op
= (IRFPMathOp
)fleft
->op2
;
747 if (op
== IRFPM_FLOOR
|| op
== IRFPM_CEIL
|| op
== IRFPM_TRUNC
)
748 return LEFTFOLD
; /* round(round_left(x)) = round_left(x) */
753 LJFOLDF(shortcut_left
)
755 return LEFTFOLD
; /* f(g(x)) ==> g(x) */
759 LJFOLDF(shortcut_dropleft
)
762 fins
->op1
= fleft
->op1
; /* abs(neg(x)) ==> abs(x) */
766 /* Note: no safe shortcuts with STRTO and TOSTR ("1e2" ==> +100 ==> "100"). */
770 LJFOLDF(shortcut_leftleft
)
772 PHIBARRIER(fleft
); /* See above. Fold would be ok, but not beneficial. */
773 return fleft
->op1
; /* f(g(x)) ==> x */
776 /* -- FP algebraic simplifications ---------------------------------------- */
778 /* FP arithmetic is tricky -- there's not much to simplify.
779 ** Please note the following common pitfalls before sending "improvements":
780 ** x+0 ==> x is INVALID for x=-0
781 ** 0-x ==> -x is INVALID for x=+0
782 ** x*0 ==> 0 is INVALID for x=-0, x=+-Inf or x=NaN
786 LJFOLDF(simplify_numadd_negx
)
789 fins
->o
= IR_SUB
; /* (-a) + b ==> b - a */
790 fins
->op1
= fins
->op2
;
791 fins
->op2
= fleft
->op1
;
796 LJFOLDF(simplify_numadd_xneg
)
799 fins
->o
= IR_SUB
; /* a + (-b) ==> a - b */
800 fins
->op2
= fright
->op1
;
805 LJFOLDF(simplify_numsub_k
)
807 lua_Number n
= knumright
;
808 if (n
== 0.0) /* x - (+-0) ==> x */
814 LJFOLDF(simplify_numsub_negk
)
817 fins
->op2
= fleft
->op1
; /* (-x) - k ==> (-k) - x */
818 fins
->op1
= (IRRef1
)lj_ir_knum(J
, -knumright
);
823 LJFOLDF(simplify_numsub_xneg
)
826 fins
->o
= IR_ADD
; /* a - (-b) ==> a + b */
827 fins
->op2
= fright
->op1
;
833 LJFOLDF(simplify_nummuldiv_k
)
835 lua_Number n
= knumright
;
836 if (n
== 1.0) { /* x o 1 ==> x */
838 } else if (n
== -1.0) { /* x o -1 ==> -x */
840 fins
->op2
= (IRRef1
)lj_ir_knum_neg(J
);
842 } else if (fins
->o
== IR_MUL
&& n
== 2.0) { /* x * 2 ==> x + x */
844 fins
->op2
= fins
->op1
;
846 } else if (fins
->o
== IR_DIV
) { /* x / 2^k ==> x * 2^-k */
847 uint64_t u
= ir_knum(fright
)->u64
;
848 uint32_t ex
= ((uint32_t)(u
>> 52) & 0x7ff);
849 if ((u
& U64x(000fffff
,ffffffff
)) == 0 && ex
- 1 < 0x7fd) {
850 u
= (u
& ((uint64_t)1 << 63)) | ((uint64_t)(0x7fe - ex
) << 52);
851 fins
->o
= IR_MUL
; /* Multiply by exact reciprocal. */
852 fins
->op2
= lj_ir_knum_u64(J
, u
);
861 LJFOLDF(simplify_nummuldiv_negk
)
864 fins
->op1
= fleft
->op1
; /* (-a) o k ==> a o (-k) */
865 fins
->op2
= (IRRef1
)lj_ir_knum(J
, -knumright
);
871 LJFOLDF(simplify_nummuldiv_negneg
)
875 fins
->op1
= fleft
->op1
; /* (-a) o (-b) ==> a o b */
876 fins
->op2
= fright
->op1
;
881 LJFOLDF(simplify_numpow_xk
)
883 int32_t k
= fright
->i
;
884 TRef ref
= fins
->op1
;
885 if (k
== 0) /* x ^ 0 ==> 1 */
886 return lj_ir_knum_one(J
); /* Result must be a number, not an int. */
887 if (k
== 1) /* x ^ 1 ==> x */
889 if ((uint32_t)(k
+65536) > 2*65536u) /* Limit code explosion. */
891 if (k
< 0) { /* x ^ (-k) ==> (1/x) ^ k. */
892 ref
= emitir(IRTN(IR_DIV
), lj_ir_knum_one(J
), ref
);
895 /* Unroll x^k for 1 <= k <= 65536. */
896 for (; (k
& 1) == 0; k
>>= 1) /* Handle leading zeros. */
897 ref
= emitir(IRTN(IR_MUL
), ref
, ref
);
898 if ((k
>>= 1) != 0) { /* Handle trailing bits. */
899 TRef tmp
= emitir(IRTN(IR_MUL
), ref
, ref
);
900 for (; k
!= 1; k
>>= 1) {
902 ref
= emitir(IRTN(IR_MUL
), ref
, tmp
);
903 tmp
= emitir(IRTN(IR_MUL
), tmp
, tmp
);
905 ref
= emitir(IRTN(IR_MUL
), ref
, tmp
);
911 LJFOLDF(simplify_numpow_kx
)
913 lua_Number n
= knumleft
;
914 if (n
== 2.0) { /* 2.0 ^ i ==> ldexp(1.0, tonum(i)) */
916 #if LJ_TARGET_X86ORX64
917 fins
->op1
= fins
->op2
;
918 fins
->op2
= IRCONV_NUM_INT
;
919 fins
->op2
= (IRRef1
)lj_opt_fold(J
);
921 fins
->op1
= (IRRef1
)lj_ir_knum_one(J
);
928 /* -- Simplify conversions ------------------------------------------------ */
930 LJFOLD(CONV CONV IRCONV_NUM_INT
) /* _NUM */
931 LJFOLDF(shortcut_conv_num_int
)
934 /* Only safe with a guarded conversion to int. */
935 if ((fleft
->op2
& IRCONV_SRCMASK
) == IRT_NUM
&& irt_isguard(fleft
->t
))
936 return fleft
->op1
; /* f(g(x)) ==> x */
940 LJFOLD(CONV CONV IRCONV_INT_NUM
) /* _INT */
941 LJFOLD(CONV CONV IRCONV_U32_NUM
) /* _U32*/
942 LJFOLDF(simplify_conv_int_num
)
944 /* Fold even across PHI to avoid expensive num->int conversions in loop. */
945 if ((fleft
->op2
& IRCONV_SRCMASK
) ==
946 ((fins
->op2
& IRCONV_DSTMASK
) >> IRCONV_DSH
))
951 LJFOLD(CONV CONV IRCONV_I64_NUM
) /* _INT or _U32 */
952 LJFOLD(CONV CONV IRCONV_U64_NUM
) /* _INT or _U32 */
953 LJFOLDF(simplify_conv_i64_num
)
956 if ((fleft
->op2
& IRCONV_SRCMASK
) == IRT_INT
) {
957 /* Reduce to a sign-extension. */
958 fins
->op1
= fleft
->op1
;
959 fins
->op2
= ((IRT_I64
<<5)|IRT_INT
|IRCONV_SEXT
);
961 } else if ((fleft
->op2
& IRCONV_SRCMASK
) == IRT_U32
) {
965 /* Reduce to a zero-extension. */
966 fins
->op1
= fleft
->op1
;
967 fins
->op2
= (IRT_I64
<<5)|IRT_U32
;
974 LJFOLD(CONV CONV IRCONV_INT_I64
) /* _INT or _U32 */
975 LJFOLD(CONV CONV IRCONV_INT_U64
) /* _INT or _U32 */
976 LJFOLD(CONV CONV IRCONV_U32_I64
) /* _INT or _U32 */
977 LJFOLD(CONV CONV IRCONV_U32_U64
) /* _INT or _U32 */
978 LJFOLDF(simplify_conv_int_i64
)
982 src
= (fleft
->op2
& IRCONV_SRCMASK
);
983 if (src
== IRT_INT
|| src
== IRT_U32
) {
984 if (src
== ((fins
->op2
& IRCONV_DSTMASK
) >> IRCONV_DSH
)) {
987 fins
->op2
= ((fins
->op2
& IRCONV_DSTMASK
) | src
);
988 fins
->op1
= fleft
->op1
;
995 LJFOLD(CONV CONV IRCONV_FLOAT_NUM
) /* _FLOAT */
996 LJFOLDF(simplify_conv_flt_num
)
999 if ((fleft
->op2
& IRCONV_SRCMASK
) == IRT_FLOAT
)
1004 /* Shortcut TOBIT + IRT_NUM <- IRT_INT/IRT_U32 conversion. */
1005 LJFOLD(TOBIT CONV KNUM
)
1006 LJFOLDF(simplify_tobit_conv
)
1008 if ((fleft
->op2
& IRCONV_SRCMASK
) == IRT_INT
||
1009 (fleft
->op2
& IRCONV_SRCMASK
) == IRT_U32
) {
1010 /* Fold even across PHI to avoid expensive num->int conversions in loop. */
1011 lua_assert(irt_isnum(fleft
->t
));
1017 /* Shortcut floor/ceil/round + IRT_NUM <- IRT_INT/IRT_U32 conversion. */
1018 LJFOLD(FPMATH CONV IRFPM_FLOOR
)
1019 LJFOLD(FPMATH CONV IRFPM_CEIL
)
1020 LJFOLD(FPMATH CONV IRFPM_TRUNC
)
1021 LJFOLDF(simplify_floor_conv
)
1023 if ((fleft
->op2
& IRCONV_SRCMASK
) == IRT_INT
||
1024 (fleft
->op2
& IRCONV_SRCMASK
) == IRT_U32
)
1029 /* Strength reduction of widening. */
1030 LJFOLD(CONV any IRCONV_I64_INT
)
1031 LJFOLD(CONV any IRCONV_U64_INT
)
1032 LJFOLDF(simplify_conv_sext
)
1034 IRRef ref
= fins
->op1
;
1036 if (!(fins
->op2
& IRCONV_SEXT
))
1039 if (fleft
->o
== IR_XLOAD
&& (irt_isu8(fleft
->t
) || irt_isu16(fleft
->t
)))
1041 if (fleft
->o
== IR_ADD
&& irref_isk(fleft
->op2
)) {
1042 ofs
= (int64_t)IR(fleft
->op2
)->i
;
1045 /* Use scalar evolution analysis results to strength-reduce sign-extension. */
1046 if (ref
== J
->scev
.idx
) {
1047 IRRef lo
= J
->scev
.dir
? J
->scev
.start
: J
->scev
.stop
;
1048 lua_assert(irt_isint(J
->scev
.t
));
1049 if (lo
&& IR(lo
)->i
+ ofs
>= 0) {
1052 /* Eliminate widening. All 32 bit ops do an implicit zero-extension. */
1055 /* Reduce to a (cheaper) zero-extension. */
1056 fins
->op2
&= ~IRCONV_SEXT
;
1064 /* Strength reduction of narrowing. */
1065 LJFOLD(CONV ADD IRCONV_INT_I64
)
1066 LJFOLD(CONV SUB IRCONV_INT_I64
)
1067 LJFOLD(CONV MUL IRCONV_INT_I64
)
1068 LJFOLD(CONV ADD IRCONV_INT_U64
)
1069 LJFOLD(CONV SUB IRCONV_INT_U64
)
1070 LJFOLD(CONV MUL IRCONV_INT_U64
)
1071 LJFOLD(CONV ADD IRCONV_U32_I64
)
1072 LJFOLD(CONV SUB IRCONV_U32_I64
)
1073 LJFOLD(CONV MUL IRCONV_U32_I64
)
1074 LJFOLD(CONV ADD IRCONV_U32_U64
)
1075 LJFOLD(CONV SUB IRCONV_U32_U64
)
1076 LJFOLD(CONV MUL IRCONV_U32_U64
)
1077 LJFOLDF(simplify_conv_narrow
)
1079 IROp op
= (IROp
)fleft
->o
;
1080 IRType t
= irt_type(fins
->t
);
1081 IRRef op1
= fleft
->op1
, op2
= fleft
->op2
, mode
= fins
->op2
;
1083 op1
= emitir(IRTI(IR_CONV
), op1
, mode
);
1084 op2
= emitir(IRTI(IR_CONV
), op2
, mode
);
1085 fins
->ot
= IRT(op
, t
);
1091 /* Special CSE rule for CONV. */
1092 LJFOLD(CONV any any
)
1095 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_CSE
)) {
1096 IRRef op1
= fins
->op1
, op2
= (fins
->op2
& IRCONV_MODEMASK
);
1097 uint8_t guard
= irt_isguard(fins
->t
);
1098 IRRef ref
= J
->chain
[IR_CONV
];
1100 IRIns
*ir
= IR(ref
);
1101 /* Commoning with stronger checks is ok. */
1102 if (ir
->op1
== op1
&& (ir
->op2
& IRCONV_MODEMASK
) == op2
&&
1103 irt_isguard(ir
->t
) >= guard
)
1108 return EMITFOLD
; /* No fallthrough to regular CSE. */
1111 /* FP conversion narrowing. */
1112 LJFOLD(TOBIT ADD KNUM
)
1113 LJFOLD(TOBIT SUB KNUM
)
1114 LJFOLD(CONV ADD IRCONV_INT_NUM
)
1115 LJFOLD(CONV SUB IRCONV_INT_NUM
)
1116 LJFOLD(CONV ADD IRCONV_I64_NUM
)
1117 LJFOLD(CONV SUB IRCONV_I64_NUM
)
1118 LJFOLDF(narrow_convert
)
1121 /* Narrowing ignores PHIs and repeating it inside the loop is not useful. */
1122 if (J
->chain
[IR_LOOP
])
1124 lua_assert(fins
->o
!= IR_CONV
|| (fins
->op2
&IRCONV_CONVMASK
) != IRCONV_TOBIT
);
1125 return lj_opt_narrow_convert(J
);
1128 /* -- Integer algebraic simplifications ----------------------------------- */
1130 LJFOLD(ADD any KINT
)
1131 LJFOLD(ADDOV any KINT
)
1132 LJFOLD(SUBOV any KINT
)
1133 LJFOLDF(simplify_intadd_k
)
1135 if (fright
->i
== 0) /* i o 0 ==> i */
1140 LJFOLD(MULOV any KINT
)
1141 LJFOLDF(simplify_intmul_k
)
1143 if (fright
->i
== 0) /* i * 0 ==> 0 */
1145 if (fright
->i
== 1) /* i * 1 ==> i */
1147 if (fright
->i
== 2) { /* i * 2 ==> i + i */
1149 fins
->op2
= fins
->op1
;
1155 LJFOLD(SUB any KINT
)
1156 LJFOLDF(simplify_intsub_k
)
1158 if (fright
->i
== 0) /* i - 0 ==> i */
1160 fins
->o
= IR_ADD
; /* i - k ==> i + (-k) */
1161 fins
->op2
= (IRRef1
)lj_ir_kint(J
, -fright
->i
); /* Overflow for -2^31 ok. */
1165 LJFOLD(SUB KINT any
)
1166 LJFOLD(SUB KINT64 any
)
1167 LJFOLDF(simplify_intsub_kleft
)
1169 if (fleft
->o
== IR_KINT
? (fleft
->i
== 0) : (ir_kint64(fleft
)->u64
== 0)) {
1170 fins
->o
= IR_NEG
; /* 0 - i ==> -i */
1171 fins
->op1
= fins
->op2
;
1177 LJFOLD(ADD any KINT64
)
1178 LJFOLDF(simplify_intadd_k64
)
1180 if (ir_kint64(fright
)->u64
== 0) /* i + 0 ==> i */
1185 LJFOLD(SUB any KINT64
)
1186 LJFOLDF(simplify_intsub_k64
)
1188 uint64_t k
= ir_kint64(fright
)->u64
;
1189 if (k
== 0) /* i - 0 ==> i */
1191 fins
->o
= IR_ADD
; /* i - k ==> i + (-k) */
1192 fins
->op2
= (IRRef1
)lj_ir_kint64(J
, (uint64_t)-(int64_t)k
);
1196 static TRef
simplify_intmul_k(jit_State
*J
, int32_t k
)
1198 /* Note: many more simplifications are possible, e.g. 2^k1 +- 2^k2.
1199 ** But this is mainly intended for simple address arithmetic.
1200 ** Also it's easier for the backend to optimize the original multiplies.
1202 if (k
== 1) { /* i * 1 ==> i */
1204 } else if ((k
& (k
-1)) == 0) { /* i * 2^k ==> i << k */
1206 fins
->op2
= lj_ir_kint(J
, lj_fls((uint32_t)k
));
1212 LJFOLD(MUL any KINT
)
1213 LJFOLDF(simplify_intmul_k32
)
1215 if (fright
->i
== 0) /* i * 0 ==> 0 */
1217 else if (fright
->i
> 0)
1218 return simplify_intmul_k(J
, fright
->i
);
1222 LJFOLD(MUL any KINT64
)
1223 LJFOLDF(simplify_intmul_k64
)
1225 if (ir_kint64(fright
)->u64
== 0) /* i * 0 ==> 0 */
1226 return INT64FOLD(0);
1228 /* NYI: SPLIT for BSHL and 32 bit backend support. */
1229 else if (ir_kint64(fright
)->u64
< 0x80000000u
)
1230 return simplify_intmul_k(J
, (int32_t)ir_kint64(fright
)->u64
);
1235 LJFOLD(MOD any KINT
)
1236 LJFOLDF(simplify_intmod_k
)
1238 int32_t k
= fright
->i
;
1240 if (k
> 0 && (k
& (k
-1)) == 0) { /* i % (2^k) ==> i & (2^k-1) */
1242 fins
->op2
= lj_ir_kint(J
, k
-1);
1248 LJFOLD(MOD KINT any
)
1249 LJFOLDF(simplify_intmod_kleft
)
1257 LJFOLD(SUBOV any any
)
1258 LJFOLDF(simplify_intsub
)
1260 if (fins
->op1
== fins
->op2
&& !irt_isnum(fins
->t
)) /* i - i ==> 0 */
1261 return irt_is64(fins
->t
) ? INT64FOLD(0) : INTFOLD(0);
1266 LJFOLDF(simplify_intsubadd_leftcancel
)
1268 if (!irt_isnum(fins
->t
)) {
1270 if (fins
->op2
== fleft
->op1
) /* (i + j) - i ==> j */
1272 if (fins
->op2
== fleft
->op2
) /* (i + j) - j ==> i */
1279 LJFOLDF(simplify_intsubsub_leftcancel
)
1281 if (!irt_isnum(fins
->t
)) {
1283 if (fins
->op2
== fleft
->op1
) { /* (i - j) - i ==> 0 - j */
1284 fins
->op1
= (IRRef1
)lj_ir_kint(J
, 0);
1285 fins
->op2
= fleft
->op2
;
1293 LJFOLDF(simplify_intsubsub_rightcancel
)
1295 if (!irt_isnum(fins
->t
)) {
1297 if (fins
->op1
== fright
->op1
) /* i - (i - j) ==> j */
1304 LJFOLDF(simplify_intsubadd_rightcancel
)
1306 if (!irt_isnum(fins
->t
)) {
1308 if (fins
->op1
== fright
->op1
) { /* i - (i + j) ==> 0 - j */
1309 fins
->op2
= fright
->op2
;
1310 fins
->op1
= (IRRef1
)lj_ir_kint(J
, 0);
1313 if (fins
->op1
== fright
->op2
) { /* i - (j + i) ==> 0 - j */
1314 fins
->op2
= fright
->op1
;
1315 fins
->op1
= (IRRef1
)lj_ir_kint(J
, 0);
1323 LJFOLDF(simplify_intsubaddadd_cancel
)
1325 if (!irt_isnum(fins
->t
)) {
1328 if (fleft
->op1
== fright
->op1
) { /* (i + j1) - (i + j2) ==> j1 - j2 */
1329 fins
->op1
= fleft
->op2
;
1330 fins
->op2
= fright
->op2
;
1333 if (fleft
->op1
== fright
->op2
) { /* (i + j1) - (j2 + i) ==> j1 - j2 */
1334 fins
->op1
= fleft
->op2
;
1335 fins
->op2
= fright
->op1
;
1338 if (fleft
->op2
== fright
->op1
) { /* (j1 + i) - (i + j2) ==> j1 - j2 */
1339 fins
->op1
= fleft
->op1
;
1340 fins
->op2
= fright
->op2
;
1343 if (fleft
->op2
== fright
->op2
) { /* (j1 + i) - (j2 + i) ==> j1 - j2 */
1344 fins
->op1
= fleft
->op1
;
1345 fins
->op2
= fright
->op1
;
1352 LJFOLD(BAND any KINT
)
1353 LJFOLD(BAND any KINT64
)
1354 LJFOLDF(simplify_band_k
)
1356 int64_t k
= fright
->o
== IR_KINT
? (int64_t)fright
->i
:
1357 (int64_t)ir_k64(fright
)->u64
;
1358 if (k
== 0) /* i & 0 ==> 0 */
1360 if (k
== -1) /* i & -1 ==> i */
1365 LJFOLD(BOR any KINT
)
1366 LJFOLD(BOR any KINT64
)
1367 LJFOLDF(simplify_bor_k
)
1369 int64_t k
= fright
->o
== IR_KINT
? (int64_t)fright
->i
:
1370 (int64_t)ir_k64(fright
)->u64
;
1371 if (k
== 0) /* i | 0 ==> i */
1373 if (k
== -1) /* i | -1 ==> -1 */
1378 LJFOLD(BXOR any KINT
)
1379 LJFOLD(BXOR any KINT64
)
1380 LJFOLDF(simplify_bxor_k
)
1382 int64_t k
= fright
->o
== IR_KINT
? (int64_t)fright
->i
:
1383 (int64_t)ir_k64(fright
)->u64
;
1384 if (k
== 0) /* i xor 0 ==> i */
1386 if (k
== -1) { /* i xor -1 ==> ~i */
1394 LJFOLD(BSHL any KINT
)
1395 LJFOLD(BSHR any KINT
)
1396 LJFOLD(BSAR any KINT
)
1397 LJFOLD(BROL any KINT
)
1398 LJFOLD(BROR any KINT
)
1399 LJFOLDF(simplify_shift_ik
)
1401 int32_t mask
= irt_is64(fins
->t
) ? 63 : 31;
1402 int32_t k
= (fright
->i
& mask
);
1403 if (k
== 0) /* i o 0 ==> i */
1405 if (k
== 1 && fins
->o
== IR_BSHL
) { /* i << 1 ==> i + i */
1407 fins
->op2
= fins
->op1
;
1410 if (k
!= fright
->i
) { /* i o k ==> i o (k & mask) */
1411 fins
->op2
= (IRRef1
)lj_ir_kint(J
, k
);
1414 #ifndef LJ_TARGET_UNIFYROT
1415 if (fins
->o
== IR_BROR
) { /* bror(i, k) ==> brol(i, (-k)&mask) */
1417 fins
->op2
= (IRRef1
)lj_ir_kint(J
, (-k
)&mask
);
1424 LJFOLD(BSHL any BAND
)
1425 LJFOLD(BSHR any BAND
)
1426 LJFOLD(BSAR any BAND
)
1427 LJFOLD(BROL any BAND
)
1428 LJFOLD(BROR any BAND
)
1429 LJFOLDF(simplify_shift_andk
)
1431 IRIns
*irk
= IR(fright
->op2
);
1433 if ((fins
->o
< IR_BROL
? LJ_TARGET_MASKSHIFT
: LJ_TARGET_MASKROT
) &&
1434 irk
->o
== IR_KINT
) { /* i o (j & mask) ==> i o j */
1435 int32_t mask
= irt_is64(fins
->t
) ? 63 : 31;
1436 int32_t k
= irk
->i
& mask
;
1438 fins
->op2
= fright
->op1
;
1445 LJFOLD(BSHL KINT any
)
1446 LJFOLD(BSHR KINT any
)
1447 LJFOLD(BSHL KINT64 any
)
1448 LJFOLD(BSHR KINT64 any
)
1449 LJFOLDF(simplify_shift1_ki
)
1451 int64_t k
= fleft
->o
== IR_KINT
? (int64_t)fleft
->i
:
1452 (int64_t)ir_k64(fleft
)->u64
;
1453 if (k
== 0) /* 0 o i ==> 0 */
1458 LJFOLD(BSAR KINT any
)
1459 LJFOLD(BROL KINT any
)
1460 LJFOLD(BROR KINT any
)
1461 LJFOLD(BSAR KINT64 any
)
1462 LJFOLD(BROL KINT64 any
)
1463 LJFOLD(BROR KINT64 any
)
1464 LJFOLDF(simplify_shift2_ki
)
1466 int64_t k
= fleft
->o
== IR_KINT
? (int64_t)fleft
->i
:
1467 (int64_t)ir_k64(fleft
)->u64
;
1468 if (k
== 0 || k
== -1) /* 0 o i ==> 0; -1 o i ==> -1 */
1473 LJFOLD(BSHL BAND KINT
)
1474 LJFOLD(BSHR BAND KINT
)
1475 LJFOLD(BROL BAND KINT
)
1476 LJFOLD(BROR BAND KINT
)
1477 LJFOLDF(simplify_shiftk_andk
)
1479 IRIns
*irk
= IR(fleft
->op2
);
1481 if (irk
->o
== IR_KINT
) { /* (i & k1) o k2 ==> (i o k2) & (k1 o k2) */
1482 int32_t k
= kfold_intop(irk
->i
, fright
->i
, (IROp
)fins
->o
);
1483 fins
->op1
= fleft
->op1
;
1484 fins
->op1
= (IRRef1
)lj_opt_fold(J
);
1485 fins
->op2
= (IRRef1
)lj_ir_kint(J
, k
);
1486 fins
->ot
= IRTI(IR_BAND
);
1492 LJFOLD(BAND BSHL KINT
)
1493 LJFOLD(BAND BSHR KINT
)
1494 LJFOLDF(simplify_andk_shiftk
)
1496 IRIns
*irk
= IR(fleft
->op2
);
1497 if (irk
->o
== IR_KINT
&&
1498 kfold_intop(-1, irk
->i
, (IROp
)fleft
->o
) == fright
->i
)
1499 return LEFTFOLD
; /* (i o k1) & k2 ==> i, if (-1 o k1) == k2 */
1503 /* -- Reassociation ------------------------------------------------------- */
1505 LJFOLD(ADD ADD KINT
)
1506 LJFOLD(MUL MUL KINT
)
1507 LJFOLD(BAND BAND KINT
)
1508 LJFOLD(BOR BOR KINT
)
1509 LJFOLD(BXOR BXOR KINT
)
1510 LJFOLDF(reassoc_intarith_k
)
1512 IRIns
*irk
= IR(fleft
->op2
);
1513 if (irk
->o
== IR_KINT
) {
1514 int32_t k
= kfold_intop(irk
->i
, fright
->i
, (IROp
)fins
->o
);
1515 if (k
== irk
->i
) /* (i o k1) o k2 ==> i o k1, if (k1 o k2) == k1. */
1518 fins
->op1
= fleft
->op1
;
1519 fins
->op2
= (IRRef1
)lj_ir_kint(J
, k
);
1520 return RETRYFOLD
; /* (i o k1) o k2 ==> i o (k1 o k2) */
1525 LJFOLD(ADD ADD KINT64
)
1526 LJFOLD(MUL MUL KINT64
)
1527 LJFOLD(BAND BAND KINT64
)
1528 LJFOLD(BOR BOR KINT64
)
1529 LJFOLD(BXOR BXOR KINT64
)
1530 LJFOLDF(reassoc_intarith_k64
)
1532 #if LJ_HASFFI || LJ_64
1533 IRIns
*irk
= IR(fleft
->op2
);
1534 if (irk
->o
== IR_KINT64
) {
1535 uint64_t k
= kfold_int64arith(ir_k64(irk
)->u64
,
1536 ir_k64(fright
)->u64
, (IROp
)fins
->o
);
1538 fins
->op1
= fleft
->op1
;
1539 fins
->op2
= (IRRef1
)lj_ir_kint64(J
, k
);
1540 return RETRYFOLD
; /* (i o k1) o k2 ==> i o (k1 o k2) */
1544 UNUSED(J
); lua_assert(0); return FAILFOLD
;
1550 LJFOLD(BAND BAND any
)
1552 LJFOLDF(reassoc_dup
)
1554 if (fins
->op2
== fleft
->op1
|| fins
->op2
== fleft
->op2
)
1555 return LEFTFOLD
; /* (a o b) o a ==> a o b; (a o b) o b ==> a o b */
1559 LJFOLD(BXOR BXOR any
)
1560 LJFOLDF(reassoc_bxor
)
1563 if (fins
->op2
== fleft
->op1
) /* (a xor b) xor a ==> b */
1565 if (fins
->op2
== fleft
->op2
) /* (a xor b) xor b ==> a */
1570 LJFOLD(BSHL BSHL KINT
)
1571 LJFOLD(BSHR BSHR KINT
)
1572 LJFOLD(BSAR BSAR KINT
)
1573 LJFOLD(BROL BROL KINT
)
1574 LJFOLD(BROR BROR KINT
)
1575 LJFOLDF(reassoc_shift
)
1577 IRIns
*irk
= IR(fleft
->op2
);
1578 PHIBARRIER(fleft
); /* The (shift any KINT) rule covers k2 == 0 and more. */
1579 if (irk
->o
== IR_KINT
) { /* (i o k1) o k2 ==> i o (k1 + k2) */
1580 int32_t mask
= irt_is64(fins
->t
) ? 63 : 31;
1581 int32_t k
= (irk
->i
& mask
) + (fright
->i
& mask
);
1582 if (k
> mask
) { /* Combined shift too wide? */
1583 if (fins
->o
== IR_BSHL
|| fins
->o
== IR_BSHR
)
1584 return mask
== 31 ? INTFOLD(0) : INT64FOLD(0);
1585 else if (fins
->o
== IR_BSAR
)
1590 fins
->op1
= fleft
->op1
;
1591 fins
->op2
= (IRRef1
)lj_ir_kint(J
, k
);
1597 LJFOLD(MIN MIN KNUM
)
1598 LJFOLD(MAX MAX KNUM
)
1599 LJFOLD(MIN MIN KINT
)
1600 LJFOLD(MAX MAX KINT
)
1601 LJFOLDF(reassoc_minmax_k
)
1603 IRIns
*irk
= IR(fleft
->op2
);
1604 if (irk
->o
== IR_KNUM
) {
1605 lua_Number a
= ir_knum(irk
)->n
;
1606 lua_Number y
= lj_vm_foldarith(a
, knumright
, fins
->o
- IR_ADD
);
1607 if (a
== y
) /* (x o k1) o k2 ==> x o k1, if (k1 o k2) == k1. */
1610 fins
->op1
= fleft
->op1
;
1611 fins
->op2
= (IRRef1
)lj_ir_knum(J
, y
);
1612 return RETRYFOLD
; /* (x o k1) o k2 ==> x o (k1 o k2) */
1613 } else if (irk
->o
== IR_KINT
) {
1615 int32_t y
= kfold_intop(a
, fright
->i
, fins
->o
);
1616 if (a
== y
) /* (x o k1) o k2 ==> x o k1, if (k1 o k2) == k1. */
1619 fins
->op1
= fleft
->op1
;
1620 fins
->op2
= (IRRef1
)lj_ir_kint(J
, y
);
1621 return RETRYFOLD
; /* (x o k1) o k2 ==> x o (k1 o k2) */
1628 LJFOLDF(reassoc_minmax_left
)
1630 if (fins
->op2
== fleft
->op1
|| fins
->op2
== fleft
->op2
)
1631 return RIGHTFOLD
; /* (b o1 a) o2 b ==> b; (a o1 b) o2 b ==> b */
1637 LJFOLDF(reassoc_minmax_right
)
1639 if (fins
->op1
== fright
->op1
|| fins
->op1
== fright
->op2
)
1640 return LEFTFOLD
; /* a o2 (a o1 b) ==> a; a o2 (b o1 a) ==> a */
1644 /* -- Array bounds check elimination -------------------------------------- */
1646 /* Eliminate ABC across PHIs to handle t[i-1] forwarding case.
1647 ** ABC(asize, (i+k)+(-k)) ==> ABC(asize, i), but only if it already exists.
1648 ** Could be generalized to (i+k1)+k2 ==> i+(k1+k2), but needs better disambig.
1653 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_ABC
)) {
1654 if (irref_isk(fright
->op2
)) {
1655 IRIns
*add2
= IR(fright
->op1
);
1656 if (add2
->o
== IR_ADD
&& irref_isk(add2
->op2
) &&
1657 IR(fright
->op2
)->i
== -IR(add2
->op2
)->i
) {
1658 IRRef ref
= J
->chain
[IR_ABC
];
1659 IRRef lim
= add2
->op1
;
1660 if (fins
->op1
> lim
) lim
= fins
->op1
;
1662 IRIns
*ir
= IR(ref
);
1663 if (ir
->op1
== fins
->op1
&& ir
->op2
== add2
->op1
)
1673 /* Eliminate ABC for constants.
1674 ** ABC(asize, k1), ABC(asize k2) ==> ABC(asize, max(k1, k2))
1675 ** Drop second ABC if k2 is lower. Otherwise patch first ABC with k2.
1677 LJFOLD(ABC any KINT
)
1680 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_ABC
)) {
1681 IRRef ref
= J
->chain
[IR_ABC
];
1682 IRRef asize
= fins
->op1
;
1683 while (ref
> asize
) {
1684 IRIns
*ir
= IR(ref
);
1685 if (ir
->op1
== asize
&& irref_isk(ir
->op2
)) {
1686 int32_t k
= IR(ir
->op2
)->i
;
1688 ir
->op2
= fins
->op2
;
1693 return EMITFOLD
; /* Already performed CSE. */
1698 /* Eliminate invariant ABC inside loop. */
1702 /* Invariant ABC marked as PTR. Drop if op1 is invariant, too. */
1703 if (!irt_isint(fins
->t
) && fins
->op1
< J
->chain
[IR_LOOP
])
1708 /* -- Commutativity ------------------------------------------------------- */
1710 /* The refs of commutative ops are canonicalized. Lower refs go to the right.
1711 ** Rationale behind this:
1712 ** - It (also) moves constants to the right.
1713 ** - It reduces the number of FOLD rules (e.g. (BOR any KINT) suffices).
1714 ** - It helps CSE to find more matches.
1715 ** - The assembler generates better code with constants at the right.
1720 LJFOLD(ADDOV any any
)
1721 LJFOLD(MULOV any any
)
1724 if (fins
->op1
< fins
->op2
) { /* Move lower ref to the right. */
1725 IRRef1 tmp
= fins
->op1
;
1726 fins
->op1
= fins
->op2
;
1737 /* For non-numbers only: x == x ==> drop; x ~= x ==> fail */
1738 if (fins
->op1
== fins
->op2
&& !irt_isnum(fins
->t
))
1739 return CONDFOLD(fins
->o
== IR_EQ
);
1740 return fold_comm_swap(J
);
1753 /* For non-numbers only: x <=> x ==> drop; x <> x ==> fail */
1754 if (fins
->op1
== fins
->op2
&& !irt_isnum(fins
->t
))
1755 return CONDFOLD((fins
->o
^ (fins
->o
>> 1)) & 1);
1756 if (fins
->op1
< fins
->op2
) { /* Move lower ref to the right. */
1757 IRRef1 tmp
= fins
->op1
;
1758 fins
->op1
= fins
->op2
;
1760 fins
->o
^= 3; /* GT <-> LT, GE <-> LE, does not affect U */
1766 LJFOLD(BAND any any
)
1772 if (fins
->op1
== fins
->op2
) /* x o x ==> x */
1774 return fold_comm_swap(J
);
1777 LJFOLD(BXOR any any
)
1780 if (fins
->op1
== fins
->op2
) /* i xor i ==> 0 */
1781 return irt_is64(fins
->t
) ? INT64FOLD(0) : INTFOLD(0);
1782 return fold_comm_swap(J
);
1785 /* -- Simplification of compound expressions ------------------------------ */
1787 static TRef
kfold_xload(jit_State
*J
, IRIns
*ir
, const void *p
)
1790 switch (irt_type(ir
->t
)) {
1791 case IRT_NUM
: return lj_ir_knum_u64(J
, *(uint64_t *)p
);
1792 case IRT_I8
: k
= (int32_t)*(int8_t *)p
; break;
1793 case IRT_U8
: k
= (int32_t)*(uint8_t *)p
; break;
1794 case IRT_I16
: k
= (int32_t)(int16_t)lj_getu16(p
); break;
1795 case IRT_U16
: k
= (int32_t)(uint16_t)lj_getu16(p
); break;
1796 case IRT_INT
: case IRT_U32
: k
= (int32_t)lj_getu32(p
); break;
1797 case IRT_I64
: case IRT_U64
: return lj_ir_kint64(J
, *(uint64_t *)p
);
1800 return lj_ir_kint(J
, k
);
1803 /* Turn: string.sub(str, a, b) == kstr
1804 ** into: string.byte(str, a) == string.byte(kstr, 1) etc.
1805 ** Note: this creates unaligned XLOADs on x86/x64.
1809 LJFOLDF(merge_eqne_snew_kgc
)
1811 GCstr
*kstr
= ir_kstr(fright
);
1812 int32_t len
= (int32_t)kstr
->len
;
1813 lua_assert(irt_isstr(fins
->t
));
1815 #if LJ_TARGET_UNALIGNED
1816 #define FOLD_SNEW_MAX_LEN 4 /* Handle string lengths 0, 1, 2, 3, 4. */
1817 #define FOLD_SNEW_TYPE8 IRT_I8 /* Creates shorter immediates. */
1819 #define FOLD_SNEW_MAX_LEN 1 /* Handle string lengths 0 or 1. */
1820 #define FOLD_SNEW_TYPE8 IRT_U8 /* Prefer unsigned loads. */
1824 if (len
<= FOLD_SNEW_MAX_LEN
) {
1825 IROp op
= (IROp
)fins
->o
;
1826 IRRef strref
= fleft
->op1
;
1827 lua_assert(IR(strref
)->o
== IR_STRREF
);
1829 emitir(IRTGI(IR_EQ
), fleft
->op2
, lj_ir_kint(J
, len
));
1830 /* Caveat: fins/fleft/fright is no longer valid after emitir. */
1832 /* NE is not expanded since this would need an OR of two conds. */
1833 if (!irref_isk(fleft
->op2
)) /* Only handle the constant length case. */
1835 if (IR(fleft
->op2
)->i
!= len
)
1839 /* A 4 byte load for length 3 is ok -- all strings have an extra NUL. */
1840 uint16_t ot
= (uint16_t)(len
== 1 ? IRT(IR_XLOAD
, FOLD_SNEW_TYPE8
) :
1841 len
== 2 ? IRT(IR_XLOAD
, IRT_U16
) :
1843 TRef tmp
= emitir(ot
, strref
,
1844 IRXLOAD_READONLY
| (len
> 1 ? IRXLOAD_UNALIGNED
: 0));
1845 TRef val
= kfold_xload(J
, IR(tref_ref(tmp
)), strdata(kstr
));
1847 tmp
= emitir(IRTI(IR_BAND
), tmp
,
1848 lj_ir_kint(J
, LJ_ENDIAN_SELECT(0x00ffffff, 0xffffff00)));
1849 fins
->op1
= (IRRef1
)tmp
;
1850 fins
->op2
= (IRRef1
)val
;
1851 fins
->ot
= (IROpT
)IRTGI(op
);
1860 /* -- Loads --------------------------------------------------------------- */
1862 /* Loads cannot be folded or passed on to CSE in general.
1863 ** Alias analysis is needed to check for forwarding opportunities.
1865 ** Caveat: *all* loads must be listed here or they end up at CSE!
1869 LJFOLDX(lj_opt_fwd_aload
)
1871 /* From HREF fwd (see below). Must eliminate, not supported by fwd/backend. */
1873 LJFOLDF(kfold_hload_kkptr
)
1876 lua_assert(ir_kptr(fleft
) == niltvg(J2G(J
)));
1881 LJFOLDX(lj_opt_fwd_hload
)
1884 LJFOLDX(lj_opt_fwd_uload
)
1886 LJFOLD(CALLL any IRCALL_lj_tab_len
)
1887 LJFOLDX(lj_opt_fwd_tab_len
)
1889 /* Upvalue refs are really loads, but there are no corresponding stores.
1890 ** So CSE is ok for them, except for UREFO across a GC step (see below).
1891 ** If the referenced function is const, its upvalue addresses are const, too.
1892 ** This can be used to improve CSE by looking for the same address,
1893 ** even if the upvalues originate from a different function.
1895 LJFOLD(UREFO KGC any
)
1896 LJFOLD(UREFC KGC any
)
1899 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_CSE
)) {
1900 IRRef ref
= J
->chain
[fins
->o
];
1901 GCfunc
*fn
= ir_kfunc(fleft
);
1902 GCupval
*uv
= gco2uv(gcref(fn
->l
.uvptr
[(fins
->op2
>> 8)]));
1904 IRIns
*ir
= IR(ref
);
1905 if (irref_isk(ir
->op1
)) {
1906 GCfunc
*fn2
= ir_kfunc(IR(ir
->op1
));
1907 if (gco2uv(gcref(fn2
->l
.uvptr
[(ir
->op2
>> 8)])) == uv
) {
1908 if (fins
->o
== IR_UREFO
&& gcstep_barrier(J
, ref
))
1919 LJFOLD(HREFK any any
)
1920 LJFOLDX(lj_opt_fwd_hrefk
)
1922 LJFOLD(HREF TNEW any
)
1923 LJFOLDF(fwd_href_tnew
)
1925 if (lj_opt_fwd_href_nokey(J
))
1926 return lj_ir_kkptr(J
, niltvg(J2G(J
)));
1930 LJFOLD(HREF TDUP KPRI
)
1931 LJFOLD(HREF TDUP KGC
)
1932 LJFOLD(HREF TDUP KNUM
)
1933 LJFOLDF(fwd_href_tdup
)
1936 lj_ir_kvalue(J
->L
, &keyv
, fright
);
1937 if (lj_tab_get(J
->L
, ir_ktab(IR(fleft
->op1
)), &keyv
) == niltvg(J2G(J
)) &&
1938 lj_opt_fwd_href_nokey(J
))
1939 return lj_ir_kkptr(J
, niltvg(J2G(J
)));
1943 /* We can safely FOLD/CSE array/hash refs and field loads, since there
1944 ** are no corresponding stores. But we need to check for any NEWREF with
1945 ** an aliased table, as it may invalidate all of the pointers and fields.
1946 ** Only HREF needs the NEWREF check -- AREF and HREFK already depend on
1947 ** FLOADs. And NEWREF itself is treated like a store (see below).
1949 LJFOLD(FLOAD TNEW IRFL_TAB_ASIZE
)
1950 LJFOLDF(fload_tab_tnew_asize
)
1952 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
) && lj_opt_fwd_tptr(J
, fins
->op1
))
1953 return INTFOLD(fleft
->op1
);
1957 LJFOLD(FLOAD TNEW IRFL_TAB_HMASK
)
1958 LJFOLDF(fload_tab_tnew_hmask
)
1960 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
) && lj_opt_fwd_tptr(J
, fins
->op1
))
1961 return INTFOLD((1 << fleft
->op2
)-1);
1965 LJFOLD(FLOAD TDUP IRFL_TAB_ASIZE
)
1966 LJFOLDF(fload_tab_tdup_asize
)
1968 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
) && lj_opt_fwd_tptr(J
, fins
->op1
))
1969 return INTFOLD((int32_t)ir_ktab(IR(fleft
->op1
))->asize
);
1973 LJFOLD(FLOAD TDUP IRFL_TAB_HMASK
)
1974 LJFOLDF(fload_tab_tdup_hmask
)
1976 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
) && lj_opt_fwd_tptr(J
, fins
->op1
))
1977 return INTFOLD((int32_t)ir_ktab(IR(fleft
->op1
))->hmask
);
1981 LJFOLD(HREF any any
)
1982 LJFOLD(FLOAD any IRFL_TAB_ARRAY
)
1983 LJFOLD(FLOAD any IRFL_TAB_NODE
)
1984 LJFOLD(FLOAD any IRFL_TAB_ASIZE
)
1985 LJFOLD(FLOAD any IRFL_TAB_HMASK
)
1986 LJFOLDF(fload_tab_ah
)
1988 TRef tr
= lj_opt_cse(J
);
1989 return lj_opt_fwd_tptr(J
, tref_ref(tr
)) ? tr
: EMITFOLD
;
1992 /* Strings are immutable, so we can safely FOLD/CSE the related FLOAD. */
1993 LJFOLD(FLOAD KGC IRFL_STR_LEN
)
1994 LJFOLDF(fload_str_len_kgc
)
1996 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
))
1997 return INTFOLD((int32_t)ir_kstr(fleft
)->len
);
2001 LJFOLD(FLOAD SNEW IRFL_STR_LEN
)
2002 LJFOLDF(fload_str_len_snew
)
2004 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
)) {
2011 /* The C type ID of cdata objects is immutable. */
2012 LJFOLD(FLOAD KGC IRFL_CDATA_CTYPEID
)
2013 LJFOLDF(fload_cdata_typeid_kgc
)
2015 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
))
2016 return INTFOLD((int32_t)ir_kcdata(fleft
)->ctypeid
);
2020 /* Get the contents of immutable cdata objects. */
2021 LJFOLD(FLOAD KGC IRFL_CDATA_PTR
)
2022 LJFOLD(FLOAD KGC IRFL_CDATA_INT
)
2023 LJFOLD(FLOAD KGC IRFL_CDATA_INT64
)
2024 LJFOLDF(fload_cdata_int64_kgc
)
2026 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
)) {
2027 void *p
= cdataptr(ir_kcdata(fleft
));
2028 if (irt_is64(fins
->t
))
2029 return INT64FOLD(*(uint64_t *)p
);
2031 return INTFOLD(*(int32_t *)p
);
2036 LJFOLD(FLOAD CNEW IRFL_CDATA_CTYPEID
)
2037 LJFOLD(FLOAD CNEWI IRFL_CDATA_CTYPEID
)
2038 LJFOLDF(fload_cdata_typeid_cnew
)
2040 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
))
2041 return fleft
->op1
; /* No PHI barrier needed. CNEW/CNEWI op1 is const. */
2045 /* Pointer, int and int64 cdata objects are immutable. */
2046 LJFOLD(FLOAD CNEWI IRFL_CDATA_PTR
)
2047 LJFOLD(FLOAD CNEWI IRFL_CDATA_INT
)
2048 LJFOLD(FLOAD CNEWI IRFL_CDATA_INT64
)
2049 LJFOLDF(fload_cdata_ptr_int64_cnew
)
2051 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_FOLD
))
2052 return fleft
->op2
; /* Fold even across PHI to avoid allocations. */
2056 LJFOLD(FLOAD any IRFL_STR_LEN
)
2057 LJFOLD(FLOAD any IRFL_CDATA_CTYPEID
)
2058 LJFOLD(FLOAD any IRFL_CDATA_PTR
)
2059 LJFOLD(FLOAD any IRFL_CDATA_INT
)
2060 LJFOLD(FLOAD any IRFL_CDATA_INT64
)
2061 LJFOLD(VLOAD any any
) /* Vararg loads have no corresponding stores. */
2064 /* All other field loads need alias analysis. */
2065 LJFOLD(FLOAD any any
)
2066 LJFOLDX(lj_opt_fwd_fload
)
2068 /* This is for LOOP only. Recording handles SLOADs internally. */
2069 LJFOLD(SLOAD any any
)
2072 if ((fins
->op2
& IRSLOAD_FRAME
)) {
2073 TRef tr
= lj_opt_cse(J
);
2074 return tref_ref(tr
) < J
->chain
[IR_RETF
] ? EMITFOLD
: tr
;
2076 lua_assert(J
->slot
[fins
->op1
] != 0);
2077 return J
->slot
[fins
->op1
];
2081 /* Only fold for KKPTR. The pointer _and_ the contents must be const. */
2082 LJFOLD(XLOAD KKPTR any
)
2085 TRef tr
= kfold_xload(J
, fins
, ir_kptr(fleft
));
2086 return tr
? tr
: NEXTFOLD
;
2089 LJFOLD(XLOAD any any
)
2090 LJFOLDX(lj_opt_fwd_xload
)
2092 /* -- Write barriers ------------------------------------------------------ */
2094 /* Write barriers are amenable to CSE, but not across any incremental
2097 ** The same logic applies to open upvalue references, because a stack
2098 ** may be resized during a GC step (not the current stack, but maybe that
2102 LJFOLD(OBAR any any
)
2103 LJFOLD(UREFO any any
)
2104 LJFOLDF(barrier_tab
)
2106 TRef tr
= lj_opt_cse(J
);
2107 if (gcstep_barrier(J
, tref_ref(tr
))) /* CSE across GC step? */
2108 return EMITFOLD
; /* Raw emit. Assumes fins is left intact by CSE. */
2114 LJFOLDF(barrier_tnew_tdup
)
2116 /* New tables are always white and never need a barrier. */
2117 if (fins
->op1
< J
->chain
[IR_LOOP
]) /* Except across a GC step. */
2122 /* -- Stores and allocations ---------------------------------------------- */
2124 /* Stores and allocations cannot be folded or passed on to CSE in general.
2125 ** But some stores can be eliminated with dead-store elimination (DSE).
2127 ** Caveat: *all* stores and allocs must be listed here or they end up at CSE!
2130 LJFOLD(ASTORE any any
)
2131 LJFOLD(HSTORE any any
)
2132 LJFOLDX(lj_opt_dse_ahstore
)
2134 LJFOLD(USTORE any any
)
2135 LJFOLDX(lj_opt_dse_ustore
)
2137 LJFOLD(FSTORE any any
)
2138 LJFOLDX(lj_opt_dse_fstore
)
2140 LJFOLD(XSTORE any any
)
2141 LJFOLDX(lj_opt_dse_xstore
)
2143 LJFOLD(NEWREF any any
) /* Treated like a store. */
2144 LJFOLD(CALLS any any
)
2145 LJFOLD(CALLL any any
) /* Safeguard fallback. */
2146 LJFOLD(CALLXS any any
)
2148 LJFOLD(RETF any any
) /* Modifies BASE. */
2149 LJFOLD(TNEW any any
)
2151 LJFOLD(CNEW any any
)
2152 LJFOLD(XSNEW any any
)
2155 /* ------------------------------------------------------------------------ */
2157 /* Every entry in the generated hash table is a 32 bit pattern:
2159 ** xxxxxxxx iiiiiii lllllll rrrrrrrrrr
2161 ** xxxxxxxx = 8 bit index into fold function table
2162 ** iiiiiii = 7 bit folded instruction opcode
2163 ** lllllll = 7 bit left instruction opcode
2164 ** rrrrrrrrrr = 8 bit right instruction opcode or 10 bits from literal field
2167 #include "lj_folddef.h"
2169 /* ------------------------------------------------------------------------ */
2171 /* Fold IR instruction. */
2172 TRef LJ_FASTCALL
lj_opt_fold(jit_State
*J
)
2177 if (LJ_UNLIKELY((J
->flags
& JIT_F_OPT_MASK
) != JIT_F_OPT_DEFAULT
)) {
2178 lua_assert(((JIT_F_OPT_FOLD
|JIT_F_OPT_FWD
|JIT_F_OPT_CSE
|JIT_F_OPT_DSE
) |
2179 JIT_F_OPT_DEFAULT
) == JIT_F_OPT_DEFAULT
);
2180 /* Folding disabled? Chain to CSE, but not for loads/stores/allocs. */
2181 if (!(J
->flags
& JIT_F_OPT_FOLD
) && irm_kind(lj_ir_mode
[fins
->o
]) == IRM_N
)
2182 return lj_opt_cse(J
);
2184 /* No FOLD, forwarding or CSE? Emit raw IR for loads, except for SLOAD. */
2185 if ((J
->flags
& (JIT_F_OPT_FOLD
|JIT_F_OPT_FWD
|JIT_F_OPT_CSE
)) !=
2186 (JIT_F_OPT_FOLD
|JIT_F_OPT_FWD
|JIT_F_OPT_CSE
) &&
2187 irm_kind(lj_ir_mode
[fins
->o
]) == IRM_L
&& fins
->o
!= IR_SLOAD
)
2188 return lj_ir_emit(J
);
2190 /* No FOLD or DSE? Emit raw IR for stores. */
2191 if ((J
->flags
& (JIT_F_OPT_FOLD
|JIT_F_OPT_DSE
)) !=
2192 (JIT_F_OPT_FOLD
|JIT_F_OPT_DSE
) &&
2193 irm_kind(lj_ir_mode
[fins
->o
]) == IRM_S
)
2194 return lj_ir_emit(J
);
2197 /* Fold engine start/retry point. */
2199 /* Construct key from opcode and operand opcodes (unless literal/none). */
2200 key
= ((uint32_t)fins
->o
<< 17);
2201 if (fins
->op1
>= J
->cur
.nk
) {
2202 key
+= (uint32_t)IR(fins
->op1
)->o
<< 10;
2203 *fleft
= *IR(fins
->op1
);
2205 if (fins
->op2
>= J
->cur
.nk
) {
2206 key
+= (uint32_t)IR(fins
->op2
)->o
;
2207 *fright
= *IR(fins
->op2
);
2209 key
+= (fins
->op2
& 0x3ffu
); /* Literal mask. Must include IRCONV_*MASK. */
2212 /* Check for a match in order from most specific to least specific. */
2215 uint32_t k
= key
| (any
& 0x1ffff);
2216 uint32_t h
= fold_hashkey(k
);
2217 uint32_t fh
= fold_hash
[h
]; /* Lookup key in semi-perfect hash table. */
2218 if ((fh
& 0xffffff) == k
|| (fh
= fold_hash
[h
+1], (fh
& 0xffffff) == k
)) {
2219 ref
= (IRRef
)tref_ref(fold_func
[fh
>> 24](J
));
2220 if (ref
!= NEXTFOLD
)
2223 if (any
== 0xfffff) /* Exhausted folding. Pass on to CSE. */
2224 return lj_opt_cse(J
);
2225 any
= (any
| (any
>> 10)) ^ 0xffc00;
2228 /* Return value processing, ordered by frequency. */
2229 if (LJ_LIKELY(ref
>= MAX_FOLD
))
2230 return TREF(ref
, irt_t(IR(ref
)->t
));
2231 if (ref
== RETRYFOLD
)
2233 if (ref
== KINTFOLD
)
2234 return lj_ir_kint(J
, fins
->i
);
2235 if (ref
== FAILFOLD
)
2236 lj_trace_err(J
, LJ_TRERR_GFAIL
);
2237 lua_assert(ref
== DROPFOLD
);
2241 /* -- Common-Subexpression Elimination ------------------------------------ */
2243 /* CSE an IR instruction. This is very fast due to the skip-list chains. */
2244 TRef LJ_FASTCALL
lj_opt_cse(jit_State
*J
)
2246 /* Avoid narrow to wide store-to-load forwarding stall */
2247 IRRef2 op12
= (IRRef2
)fins
->op1
+ ((IRRef2
)fins
->op2
<< 16);
2249 if (LJ_LIKELY(J
->flags
& JIT_F_OPT_CSE
)) {
2250 /* Limited search for same operands in per-opcode chain. */
2251 IRRef ref
= J
->chain
[op
];
2252 IRRef lim
= fins
->op1
;
2253 if (fins
->op2
> lim
) lim
= fins
->op2
; /* Relies on lit < REF_BIAS. */
2255 if (IR(ref
)->op12
== op12
)
2256 return TREF(ref
, irt_t(IR(ref
)->t
)); /* Common subexpression found. */
2257 ref
= IR(ref
)->prev
;
2260 /* Otherwise emit IR (inlined for speed). */
2262 IRRef ref
= lj_ir_nextins(J
);
2263 IRIns
*ir
= IR(ref
);
2264 ir
->prev
= J
->chain
[op
];
2266 J
->chain
[op
] = (IRRef1
)ref
;
2268 J
->guardemit
.irt
|= fins
->t
.irt
;
2269 return TREF(ref
, irt_t((ir
->t
= fins
->t
)));
2273 /* CSE with explicit search limit. */
2274 TRef LJ_FASTCALL
lj_opt_cselim(jit_State
*J
, IRRef lim
)
2276 IRRef ref
= J
->chain
[fins
->o
];
2277 IRRef2 op12
= (IRRef2
)fins
->op1
+ ((IRRef2
)fins
->op2
<< 16);
2279 if (IR(ref
)->op12
== op12
)
2281 ref
= IR(ref
)->prev
;
2283 return lj_ir_emit(J
);
2286 /* ------------------------------------------------------------------------ */