1/* This file contains the definitions and documentation for the
2   Register Transfer Expressions (rtx's) that make up the
3   Register Transfer Language (rtl) used in the Back End of the GNU compiler.
4   Copyright (C) 1987, 1988, 1992, 1994, 1995, 1997, 1998, 1999, 2000, 2004,
5   2005, 2006
6   Free Software Foundation, Inc.
7
8This file is part of GCC.
9
10GCC is free software; you can redistribute it and/or modify it under
11the terms of the GNU General Public License as published by the Free
12Software Foundation; either version 2, or (at your option) any later
13version.
14
15GCC is distributed in the hope that it will be useful, but WITHOUT ANY
16WARRANTY; without even the implied warranty of MERCHANTABILITY or
17FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
18for more details.
19
20You should have received a copy of the GNU General Public License
21along with GCC; see the file COPYING.  If not, write to the Free
22Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
2302110-1301, USA.  */
24
25
26/* Expression definitions and descriptions for all targets are in this file.
27   Some will not be used for some targets.
28
29   The fields in the cpp macro call "DEF_RTL_EXPR()"
30   are used to create declarations in the C source of the compiler.
31
32   The fields are:
33
34   1.  The internal name of the rtx used in the C source.
35   It is a tag in the enumeration "enum rtx_code" defined in "rtl.h".
36   By convention these are in UPPER_CASE.
37
38   2.  The name of the rtx in the external ASCII format read by
39   read_rtx(), and printed by print_rtx().
40   These names are stored in rtx_name[].
41   By convention these are the internal (field 1) names in lower_case.
42
43   3.  The print format, and type of each rtx->u.fld[] (field) in this rtx.
44   These formats are stored in rtx_format[].
45   The meaning of the formats is documented in front of this array in rtl.c
46
47   4.  The class of the rtx.  These are stored in rtx_class and are accessed
48   via the GET_RTX_CLASS macro.  They are defined as follows:
49
50     RTX_CONST_OBJ
51         an rtx code that can be used to represent a constant object
52         (e.g, CONST_INT)
53     RTX_OBJ
54         an rtx code that can be used to represent an object (e.g, REG, MEM)
55     RTX_COMPARE
56         an rtx code for a comparison (e.g, LT, GT)
57     RTX_COMM_COMPARE
58         an rtx code for a commutative comparison (e.g, EQ, NE, ORDERED)
59     RTX_UNARY
60         an rtx code for a unary arithmetic expression (e.g, NEG, NOT)
61     RTX_COMM_ARITH
62         an rtx code for a commutative binary operation (e.g,, PLUS, MULT)
63     RTX_TERNARY
64         an rtx code for a non-bitfield three input operation (IF_THEN_ELSE)
65     RTX_BIN_ARITH
66         an rtx code for a non-commutative binary operation (e.g., MINUS, DIV)
67     RTX_BITFIELD_OPS
68         an rtx code for a bit-field operation (ZERO_EXTRACT, SIGN_EXTRACT)
69     RTX_INSN
70         an rtx code for a machine insn (INSN, JUMP_INSN, CALL_INSN)
71     RTX_MATCH
72         an rtx code for something that matches in insns (e.g, MATCH_DUP)
73     RTX_AUTOINC
74         an rtx code for autoincrement addressing modes (e.g. POST_DEC)
75     RTX_EXTRA
76         everything else
77
78   All of the expressions that appear only in machine descriptions,
79   not in RTL used by the compiler itself, are at the end of the file.  */
80
81/* Unknown, or no such operation; the enumeration constant should have
82   value zero.  */
83DEF_RTL_EXPR(UNKNOWN, "UnKnown", "*", RTX_EXTRA)
84
85/* ---------------------------------------------------------------------
86   Expressions used in constructing lists.
87   --------------------------------------------------------------------- */
88
89/* a linked list of expressions */
90DEF_RTL_EXPR(EXPR_LIST, "expr_list", "ee", RTX_EXTRA)
91
92/* a linked list of instructions.
93   The insns are represented in print by their uids.  */
94DEF_RTL_EXPR(INSN_LIST, "insn_list", "ue", RTX_EXTRA)
95
96/* a linked list of dependencies.
97   The insns are represented in print by their uids.
98   Operand 2 is the status of a dependence (see sched-int.h for more).  */
99DEF_RTL_EXPR(DEPS_LIST, "deps_list", "uei", RTX_EXTRA)
100
101/* SEQUENCE appears in the result of a `gen_...' function
102   for a DEFINE_EXPAND that wants to make several insns.
103   Its elements are the bodies of the insns that should be made.
104   `emit_insn' takes the SEQUENCE apart and makes separate insns.  */
105DEF_RTL_EXPR(SEQUENCE, "sequence", "E", RTX_EXTRA)
106
107/* Refers to the address of its argument.  This is only used in alias.c.  */
108DEF_RTL_EXPR(ADDRESS, "address", "e", RTX_MATCH)
109
110/* ----------------------------------------------------------------------
111   Expression types used for things in the instruction chain.
112
113   All formats must start with "iuu" to handle the chain.
114   Each insn expression holds an rtl instruction and its semantics
115   during back-end processing.
116   See macros's in "rtl.h" for the meaning of each rtx->u.fld[].
117
118   ---------------------------------------------------------------------- */
119
120/* An instruction that cannot jump.  */
121DEF_RTL_EXPR(INSN, "insn", "iuuBieiee", RTX_INSN)
122
123/* An instruction that can possibly jump.
124   Fields ( rtx->u.fld[] ) have exact same meaning as INSN's.  */
125DEF_RTL_EXPR(JUMP_INSN, "jump_insn", "iuuBieiee0", RTX_INSN)
126
127/* An instruction that can possibly call a subroutine
128   but which will not change which instruction comes next
129   in the current function.
130   Field ( rtx->u.fld[9] ) is CALL_INSN_FUNCTION_USAGE.
131   All other fields ( rtx->u.fld[] ) have exact same meaning as INSN's.  */
132DEF_RTL_EXPR(CALL_INSN, "call_insn", "iuuBieieee", RTX_INSN)
133
134/* A marker that indicates that control will not flow through.  */
135DEF_RTL_EXPR(BARRIER, "barrier", "iuu000000", RTX_EXTRA)
136
137/* Holds a label that is followed by instructions.
138   Operand:
139   4: is used in jump.c for the use-count of the label.
140   5: is used in flow.c to point to the chain of label_ref's to this label.
141   6: is a number that is unique in the entire compilation.
142   APPLE LOCAL begin for-fsf-4_4 3274130 5295549
143   7: is the user-given name of the label, if any.
144   8: is the alignment of the label, made up of two parts,
145      LABEL_ALIGNMENT and LABEL_MAX_SKIP.  */
146DEF_RTL_EXPR(CODE_LABEL, "code_label", "iuuB00isi", RTX_EXTRA)
147
148/* APPLE LOCAL end for-fsf-4_4 3274130 5295549 */ \
149#ifdef USE_MAPPED_LOCATION
150/* Say where in the code a source line starts, for symbol table's sake.
151   Operand:
152   4: unused if line number > 0, note-specific data otherwise.
153   5: line number if > 0, enum note_insn otherwise.
154   6: CODE_LABEL_NUMBER if line number == NOTE_INSN_DELETED_LABEL.  */
155#else
156/* Say where in the code a source line starts, for symbol table's sake.
157   Operand:
158   4: filename, if line number > 0, note-specific data otherwise.
159   5: line number if > 0, enum note_insn otherwise.
160   6: unique number if line number == note_insn_deleted_label.  */
161#endif
162DEF_RTL_EXPR(NOTE, "note", "iuuB0ni", RTX_EXTRA)
163
164/* ----------------------------------------------------------------------
165   Top level constituents of INSN, JUMP_INSN and CALL_INSN.
166   ---------------------------------------------------------------------- */
167
168/* Conditionally execute code.
169   Operand 0 is the condition that if true, the code is executed.
170   Operand 1 is the code to be executed (typically a SET).
171
172   Semantics are that there are no side effects if the condition
173   is false.  This pattern is created automatically by the if_convert
174   pass run after reload or by target-specific splitters.  */
175DEF_RTL_EXPR(COND_EXEC, "cond_exec", "ee", RTX_EXTRA)
176
177/* Several operations to be done in parallel (perhaps under COND_EXEC).  */
178DEF_RTL_EXPR(PARALLEL, "parallel", "E", RTX_EXTRA)
179
180/* A string that is passed through to the assembler as input.
181     One can obviously pass comments through by using the
182     assembler comment syntax.
183     These occur in an insn all by themselves as the PATTERN.
184     They also appear inside an ASM_OPERANDS
185     as a convenient way to hold a string.  */
186DEF_RTL_EXPR(ASM_INPUT, "asm_input", "s", RTX_EXTRA)
187
188#ifdef USE_MAPPED_LOCATION
189/* An assembler instruction with operands.
190   1st operand is the instruction template.
191   2nd operand is the constraint for the output.
192   3rd operand is the number of the output this expression refers to.
193     When an insn stores more than one value, a separate ASM_OPERANDS
194     is made for each output; this integer distinguishes them.
195   4th is a vector of values of input operands.
196   5th is a vector of modes and constraints for the input operands.
197     Each element is an ASM_INPUT containing a constraint string
198     and whose mode indicates the mode of the input operand.
199   6th is the source line number.  */
200DEF_RTL_EXPR(ASM_OPERANDS, "asm_operands", "ssiEEi", RTX_EXTRA)
201#else
202/* An assembler instruction with operands.
203   1st operand is the instruction template.
204   2nd operand is the constraint for the output.
205   3rd operand is the number of the output this expression refers to.
206     When an insn stores more than one value, a separate ASM_OPERANDS
207     is made for each output; this integer distinguishes them.
208   4th is a vector of values of input operands.
209   5th is a vector of modes and constraints for the input operands.
210     Each element is an ASM_INPUT containing a constraint string
211     and whose mode indicates the mode of the input operand.
212   6th is the name of the containing source file.
213   7th is the source line number.  */
214DEF_RTL_EXPR(ASM_OPERANDS, "asm_operands", "ssiEEsi", RTX_EXTRA)
215#endif
216
217/* A machine-specific operation.
218   1st operand is a vector of operands being used by the operation so that
219     any needed reloads can be done.
220   2nd operand is a unique value saying which of a number of machine-specific
221     operations is to be performed.
222   (Note that the vector must be the first operand because of the way that
223   genrecog.c record positions within an insn.)
224   This can occur all by itself in a PATTERN, as a component of a PARALLEL,
225   or inside an expression.  */
226DEF_RTL_EXPR(UNSPEC, "unspec", "Ei", RTX_EXTRA)
227
228/* Similar, but a volatile operation and one which may trap.  */
229DEF_RTL_EXPR(UNSPEC_VOLATILE, "unspec_volatile", "Ei", RTX_EXTRA)
230
231/* Vector of addresses, stored as full words.  */
232/* Each element is a LABEL_REF to a CODE_LABEL whose address we want.  */
233DEF_RTL_EXPR(ADDR_VEC, "addr_vec", "E", RTX_EXTRA)
234
235/* Vector of address differences X0 - BASE, X1 - BASE, ...
236   First operand is BASE; the vector contains the X's.
237   The machine mode of this rtx says how much space to leave
238   for each difference and is adjusted by branch shortening if
239   CASE_VECTOR_SHORTEN_MODE is defined.
240   The third and fourth operands store the target labels with the
241   minimum and maximum addresses respectively.
242   The fifth operand stores flags for use by branch shortening.
243  Set at the start of shorten_branches:
244   min_align: the minimum alignment for any of the target labels.
245   base_after_vec: true iff BASE is after the ADDR_DIFF_VEC.
246   min_after_vec: true iff minimum addr target label is after the ADDR_DIFF_VEC.
247   max_after_vec: true iff maximum addr target label is after the ADDR_DIFF_VEC.
248   min_after_base: true iff minimum address target label is after BASE.
249   max_after_base: true iff maximum address target label is after BASE.
250  Set by the actual branch shortening process:
251   offset_unsigned: true iff offsets have to be treated as unsigned.
252   scale: scaling that is necessary to make offsets fit into the mode.
253
254   The third, fourth and fifth operands are only valid when
255   CASE_VECTOR_SHORTEN_MODE is defined, and only in an optimizing
256   compilations.  */
257
258DEF_RTL_EXPR(ADDR_DIFF_VEC, "addr_diff_vec", "eEee0", RTX_EXTRA)
259
260/* Memory prefetch, with attributes supported on some targets.
261   Operand 1 is the address of the memory to fetch.
262   Operand 2 is 1 for a write access, 0 otherwise.
263   Operand 3 is the level of temporal locality; 0 means there is no
264   temporal locality and 1, 2, and 3 are for increasing levels of temporal
265   locality.
266
267   The attributes specified by operands 2 and 3 are ignored for targets
268   whose prefetch instructions do not support them.  */
269DEF_RTL_EXPR(PREFETCH, "prefetch", "eee", RTX_EXTRA)
270
271/* ----------------------------------------------------------------------
272   At the top level of an instruction (perhaps under PARALLEL).
273   ---------------------------------------------------------------------- */
274
275/* Assignment.
276   Operand 1 is the location (REG, MEM, PC, CC0 or whatever) assigned to.
277   Operand 2 is the value stored there.
278   ALL assignment must use SET.
279   Instructions that do multiple assignments must use multiple SET,
280   under PARALLEL.  */
281DEF_RTL_EXPR(SET, "set", "ee", RTX_EXTRA)
282
283/* Indicate something is used in a way that we don't want to explain.
284   For example, subroutine calls will use the register
285   in which the static chain is passed.  */
286DEF_RTL_EXPR(USE, "use", "e", RTX_EXTRA)
287
288/* Indicate something is clobbered in a way that we don't want to explain.
289   For example, subroutine calls will clobber some physical registers
290   (the ones that are by convention not saved).  */
291DEF_RTL_EXPR(CLOBBER, "clobber", "e", RTX_EXTRA)
292
293/* Call a subroutine.
294   Operand 1 is the address to call.
295   Operand 2 is the number of arguments.  */
296
297DEF_RTL_EXPR(CALL, "call", "ee", RTX_EXTRA)
298
299/* Return from a subroutine.  */
300
301DEF_RTL_EXPR(RETURN, "return", "", RTX_EXTRA)
302
303/* Conditional trap.
304   Operand 1 is the condition.
305   Operand 2 is the trap code.
306   For an unconditional trap, make the condition (const_int 1).  */
307DEF_RTL_EXPR(TRAP_IF, "trap_if", "ee", RTX_EXTRA)
308
309/* Placeholder for _Unwind_Resume before we know if a function call
310   or a branch is needed.  Operand 1 is the exception region from
311   which control is flowing.  */
312DEF_RTL_EXPR(RESX, "resx", "i", RTX_EXTRA)
313
314/* ----------------------------------------------------------------------
315   Primitive values for use in expressions.
316   ---------------------------------------------------------------------- */
317
318/* numeric integer constant */
319DEF_RTL_EXPR(CONST_INT, "const_int", "w", RTX_CONST_OBJ)
320
321/* numeric floating point constant.
322   Operands hold the value.  They are all 'w' and there may be from 2 to 6;
323   see real.h.  */
324DEF_RTL_EXPR(CONST_DOUBLE, "const_double", CONST_DOUBLE_FORMAT, RTX_CONST_OBJ)
325
326/* Describes a vector constant.  */
327DEF_RTL_EXPR(CONST_VECTOR, "const_vector", "E", RTX_CONST_OBJ)
328
329/* String constant.  Used for attributes in machine descriptions and
330   for special cases in DWARF2 debug output.  NOT used for source-
331   language string constants.  */
332DEF_RTL_EXPR(CONST_STRING, "const_string", "s", RTX_OBJ)
333
334/* This is used to encapsulate an expression whose value is constant
335   (such as the sum of a SYMBOL_REF and a CONST_INT) so that it will be
336   recognized as a constant operand rather than by arithmetic instructions.  */
337
338DEF_RTL_EXPR(CONST, "const", "e", RTX_CONST_OBJ)
339
340/* program counter.  Ordinary jumps are represented
341   by a SET whose first operand is (PC).  */
342DEF_RTL_EXPR(PC, "pc", "", RTX_OBJ)
343
344/* Used in the cselib routines to describe a value.  Objects of this
345   kind are only allocated in cselib.c, in an alloc pool instead of
346   in GC memory.  The only operand of a VALUE is a cselib_val_struct.  */
347DEF_RTL_EXPR(VALUE, "value", "0", RTX_OBJ)
348
349/* A register.  The "operand" is the register number, accessed with
350   the REGNO macro.  If this number is less than FIRST_PSEUDO_REGISTER
351   than a hardware register is being referred to.  The second operand
352   holds the original register number - this will be different for a
353   pseudo register that got turned into a hard register.  The third
354   operand points to a reg_attrs structure.
355   This rtx needs to have as many (or more) fields as a MEM, since we
356   can change REG rtx's into MEMs during reload.  */
357DEF_RTL_EXPR(REG, "reg", "i00", RTX_OBJ)
358
359/* A scratch register.  This represents a register used only within a
360   single insn.  It will be turned into a REG during register allocation
361   or reload unless the constraint indicates that the register won't be
362   needed, in which case it can remain a SCRATCH.  This code is
363   marked as having one operand so it can be turned into a REG.  */
364DEF_RTL_EXPR(SCRATCH, "scratch", "0", RTX_OBJ)
365
366/* One word of a multi-word value.
367   The first operand is the complete value; the second says which word.
368   The WORDS_BIG_ENDIAN flag controls whether word number 0
369   (as numbered in a SUBREG) is the most or least significant word.
370
371   This is also used to refer to a value in a different machine mode.
372   For example, it can be used to refer to a SImode value as if it were
373   Qimode, or vice versa.  Then the word number is always 0.  */
374DEF_RTL_EXPR(SUBREG, "subreg", "ei", RTX_EXTRA)
375
376/* This one-argument rtx is used for move instructions
377   that are guaranteed to alter only the low part of a destination.
378   Thus, (SET (SUBREG:HI (REG...)) (MEM:HI ...))
379   has an unspecified effect on the high part of REG,
380   but (SET (STRICT_LOW_PART (SUBREG:HI (REG...))) (MEM:HI ...))
381   is guaranteed to alter only the bits of REG that are in HImode.
382
383   The actual instruction used is probably the same in both cases,
384   but the register constraints may be tighter when STRICT_LOW_PART
385   is in use.  */
386
387DEF_RTL_EXPR(STRICT_LOW_PART, "strict_low_part", "e", RTX_EXTRA)
388
389/* (CONCAT a b) represents the virtual concatenation of a and b
390   to make a value that has as many bits as a and b put together.
391   This is used for complex values.  Normally it appears only
392   in DECL_RTLs and during RTL generation, but not in the insn chain.  */
393DEF_RTL_EXPR(CONCAT, "concat", "ee", RTX_OBJ)
394
395/* A memory location; operand is the address.  The second operand is the
396   alias set to which this MEM belongs.  We use `0' instead of `w' for this
397   field so that the field need not be specified in machine descriptions.  */
398DEF_RTL_EXPR(MEM, "mem", "e0", RTX_OBJ)
399
400/* Reference to an assembler label in the code for this function.
401   The operand is a CODE_LABEL found in the insn chain.  */
402DEF_RTL_EXPR(LABEL_REF, "label_ref", "u", RTX_CONST_OBJ)
403
404/* Reference to a named label:
405   Operand 0: label name
406   Operand 1: flags (see SYMBOL_FLAG_* in rtl.h)
407   Operand 2: tree from which this symbol is derived, or null.
408   This is either a DECL node, or some kind of constant.  */
409DEF_RTL_EXPR(SYMBOL_REF, "symbol_ref", "s00", RTX_CONST_OBJ)
410
411/* The condition code register is represented, in our imagination,
412   as a register holding a value that can be compared to zero.
413   In fact, the machine has already compared them and recorded the
414   results; but instructions that look at the condition code
415   pretend to be looking at the entire value and comparing it.  */
416DEF_RTL_EXPR(CC0, "cc0", "", RTX_OBJ)
417
418/* ----------------------------------------------------------------------
419   Expressions for operators in an rtl pattern
420   ---------------------------------------------------------------------- */
421
422/* if_then_else.  This is used in representing ordinary
423   conditional jump instructions.
424     Operand:
425     0:  condition
426     1:  then expr
427     2:  else expr */
428DEF_RTL_EXPR(IF_THEN_ELSE, "if_then_else", "eee", RTX_TERNARY)
429
430/* Comparison, produces a condition code result.  */
431DEF_RTL_EXPR(COMPARE, "compare", "ee", RTX_BIN_ARITH)
432
433/* plus */
434DEF_RTL_EXPR(PLUS, "plus", "ee", RTX_COMM_ARITH)
435
436/* Operand 0 minus operand 1.  */
437DEF_RTL_EXPR(MINUS, "minus", "ee", RTX_BIN_ARITH)
438
439/* Minus operand 0.  */
440DEF_RTL_EXPR(NEG, "neg", "e", RTX_UNARY)
441
442DEF_RTL_EXPR(MULT, "mult", "ee", RTX_COMM_ARITH)
443
444/* Operand 0 divided by operand 1.  */
445DEF_RTL_EXPR(DIV, "div", "ee", RTX_BIN_ARITH)
446/* Remainder of operand 0 divided by operand 1.  */
447DEF_RTL_EXPR(MOD, "mod", "ee", RTX_BIN_ARITH)
448
449/* Unsigned divide and remainder.  */
450DEF_RTL_EXPR(UDIV, "udiv", "ee", RTX_BIN_ARITH)
451DEF_RTL_EXPR(UMOD, "umod", "ee", RTX_BIN_ARITH)
452
453/* Bitwise operations.  */
454DEF_RTL_EXPR(AND, "and", "ee", RTX_COMM_ARITH)
455DEF_RTL_EXPR(IOR, "ior", "ee", RTX_COMM_ARITH)
456DEF_RTL_EXPR(XOR, "xor", "ee", RTX_COMM_ARITH)
457DEF_RTL_EXPR(NOT, "not", "e", RTX_UNARY)
458
459/* Operand:
460     0:  value to be shifted.
461     1:  number of bits.  */
462DEF_RTL_EXPR(ASHIFT, "ashift", "ee", RTX_BIN_ARITH) /* shift left */
463DEF_RTL_EXPR(ROTATE, "rotate", "ee", RTX_BIN_ARITH) /* rotate left */
464DEF_RTL_EXPR(ASHIFTRT, "ashiftrt", "ee", RTX_BIN_ARITH) /* arithmetic shift right */
465DEF_RTL_EXPR(LSHIFTRT, "lshiftrt", "ee", RTX_BIN_ARITH) /* logical shift right */
466DEF_RTL_EXPR(ROTATERT, "rotatert", "ee", RTX_BIN_ARITH) /* rotate right */
467
468/* Minimum and maximum values of two operands.  We need both signed and
469   unsigned forms.  (We cannot use MIN for SMIN because it conflicts
470   with a macro of the same name.)   The signed variants should be used
471   with floating point.  Further, if both operands are zeros, or if either
472   operand is NaN, then it is unspecified which of the two operands is
473   returned as the result.  */
474
475DEF_RTL_EXPR(SMIN, "smin", "ee", RTX_COMM_ARITH)
476DEF_RTL_EXPR(SMAX, "smax", "ee", RTX_COMM_ARITH)
477DEF_RTL_EXPR(UMIN, "umin", "ee", RTX_COMM_ARITH)
478DEF_RTL_EXPR(UMAX, "umax", "ee", RTX_COMM_ARITH)
479
480/* These unary operations are used to represent incrementation
481   and decrementation as they occur in memory addresses.
482   The amount of increment or decrement are not represented
483   because they can be understood from the machine-mode of the
484   containing MEM.  These operations exist in only two cases:
485   1. pushes onto the stack.
486   2. created automatically by the life_analysis pass in flow.c.  */
487DEF_RTL_EXPR(PRE_DEC, "pre_dec", "e", RTX_AUTOINC)
488DEF_RTL_EXPR(PRE_INC, "pre_inc", "e", RTX_AUTOINC)
489DEF_RTL_EXPR(POST_DEC, "post_dec", "e", RTX_AUTOINC)
490DEF_RTL_EXPR(POST_INC, "post_inc", "e", RTX_AUTOINC)
491
492/* These binary operations are used to represent generic address
493   side-effects in memory addresses, except for simple incrementation
494   or decrementation which use the above operations.  They are
495   created automatically by the life_analysis pass in flow.c.
496   The first operand is a REG which is used as the address.
497   The second operand is an expression that is assigned to the
498   register, either before (PRE_MODIFY) or after (POST_MODIFY)
499   evaluating the address.
500   Currently, the compiler can only handle second operands of the
501   form (plus (reg) (reg)) and (plus (reg) (const_int)), where
502   the first operand of the PLUS has to be the same register as
503   the first operand of the *_MODIFY.  */
504DEF_RTL_EXPR(PRE_MODIFY, "pre_modify", "ee", RTX_AUTOINC)
505DEF_RTL_EXPR(POST_MODIFY, "post_modify", "ee", RTX_AUTOINC)
506
507/* Comparison operations.  The ordered comparisons exist in two
508   flavors, signed and unsigned.  */
509DEF_RTL_EXPR(NE, "ne", "ee", RTX_COMM_COMPARE)
510DEF_RTL_EXPR(EQ, "eq", "ee", RTX_COMM_COMPARE)
511DEF_RTL_EXPR(GE, "ge", "ee", RTX_COMPARE)
512DEF_RTL_EXPR(GT, "gt", "ee", RTX_COMPARE)
513DEF_RTL_EXPR(LE, "le", "ee", RTX_COMPARE)
514DEF_RTL_EXPR(LT, "lt", "ee", RTX_COMPARE)
515DEF_RTL_EXPR(GEU, "geu", "ee", RTX_COMPARE)
516DEF_RTL_EXPR(GTU, "gtu", "ee", RTX_COMPARE)
517DEF_RTL_EXPR(LEU, "leu", "ee", RTX_COMPARE)
518DEF_RTL_EXPR(LTU, "ltu", "ee", RTX_COMPARE)
519
520/* Additional floating point unordered comparison flavors.  */
521DEF_RTL_EXPR(UNORDERED, "unordered", "ee", RTX_COMM_COMPARE)
522DEF_RTL_EXPR(ORDERED, "ordered", "ee", RTX_COMM_COMPARE)
523
524/* These are equivalent to unordered or ...  */
525DEF_RTL_EXPR(UNEQ, "uneq", "ee", RTX_COMM_COMPARE)
526DEF_RTL_EXPR(UNGE, "unge", "ee", RTX_COMPARE)
527DEF_RTL_EXPR(UNGT, "ungt", "ee", RTX_COMPARE)
528DEF_RTL_EXPR(UNLE, "unle", "ee", RTX_COMPARE)
529DEF_RTL_EXPR(UNLT, "unlt", "ee", RTX_COMPARE)
530
531/* This is an ordered NE, ie !UNEQ, ie false for NaN.  */
532DEF_RTL_EXPR(LTGT, "ltgt", "ee", RTX_COMM_COMPARE)
533
534/* Represents the result of sign-extending the sole operand.
535   The machine modes of the operand and of the SIGN_EXTEND expression
536   determine how much sign-extension is going on.  */
537DEF_RTL_EXPR(SIGN_EXTEND, "sign_extend", "e", RTX_UNARY)
538
539/* Similar for zero-extension (such as unsigned short to int).  */
540DEF_RTL_EXPR(ZERO_EXTEND, "zero_extend", "e", RTX_UNARY)
541
542/* Similar but here the operand has a wider mode.  */
543DEF_RTL_EXPR(TRUNCATE, "truncate", "e", RTX_UNARY)
544
545/* Similar for extending floating-point values (such as SFmode to DFmode).  */
546DEF_RTL_EXPR(FLOAT_EXTEND, "float_extend", "e", RTX_UNARY)
547DEF_RTL_EXPR(FLOAT_TRUNCATE, "float_truncate", "e", RTX_UNARY)
548
549/* Conversion of fixed point operand to floating point value.  */
550DEF_RTL_EXPR(FLOAT, "float", "e", RTX_UNARY)
551
552/* With fixed-point machine mode:
553   Conversion of floating point operand to fixed point value.
554   Value is defined only when the operand's value is an integer.
555   With floating-point machine mode (and operand with same mode):
556   Operand is rounded toward zero to produce an integer value
557   represented in floating point.  */
558DEF_RTL_EXPR(FIX, "fix", "e", RTX_UNARY)
559
560/* Conversion of unsigned fixed point operand to floating point value.  */
561DEF_RTL_EXPR(UNSIGNED_FLOAT, "unsigned_float", "e", RTX_UNARY)
562
563/* With fixed-point machine mode:
564   Conversion of floating point operand to *unsigned* fixed point value.
565   Value is defined only when the operand's value is an integer.  */
566DEF_RTL_EXPR(UNSIGNED_FIX, "unsigned_fix", "e", RTX_UNARY)
567
568/* Absolute value */
569DEF_RTL_EXPR(ABS, "abs", "e", RTX_UNARY)
570
571/* Square root */
572DEF_RTL_EXPR(SQRT, "sqrt", "e", RTX_UNARY)
573
574/* Swap bytes.  */
575DEF_RTL_EXPR(BSWAP, "bswap", "e", RTX_UNARY)
576
577/* Find first bit that is set.
578   Value is 1 + number of trailing zeros in the arg.,
579   or 0 if arg is 0.  */
580DEF_RTL_EXPR(FFS, "ffs", "e", RTX_UNARY)
581
582/* Count leading zeros.  */
583DEF_RTL_EXPR(CLZ, "clz", "e", RTX_UNARY)
584
585/* Count trailing zeros.  */
586DEF_RTL_EXPR(CTZ, "ctz", "e", RTX_UNARY)
587
588/* Population count (number of 1 bits).  */
589DEF_RTL_EXPR(POPCOUNT, "popcount", "e", RTX_UNARY)
590
591/* Population parity (number of 1 bits modulo 2).  */
592DEF_RTL_EXPR(PARITY, "parity", "e", RTX_UNARY)
593
594/* Reference to a signed bit-field of specified size and position.
595   Operand 0 is the memory unit (usually SImode or QImode) which
596   contains the field's first bit.  Operand 1 is the width, in bits.
597   Operand 2 is the number of bits in the memory unit before the
598   first bit of this field.
599   If BITS_BIG_ENDIAN is defined, the first bit is the msb and
600   operand 2 counts from the msb of the memory unit.
601   Otherwise, the first bit is the lsb and operand 2 counts from
602   the lsb of the memory unit.
603   This kind of expression can not appear as an lvalue in RTL.  */
604DEF_RTL_EXPR(SIGN_EXTRACT, "sign_extract", "eee", RTX_BITFIELD_OPS)
605
606/* Similar for unsigned bit-field.
607   But note!  This kind of expression _can_ appear as an lvalue.  */
608DEF_RTL_EXPR(ZERO_EXTRACT, "zero_extract", "eee", RTX_BITFIELD_OPS)
609
610/* For RISC machines.  These save memory when splitting insns.  */
611
612/* HIGH are the high-order bits of a constant expression.  */
613DEF_RTL_EXPR(HIGH, "high", "e", RTX_CONST_OBJ)
614
615/* LO_SUM is the sum of a register and the low-order bits
616   of a constant expression.  */
617DEF_RTL_EXPR(LO_SUM, "lo_sum", "ee", RTX_OBJ)
618
619/* Describes a merge operation between two vector values.
620   Operands 0 and 1 are the vectors to be merged, operand 2 is a bitmask
621   that specifies where the parts of the result are taken from.  Set bits
622   indicate operand 0, clear bits indicate operand 1.  The parts are defined
623   by the mode of the vectors.  */
624DEF_RTL_EXPR(VEC_MERGE, "vec_merge", "eee", RTX_TERNARY)
625
626/* Describes an operation that selects parts of a vector.
627   Operands 0 is the source vector, operand 1 is a PARALLEL that contains
628   a CONST_INT for each of the subparts of the result vector, giving the
629   number of the source subpart that should be stored into it.  */
630DEF_RTL_EXPR(VEC_SELECT, "vec_select", "ee", RTX_BIN_ARITH)
631
632/* Describes a vector concat operation.  Operands 0 and 1 are the source
633   vectors, the result is a vector that is as long as operands 0 and 1
634   combined and is the concatenation of the two source vectors.  */
635DEF_RTL_EXPR(VEC_CONCAT, "vec_concat", "ee", RTX_BIN_ARITH)
636
637/* Describes an operation that converts a small vector into a larger one by
638   duplicating the input values.  The output vector mode must have the same
639   submodes as the input vector mode, and the number of output parts must be
640   an integer multiple of the number of input parts.  */
641DEF_RTL_EXPR(VEC_DUPLICATE, "vec_duplicate", "e", RTX_UNARY)
642
643/* Addition with signed saturation */
644DEF_RTL_EXPR(SS_PLUS, "ss_plus", "ee", RTX_COMM_ARITH)
645
646/* Addition with unsigned saturation */
647DEF_RTL_EXPR(US_PLUS, "us_plus", "ee", RTX_COMM_ARITH)
648
649/* Operand 0 minus operand 1, with signed saturation.  */
650DEF_RTL_EXPR(SS_MINUS, "ss_minus", "ee", RTX_BIN_ARITH)
651
652/* Negation with signed saturation.  */
653DEF_RTL_EXPR(SS_NEG, "ss_neg", "e", RTX_UNARY)
654
655/* Shift left with signed saturation.  */
656DEF_RTL_EXPR(SS_ASHIFT, "ss_ashift", "ee", RTX_BIN_ARITH)
657
658/* Operand 0 minus operand 1, with unsigned saturation.  */
659DEF_RTL_EXPR(US_MINUS, "us_minus", "ee", RTX_BIN_ARITH)
660
661/* Signed saturating truncate.  */
662DEF_RTL_EXPR(SS_TRUNCATE, "ss_truncate", "e", RTX_UNARY)
663
664/* Unsigned saturating truncate.  */
665DEF_RTL_EXPR(US_TRUNCATE, "us_truncate", "e", RTX_UNARY)
666
667/* Information about the variable and its location.  */
668DEF_RTL_EXPR(VAR_LOCATION, "var_location", "te", RTX_EXTRA)
669
670/* All expressions from this point forward appear only in machine
671   descriptions.  */
672#ifdef GENERATOR_FILE
673
674/* Include a secondary machine-description file at this point.  */
675DEF_RTL_EXPR(INCLUDE, "include", "s", RTX_EXTRA)
676
677/* Pattern-matching operators:  */
678
679/* Use the function named by the second arg (the string)
680   as a predicate; if matched, store the structure that was matched
681   in the operand table at index specified by the first arg (the integer).
682   If the second arg is the null string, the structure is just stored.
683
684   A third string argument indicates to the register allocator restrictions
685   on where the operand can be allocated.
686
687   If the target needs no restriction on any instruction this field should
688   be the null string.
689
690   The string is prepended by:
691   '=' to indicate the operand is only written to.
692   '+' to indicate the operand is both read and written to.
693
694   Each character in the string represents an allocable class for an operand.
695   'g' indicates the operand can be any valid class.
696   'i' indicates the operand can be immediate (in the instruction) data.
697   'r' indicates the operand can be in a register.
698   'm' indicates the operand can be in memory.
699   'o' a subset of the 'm' class.  Those memory addressing modes that
700       can be offset at compile time (have a constant added to them).
701
702   Other characters indicate target dependent operand classes and
703   are described in each target's machine description.
704
705   For instructions with more than one operand, sets of classes can be
706   separated by a comma to indicate the appropriate multi-operand constraints.
707   There must be a 1 to 1 correspondence between these sets of classes in
708   all operands for an instruction.
709   */
710DEF_RTL_EXPR(MATCH_OPERAND, "match_operand", "iss", RTX_MATCH)
711
712/* Match a SCRATCH or a register.  When used to generate rtl, a
713   SCRATCH is generated.  As for MATCH_OPERAND, the mode specifies
714   the desired mode and the first argument is the operand number.
715   The second argument is the constraint.  */
716DEF_RTL_EXPR(MATCH_SCRATCH, "match_scratch", "is", RTX_MATCH)
717
718/* Apply a predicate, AND match recursively the operands of the rtx.
719   Operand 0 is the operand-number, as in match_operand.
720   Operand 1 is a predicate to apply (as a string, a function name).
721   Operand 2 is a vector of expressions, each of which must match
722   one subexpression of the rtx this construct is matching.  */
723DEF_RTL_EXPR(MATCH_OPERATOR, "match_operator", "isE", RTX_MATCH)
724
725/* Match a PARALLEL of arbitrary length.  The predicate is applied
726   to the PARALLEL and the initial expressions in the PARALLEL are matched.
727   Operand 0 is the operand-number, as in match_operand.
728   Operand 1 is a predicate to apply to the PARALLEL.
729   Operand 2 is a vector of expressions, each of which must match the
730   corresponding element in the PARALLEL.  */
731DEF_RTL_EXPR(MATCH_PARALLEL, "match_parallel", "isE", RTX_MATCH)
732
733/* Match only something equal to what is stored in the operand table
734   at the index specified by the argument.  Use with MATCH_OPERAND.  */
735DEF_RTL_EXPR(MATCH_DUP, "match_dup", "i", RTX_MATCH)
736
737/* Match only something equal to what is stored in the operand table
738   at the index specified by the argument.  Use with MATCH_OPERATOR.  */
739DEF_RTL_EXPR(MATCH_OP_DUP, "match_op_dup", "iE", RTX_MATCH)
740
741/* Match only something equal to what is stored in the operand table
742   at the index specified by the argument.  Use with MATCH_PARALLEL.  */
743DEF_RTL_EXPR(MATCH_PAR_DUP, "match_par_dup", "iE", RTX_MATCH)
744
745/* Appears only in define_predicate/define_special_predicate
746   expressions.  Evaluates true only if the operand has an RTX code
747   from the set given by the argument (a comma-separated list).  If the
748   second argument is present and nonempty, it is a sequence of digits
749   and/or letters which indicates the subexpression to test, using the
750   same syntax as genextract/genrecog's location strings: 0-9 for
751   XEXP (op, n), a-z for XVECEXP (op, 0, n); each character applies to
752   the result of the one before it.  */
753DEF_RTL_EXPR(MATCH_CODE, "match_code", "ss", RTX_MATCH)
754
755/* Appears only in define_predicate/define_special_predicate
756    expressions.  The argument is a C expression to be injected at this
757    point in the predicate formula.  */
758DEF_RTL_EXPR(MATCH_TEST, "match_test", "s", RTX_MATCH)
759
760/* Insn (and related) definitions.  */
761
762/* Definition of the pattern for one kind of instruction.
763   Operand:
764   0: names this instruction.
765      If the name is the null string, the instruction is in the
766      machine description just to be recognized, and will never be emitted by
767      the tree to rtl expander.
768   1: is the pattern.
769   2: is a string which is a C expression
770      giving an additional condition for recognizing this pattern.
771      A null string means no extra condition.
772   3: is the action to execute if this pattern is matched.
773      If this assembler code template starts with a * then it is a fragment of
774      C code to run to decide on a template to use.  Otherwise, it is the
775      template to use.
776   4: optionally, a vector of attributes for this insn.
777     */
778DEF_RTL_EXPR(DEFINE_INSN, "define_insn", "sEsTV", RTX_EXTRA)
779
780/* Definition of a peephole optimization.
781   1st operand: vector of insn patterns to match
782   2nd operand: C expression that must be true
783   3rd operand: template or C code to produce assembler output.
784   4: optionally, a vector of attributes for this insn.
785
786   This form is deprecated; use define_peephole2 instead.  */
787DEF_RTL_EXPR(DEFINE_PEEPHOLE, "define_peephole", "EsTV", RTX_EXTRA)
788
789/* Definition of a split operation.
790   1st operand: insn pattern to match
791   2nd operand: C expression that must be true
792   3rd operand: vector of insn patterns to place into a SEQUENCE
793   4th operand: optionally, some C code to execute before generating the
794	insns.  This might, for example, create some RTX's and store them in
795	elements of `recog_data.operand' for use by the vector of
796	insn-patterns.
797	(`operands' is an alias here for `recog_data.operand').  */
798DEF_RTL_EXPR(DEFINE_SPLIT, "define_split", "EsES", RTX_EXTRA)
799
800/* Definition of an insn and associated split.
801   This is the concatenation, with a few modifications, of a define_insn
802   and a define_split which share the same pattern.
803   Operand:
804   0: names this instruction.
805      If the name is the null string, the instruction is in the
806      machine description just to be recognized, and will never be emitted by
807      the tree to rtl expander.
808   1: is the pattern.
809   2: is a string which is a C expression
810      giving an additional condition for recognizing this pattern.
811      A null string means no extra condition.
812   3: is the action to execute if this pattern is matched.
813      If this assembler code template starts with a * then it is a fragment of
814      C code to run to decide on a template to use.  Otherwise, it is the
815      template to use.
816   4: C expression that must be true for split.  This may start with "&&"
817      in which case the split condition is the logical and of the insn
818      condition and what follows the "&&" of this operand.
819   5: vector of insn patterns to place into a SEQUENCE
820   6: optionally, some C code to execute before generating the
821	insns.  This might, for example, create some RTX's and store them in
822	elements of `recog_data.operand' for use by the vector of
823	insn-patterns.
824	(`operands' is an alias here for `recog_data.operand').
825   7: optionally, a vector of attributes for this insn.  */
826DEF_RTL_EXPR(DEFINE_INSN_AND_SPLIT, "define_insn_and_split", "sEsTsESV", RTX_EXTRA)
827
828/* Definition of an RTL peephole operation.
829   Follows the same arguments as define_split.  */
830DEF_RTL_EXPR(DEFINE_PEEPHOLE2, "define_peephole2", "EsES", RTX_EXTRA)
831
832/* Define how to generate multiple insns for a standard insn name.
833   1st operand: the insn name.
834   2nd operand: vector of insn-patterns.
835	Use match_operand to substitute an element of `recog_data.operand'.
836   3rd operand: C expression that must be true for this to be available.
837	This may not test any operands.
838   4th operand: Extra C code to execute before generating the insns.
839	This might, for example, create some RTX's and store them in
840	elements of `recog_data.operand' for use by the vector of
841	insn-patterns.
842	(`operands' is an alias here for `recog_data.operand').  */
843DEF_RTL_EXPR(DEFINE_EXPAND, "define_expand", "sEss", RTX_EXTRA)
844
845/* Define a requirement for delay slots.
846   1st operand: Condition involving insn attributes that, if true,
847	        indicates that the insn requires the number of delay slots
848		shown.
849   2nd operand: Vector whose length is the three times the number of delay
850		slots required.
851	        Each entry gives three conditions, each involving attributes.
852		The first must be true for an insn to occupy that delay slot
853		location.  The second is true for all insns that can be
854		annulled if the branch is true and the third is true for all
855		insns that can be annulled if the branch is false.
856
857   Multiple DEFINE_DELAYs may be present.  They indicate differing
858   requirements for delay slots.  */
859DEF_RTL_EXPR(DEFINE_DELAY, "define_delay", "eE", RTX_EXTRA)
860
861/* Define attribute computation for `asm' instructions.  */
862DEF_RTL_EXPR(DEFINE_ASM_ATTRIBUTES, "define_asm_attributes", "V", RTX_EXTRA)
863
864/* Definition of a conditional execution meta operation.  Automatically
865   generates new instances of DEFINE_INSN, selected by having attribute
866   "predicable" true.  The new pattern will contain a COND_EXEC and the
867   predicate at top-level.
868
869   Operand:
870   0: The predicate pattern.  The top-level form should match a
871      relational operator.  Operands should have only one alternative.
872   1: A C expression giving an additional condition for recognizing
873      the generated pattern.
874   2: A template or C code to produce assembler output.  */
875DEF_RTL_EXPR(DEFINE_COND_EXEC, "define_cond_exec", "Ess", RTX_EXTRA)
876
877/* Definition of an operand predicate.  The difference between
878   DEFINE_PREDICATE and DEFINE_SPECIAL_PREDICATE is that genrecog will
879   not warn about a match_operand with no mode if it has a predicate
880   defined with DEFINE_SPECIAL_PREDICATE.
881
882   Operand:
883   0: The name of the predicate.
884   1: A boolean expression which computes whether or not the predicate
885      matches.  This expression can use IOR, AND, NOT, MATCH_OPERAND,
886      MATCH_CODE, and MATCH_TEST.  It must be specific enough that genrecog
887      can calculate the set of RTX codes that can possibly match.
888   2: A C function body which must return true for the predicate to match.
889      Optional.  Use this when the test is too complicated to fit into a
890      match_test expression.  */
891DEF_RTL_EXPR(DEFINE_PREDICATE, "define_predicate", "ses", RTX_EXTRA)
892DEF_RTL_EXPR(DEFINE_SPECIAL_PREDICATE, "define_special_predicate", "ses", RTX_EXTRA)
893
894/* Definition of a register operand constraint.  This simply maps the
895   constraint string to a register class.
896
897   Operand:
898   0: The name of the constraint (often, but not always, a single letter).
899   1: A C expression which evaluates to the appropriate register class for
900      this constraint.  If this is not just a constant, it should look only
901      at -m switches and the like.
902   2: A docstring for this constraint, in Texinfo syntax; not currently
903      used, in future will be incorporated into the manual's list of
904      machine-specific operand constraints.  */
905DEF_RTL_EXPR(DEFINE_REGISTER_CONSTRAINT, "define_register_constraint", "sss", RTX_EXTRA)
906
907/* Definition of a non-register operand constraint.  These look at the
908   operand and decide whether it fits the constraint.
909
910   DEFINE_CONSTRAINT gets no special treatment if it fails to match.
911   It is appropriate for constant-only constraints, and most others.
912
913   DEFINE_MEMORY_CONSTRAINT tells reload that this constraint can be made
914   to match, if it doesn't already, by converting the operand to the form
915   (mem (reg X)) where X is a base register.  It is suitable for constraints
916   that describe a subset of all memory references.
917
918   DEFINE_ADDRESS_CONSTRAINT tells reload that this constraint can be made
919   to match, if it doesn't already, by converting the operand to the form
920   (reg X) where X is a base register.  It is suitable for constraints that
921   describe a subset of all address references.
922
923   When in doubt, use plain DEFINE_CONSTRAINT.
924
925   Operand:
926   0: The name of the constraint (often, but not always, a single letter).
927   1: A docstring for this constraint, in Texinfo syntax; not currently
928      used, in future will be incorporated into the manual's list of
929      machine-specific operand constraints.
930   2: A boolean expression which computes whether or not the constraint
931      matches.  It should follow the same rules as a define_predicate
932      expression, including the bit about specifying the set of RTX codes
933      that could possibly match.  MATCH_TEST subexpressions may make use of
934      these variables:
935        `op'    - the RTL object defining the operand.
936        `mode'  - the mode of `op'.
937	`ival'  - INTVAL(op), if op is a CONST_INT.
938        `hval'  - CONST_DOUBLE_HIGH(op), if op is an integer CONST_DOUBLE.
939        `lval'  - CONST_DOUBLE_LOW(op), if op is an integer CONST_DOUBLE.
940        `rval'  - CONST_DOUBLE_REAL_VALUE(op), if op is a floating-point
941                  CONST_DOUBLE.
942      Do not use ival/hval/lval/rval if op is not the appropriate kind of
943      RTL object.  */
944DEF_RTL_EXPR(DEFINE_CONSTRAINT, "define_constraint", "sse", RTX_EXTRA)
945DEF_RTL_EXPR(DEFINE_MEMORY_CONSTRAINT, "define_memory_constraint", "sse", RTX_EXTRA)
946DEF_RTL_EXPR(DEFINE_ADDRESS_CONSTRAINT, "define_address_constraint", "sse", RTX_EXTRA)
947
948
949/* Constructions for CPU pipeline description described by NDFAs.  */
950
951/* (define_cpu_unit string [string]) describes cpu functional
952   units (separated by comma).
953
954   1st operand: Names of cpu functional units.
955   2nd operand: Name of automaton (see comments for DEFINE_AUTOMATON).
956
957   All define_reservations, define_cpu_units, and
958   define_query_cpu_units should have unique names which may not be
959   "nothing".  */
960DEF_RTL_EXPR(DEFINE_CPU_UNIT, "define_cpu_unit", "sS", RTX_EXTRA)
961
962/* (define_query_cpu_unit string [string]) describes cpu functional
963   units analogously to define_cpu_unit.  The reservation of such
964   units can be queried for automaton state.  */
965DEF_RTL_EXPR(DEFINE_QUERY_CPU_UNIT, "define_query_cpu_unit", "sS", RTX_EXTRA)
966
967/* (exclusion_set string string) means that each CPU functional unit
968   in the first string can not be reserved simultaneously with any
969   unit whose name is in the second string and vise versa.  CPU units
970   in the string are separated by commas.  For example, it is useful
971   for description CPU with fully pipelined floating point functional
972   unit which can execute simultaneously only single floating point
973   insns or only double floating point insns.  All CPU functional
974   units in a set should belong to the same automaton.  */
975DEF_RTL_EXPR(EXCLUSION_SET, "exclusion_set", "ss", RTX_EXTRA)
976
977/* (presence_set string string) means that each CPU functional unit in
978   the first string can not be reserved unless at least one of pattern
979   of units whose names are in the second string is reserved.  This is
980   an asymmetric relation.  CPU units or unit patterns in the strings
981   are separated by commas.  Pattern is one unit name or unit names
982   separated by white-spaces.
983
984   For example, it is useful for description that slot1 is reserved
985   after slot0 reservation for a VLIW processor.  We could describe it
986   by the following construction
987
988      (presence_set "slot1" "slot0")
989
990   Or slot1 is reserved only after slot0 and unit b0 reservation.  In
991   this case we could write
992
993      (presence_set "slot1" "slot0 b0")
994
995   All CPU functional units in a set should belong to the same
996   automaton.  */
997DEF_RTL_EXPR(PRESENCE_SET, "presence_set", "ss", RTX_EXTRA)
998
999/* (final_presence_set string string) is analogous to `presence_set'.
1000   The difference between them is when checking is done.  When an
1001   instruction is issued in given automaton state reflecting all
1002   current and planned unit reservations, the automaton state is
1003   changed.  The first state is a source state, the second one is a
1004   result state.  Checking for `presence_set' is done on the source
1005   state reservation, checking for `final_presence_set' is done on the
1006   result reservation.  This construction is useful to describe a
1007   reservation which is actually two subsequent reservations.  For
1008   example, if we use
1009
1010      (presence_set "slot1" "slot0")
1011
1012   the following insn will be never issued (because slot1 requires
1013   slot0 which is absent in the source state).
1014
1015      (define_reservation "insn_and_nop" "slot0 + slot1")
1016
1017   but it can be issued if we use analogous `final_presence_set'.  */
1018DEF_RTL_EXPR(FINAL_PRESENCE_SET, "final_presence_set", "ss", RTX_EXTRA)
1019
1020/* (absence_set string string) means that each CPU functional unit in
1021   the first string can be reserved only if each pattern of units
1022   whose names are in the second string is not reserved.  This is an
1023   asymmetric relation (actually exclusion set is analogous to this
1024   one but it is symmetric).  CPU units or unit patterns in the string
1025   are separated by commas.  Pattern is one unit name or unit names
1026   separated by white-spaces.
1027
1028   For example, it is useful for description that slot0 can not be
1029   reserved after slot1 or slot2 reservation for a VLIW processor.  We
1030   could describe it by the following construction
1031
1032      (absence_set "slot2" "slot0, slot1")
1033
1034   Or slot2 can not be reserved if slot0 and unit b0 are reserved or
1035   slot1 and unit b1 are reserved .  In this case we could write
1036
1037      (absence_set "slot2" "slot0 b0, slot1 b1")
1038
1039   All CPU functional units in a set should to belong the same
1040   automaton.  */
1041DEF_RTL_EXPR(ABSENCE_SET, "absence_set", "ss", RTX_EXTRA)
1042
1043/* (final_absence_set string string) is analogous to `absence_set' but
1044   checking is done on the result (state) reservation.  See comments
1045   for `final_presence_set'.  */
1046DEF_RTL_EXPR(FINAL_ABSENCE_SET, "final_absence_set", "ss", RTX_EXTRA)
1047
1048/* (define_bypass number out_insn_names in_insn_names) names bypass
1049   with given latency (the first number) from insns given by the first
1050   string (see define_insn_reservation) into insns given by the second
1051   string.  Insn names in the strings are separated by commas.  The
1052   third operand is optional name of function which is additional
1053   guard for the bypass.  The function will get the two insns as
1054   parameters.  If the function returns zero the bypass will be
1055   ignored for this case.  Additional guard is necessary to recognize
1056   complicated bypasses, e.g. when consumer is load address.  */
1057DEF_RTL_EXPR(DEFINE_BYPASS, "define_bypass", "issS", RTX_EXTRA)
1058
1059/* (define_automaton string) describes names of automata generated and
1060   used for pipeline hazards recognition.  The names are separated by
1061   comma.  Actually it is possibly to generate the single automaton
1062   but unfortunately it can be very large.  If we use more one
1063   automata, the summary size of the automata usually is less than the
1064   single one.  The automaton name is used in define_cpu_unit and
1065   define_query_cpu_unit.  All automata should have unique names.  */
1066DEF_RTL_EXPR(DEFINE_AUTOMATON, "define_automaton", "s", RTX_EXTRA)
1067
1068/* (automata_option string) describes option for generation of
1069   automata.  Currently there are the following options:
1070
1071   o "no-minimization" which makes no minimization of automata.  This
1072     is only worth to do when we are debugging the description and
1073     need to look more accurately at reservations of states.
1074
1075   o "time" which means printing additional time statistics about
1076      generation of automata.
1077
1078   o "v" which means generation of file describing the result
1079     automata.  The file has suffix `.dfa' and can be used for the
1080     description verification and debugging.
1081
1082   o "w" which means generation of warning instead of error for
1083     non-critical errors.
1084
1085   o "ndfa" which makes nondeterministic finite state automata.
1086
1087   o "progress" which means output of a progress bar showing how many
1088     states were generated so far for automaton being processed.  */
1089DEF_RTL_EXPR(AUTOMATA_OPTION, "automata_option", "s", RTX_EXTRA)
1090
1091/* (define_reservation string string) names reservation (the first
1092   string) of cpu functional units (the 2nd string).  Sometimes unit
1093   reservations for different insns contain common parts.  In such
1094   case, you can describe common part and use its name (the 1st
1095   parameter) in regular expression in define_insn_reservation.  All
1096   define_reservations, define_cpu_units, and define_query_cpu_units
1097   should have unique names which may not be "nothing".  */
1098DEF_RTL_EXPR(DEFINE_RESERVATION, "define_reservation", "ss", RTX_EXTRA)
1099
1100/* (define_insn_reservation name default_latency condition regexpr)
1101   describes reservation of cpu functional units (the 3nd operand) for
1102   instruction which is selected by the condition (the 2nd parameter).
1103   The first parameter is used for output of debugging information.
1104   The reservations are described by a regular expression according
1105   the following syntax:
1106
1107       regexp = regexp "," oneof
1108              | oneof
1109
1110       oneof = oneof "|" allof
1111             | allof
1112
1113       allof = allof "+" repeat
1114             | repeat
1115
1116       repeat = element "*" number
1117              | element
1118
1119       element = cpu_function_unit_name
1120               | reservation_name
1121               | result_name
1122               | "nothing"
1123               | "(" regexp ")"
1124
1125       1. "," is used for describing start of the next cycle in
1126       reservation.
1127
1128       2. "|" is used for describing the reservation described by the
1129       first regular expression *or* the reservation described by the
1130       second regular expression *or* etc.
1131
1132       3. "+" is used for describing the reservation described by the
1133       first regular expression *and* the reservation described by the
1134       second regular expression *and* etc.
1135
1136       4. "*" is used for convenience and simply means sequence in
1137       which the regular expression are repeated NUMBER times with
1138       cycle advancing (see ",").
1139
1140       5. cpu functional unit name which means its reservation.
1141
1142       6. reservation name -- see define_reservation.
1143
1144       7. string "nothing" means no units reservation.  */
1145
1146DEF_RTL_EXPR(DEFINE_INSN_RESERVATION, "define_insn_reservation", "sies", RTX_EXTRA)
1147
1148/* Expressions used for insn attributes.  */
1149
1150/* Definition of an insn attribute.
1151   1st operand: name of the attribute
1152   2nd operand: comma-separated list of possible attribute values
1153   3rd operand: expression for the default value of the attribute.  */
1154DEF_RTL_EXPR(DEFINE_ATTR, "define_attr", "sse", RTX_EXTRA)
1155
1156/* Marker for the name of an attribute.  */
1157DEF_RTL_EXPR(ATTR, "attr", "s", RTX_EXTRA)
1158
1159/* For use in the last (optional) operand of DEFINE_INSN or DEFINE_PEEPHOLE and
1160   in DEFINE_ASM_INSN to specify an attribute to assign to insns matching that
1161   pattern.
1162
1163   (set_attr "name" "value") is equivalent to
1164   (set (attr "name") (const_string "value"))  */
1165DEF_RTL_EXPR(SET_ATTR, "set_attr", "ss", RTX_EXTRA)
1166
1167/* In the last operand of DEFINE_INSN and DEFINE_PEEPHOLE, this can be used to
1168   specify that attribute values are to be assigned according to the
1169   alternative matched.
1170
1171   The following three expressions are equivalent:
1172
1173   (set (attr "att") (cond [(eq_attrq "alternative" "1") (const_string "a1")
1174			    (eq_attrq "alternative" "2") (const_string "a2")]
1175			   (const_string "a3")))
1176   (set_attr_alternative "att" [(const_string "a1") (const_string "a2")
1177				 (const_string "a3")])
1178   (set_attr "att" "a1,a2,a3")
1179 */
1180DEF_RTL_EXPR(SET_ATTR_ALTERNATIVE, "set_attr_alternative", "sE", RTX_EXTRA)
1181
1182/* A conditional expression true if the value of the specified attribute of
1183   the current insn equals the specified value.  The first operand is the
1184   attribute name and the second is the comparison value.  */
1185DEF_RTL_EXPR(EQ_ATTR, "eq_attr", "ss", RTX_EXTRA)
1186
1187/* A special case of the above representing a set of alternatives.  The first
1188   operand is bitmap of the set, the second one is the default value.  */
1189DEF_RTL_EXPR(EQ_ATTR_ALT, "eq_attr_alt", "ii", RTX_EXTRA)
1190
1191/* A conditional expression which is true if the specified flag is
1192   true for the insn being scheduled in reorg.
1193
1194   genattr.c defines the following flags which can be tested by
1195   (attr_flag "foo") expressions in eligible_for_delay.
1196
1197   forward, backward, very_likely, likely, very_unlikely, and unlikely.  */
1198
1199DEF_RTL_EXPR (ATTR_FLAG, "attr_flag", "s", RTX_EXTRA)
1200
1201/* General conditional. The first operand is a vector composed of pairs of
1202   expressions.  The first element of each pair is evaluated, in turn.
1203   The value of the conditional is the second expression of the first pair
1204   whose first expression evaluates nonzero.  If none of the expressions is
1205   true, the second operand will be used as the value of the conditional.  */
1206DEF_RTL_EXPR(COND, "cond", "Ee", RTX_EXTRA)
1207
1208#endif /* GENERATOR_FILE */
1209
1210/*
1211Local variables:
1212mode:c
1213End:
1214*/
1215