ira.c use DF infrastructure for combine_and_move_insns
[official-gcc.git] / gcc / reg-notes.def
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1 /* Register note definitions.
2 Copyright (C) 2004-2016 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it under
7 the terms of the GNU General Public License as published by the Free
8 Software Foundation; either version 3, or (at your option) any later
9 version.
11 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
12 WARRANTY; without even the implied warranty of MERCHANTABILITY or
13 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING3. If not see
18 <http://www.gnu.org/licenses/>. */
20 /* This file defines all the codes that may appear on individual
21 EXPR_LIST, INSN_LIST and INT_LIST rtxes in the REG_NOTES chain of an insn.
22 The codes are stored in the mode field of the rtx. Source files
23 define DEF_REG_NOTE appropriately before including this file. */
25 /* Shorthand. */
26 #define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME)
28 /* REG_DEP_TRUE is used in scheduler dependencies lists to represent a
29 read-after-write dependency (i.e. a true data dependency). This is
30 here, not grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some
31 passes use a literal 0 for it. */
32 REG_NOTE (DEP_TRUE)
34 /* The value in REG dies in this insn (i.e., it is not needed past
35 this insn). If REG is set in this insn, the REG_DEAD note may,
36 but need not, be omitted. */
37 REG_NOTE (DEAD)
39 /* The REG is autoincremented or autodecremented in this insn. */
40 REG_NOTE (INC)
42 /* Describes the insn as a whole; it says that the insn sets a
43 register to a constant value or to be equivalent to a memory
44 address. If the register is spilled to the stack then the constant
45 value should be substituted for it. The contents of the REG_EQUIV
46 is the constant value or memory address, which may be different
47 from the source of the SET although it has the same value. A
48 REG_EQUIV note may also appear on an insn which copies a register
49 parameter to a pseudo-register, if there is a memory address which
50 could be used to hold that pseudo-register throughout the function. */
51 REG_NOTE (EQUIV)
53 /* Like REG_EQUIV except that the destination is only momentarily
54 equal to the specified rtx. Therefore, it cannot be used for
55 substitution; but it can be used for cse. */
56 REG_NOTE (EQUAL)
58 /* The register is always nonnegative during the containing loop.
59 This is used in branches so that decrement and branch instructions
60 terminating on zero can be matched. There must be an insn pattern
61 in the md file named `decrement_and_branch_until_zero' or else this
62 will never be added to any instructions. */
63 REG_NOTE (NONNEG)
65 /* Identifies a register set in this insn and never used. */
66 REG_NOTE (UNUSED)
68 /* REG_CC_SETTER and REG_CC_USER link a pair of insns that set and use
69 CC0, respectively. Normally, these are required to be consecutive
70 insns, but we permit putting a cc0-setting insn in the delay slot
71 of a branch as long as only one copy of the insn exists. In that
72 case, these notes point from one to the other to allow code
73 generation to determine what any require information and to
74 properly update CC_STATUS. These notes are INSN_LISTs. */
75 REG_NOTE (CC_SETTER)
76 REG_NOTE (CC_USER)
78 /* Points to a CODE_LABEL. Used by JUMP_INSNs to say that the CODE_LABEL
79 contained in the REG_LABEL_TARGET note is a possible jump target of
80 this insn. This note is an INSN_LIST. */
81 REG_NOTE (LABEL_TARGET)
83 /* Points to a CODE_LABEL. Used by any insn to say that the CODE_LABEL
84 contained in the REG_LABEL_OPERAND note is used by the insn, but as an
85 operand, not as a jump target (though it may indirectly be a jump
86 target for a later jump insn). This note is an INSN_LIST. */
87 REG_NOTE (LABEL_OPERAND)
89 /* REG_DEP_OUTPUT and REG_DEP_ANTI are used in scheduler dependencies lists
90 to represent write-after-write and write-after-read dependencies
91 respectively. */
92 REG_NOTE (DEP_OUTPUT)
93 REG_NOTE (DEP_ANTI)
94 REG_NOTE (DEP_CONTROL)
96 /* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an
97 integer value (in an INT_LIST). For jumps, it is the probability
98 that this is a taken branch. For calls, it is the probability that
99 this call won't return. */
100 REG_NOTE (BR_PROB)
102 /* Attached to a call insn; indicates that the call is malloc-like and
103 that the pointer returned cannot alias anything else. */
104 REG_NOTE (NOALIAS)
106 /* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains
107 CONCAT of two integer value. First specifies the branch predictor
108 that added the note, second specifies the predicted hitrate of
109 branch in the same format as REG_BR_PROB note uses. */
110 REG_NOTE (BR_PRED)
112 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
113 for DWARF to interpret what they imply. The attached rtx is used
114 instead of intuition. */
115 REG_NOTE (FRAME_RELATED_EXPR)
117 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
118 for FRAME_RELATED_EXPR intuition. The insn's first pattern must be
119 a SET, and the destination must be the CFA register. The attached
120 rtx is an expression that defines the CFA. In the simplest case, the
121 rtx could be just the stack_pointer_rtx; more common would be a PLUS
122 with a base register and a constant offset. In the most complicated
123 cases, this will result in a DW_CFA_def_cfa_expression with the rtx
124 expression rendered in a dwarf location expression. */
125 REG_NOTE (CFA_DEF_CFA)
127 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
128 for FRAME_RELATED_EXPR intuition. This note adjusts the expression
129 from which the CFA is computed. The attached rtx defines a new CFA
130 expression, relative to the old CFA expression. This rtx must be of
131 the form (SET new-cfa-reg (PLUS old-cfa-reg const_int)). If the note
132 rtx is NULL, we use the first SET of the insn. */
133 REG_NOTE (CFA_ADJUST_CFA)
135 /* Similar to FRAME_RELATED_EXPR, with the additional information that
136 this is a save to memory, i.e. will result in DW_CFA_offset or the
137 like. The pattern or the insn should be a simple store relative to
138 the CFA. */
139 REG_NOTE (CFA_OFFSET)
141 /* Similar to FRAME_RELATED_EXPR, with the additional information that this
142 is a save to a register, i.e. will result in DW_CFA_register. The insn
143 or the pattern should be simple reg-reg move. */
144 REG_NOTE (CFA_REGISTER)
146 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
147 for FRAME_RELATED_EXPR intuition. This is a save to memory, i.e. will
148 result in a DW_CFA_expression. The pattern or the insn should be a
149 store of a register to an arbitrary (non-validated) memory address. */
150 REG_NOTE (CFA_EXPRESSION)
152 /* Attached to insns that are RTX_FRAME_RELATED_P, with the information
153 that this is a restore operation, i.e. will result in DW_CFA_restore
154 or the like. Either the attached rtx, or the destination of the insn's
155 first pattern is the register to be restored. */
156 REG_NOTE (CFA_RESTORE)
158 /* Attached to insns that are RTX_FRAME_RELATED_P, marks insn that sets
159 vDRAP from DRAP. If vDRAP is a register, vdrap_reg is initalized
160 to the argument, if it is a MEM, it is ignored. */
161 REG_NOTE (CFA_SET_VDRAP)
163 /* Attached to insns that are RTX_FRAME_RELATED_P, indicating a window
164 save operation, i.e. will result in a DW_CFA_GNU_window_save.
165 The argument is ignored. */
166 REG_NOTE (CFA_WINDOW_SAVE)
168 /* Attached to insns that are RTX_FRAME_RELATED_P, marks the insn as
169 requiring that all queued information should be flushed *before* insn,
170 regardless of what is visible in the rtl. The argument is ignored.
171 This is normally used for a call instruction which is not exposed to
172 the rest of the compiler as a CALL_INSN. */
173 REG_NOTE (CFA_FLUSH_QUEUE)
175 /* Indicates what exception region an INSN belongs in. This is used
176 to indicate what region to which a call may throw. REGION 0
177 indicates that a call cannot throw at all. REGION -1 indicates
178 that it cannot throw, nor will it execute a non-local goto. */
179 REG_NOTE (EH_REGION)
181 /* Used by haifa-sched to save NOTE_INSN notes across scheduling. */
182 REG_NOTE (SAVE_NOTE)
184 /* Indicates that a call does not return. */
185 REG_NOTE (NORETURN)
187 /* Indicates that an indirect jump is a non-local goto instead of a
188 computed goto. */
189 REG_NOTE (NON_LOCAL_GOTO)
191 /* This kind of note is generated at each to `setjmp', and similar
192 functions that can return twice. */
193 REG_NOTE (SETJMP)
195 /* This kind of note is generated at each transactional memory
196 builtin, to indicate we need to generate transaction restart
197 edges for this insn. */
198 REG_NOTE (TM)
200 /* Indicates the cumulative offset of the stack pointer accounting
201 for pushed arguments. This will only be generated when
202 ACCUMULATE_OUTGOING_ARGS is false. */
203 REG_NOTE (ARGS_SIZE)
205 /* Used for communication between IRA and caller-save.c, indicates
206 that the return value of a call can be used to reinitialize a
207 pseudo reg. */
208 REG_NOTE (RETURNED)
210 /* Used to mark a call with the function decl called by the call.
211 The decl might not be available in the call due to splitting of the call
212 insn. This note is a SYMBOL_REF. */
213 REG_NOTE (CALL_DECL)