* config/rs6000/rs6000.c (rs6000_option_override_internal): Do not
[official-gcc.git] / gcc / reg-notes.def
blob640abb217d5ff44a9f6c6fe754c134cd738328fb
1 /* Register note definitions.
2 Copyright (C) 2004, 2005, 2006, 2007, 2008, 2009, 2010
3 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 3, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING3. If not see
19 <http://www.gnu.org/licenses/>. */
21 /* This file defines all the codes that may appear on individual
22 EXPR_LIST rtxes in the REG_NOTES chain of an insn. The codes are
23 stored in the mode field of the EXPR_LIST. Source files define
24 DEF_REG_NOTE appropriately before including this file. */
26 /* Shorthand. */
27 #define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME)
29 /* REG_DEP_TRUE is used in scheduler dependencies lists to represent a
30 read-after-write dependency (i.e. a true data dependency). This is
31 here, not grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some
32 passes use a literal 0 for it. */
33 REG_NOTE (DEP_TRUE)
35 /* The value in REG dies in this insn (i.e., it is not needed past
36 this insn). If REG is set in this insn, the REG_DEAD note may,
37 but need not, be omitted. */
38 REG_NOTE (DEAD)
40 /* The REG is autoincremented or autodecremented in this insn. */
41 REG_NOTE (INC)
43 /* Describes the insn as a whole; it says that the insn sets a
44 register to a constant value or to be equivalent to a memory
45 address. If the register is spilled to the stack then the constant
46 value should be substituted for it. The contents of the REG_EQUIV
47 is the constant value or memory address, which may be different
48 from the source of the SET although it has the same value. A
49 REG_EQUIV note may also appear on an insn which copies a register
50 parameter to a pseudo-register, if there is a memory address which
51 could be used to hold that pseudo-register throughout the function. */
52 REG_NOTE (EQUIV)
54 /* Like REG_EQUIV except that the destination is only momentarily
55 equal to the specified rtx. Therefore, it cannot be used for
56 substitution; but it can be used for cse. */
57 REG_NOTE (EQUAL)
59 /* The register is always nonnegative during the containing loop.
60 This is used in branches so that decrement and branch instructions
61 terminating on zero can be matched. There must be an insn pattern
62 in the md file named `decrement_and_branch_until_zero' or else this
63 will never be added to any instructions. */
64 REG_NOTE (NONNEG)
66 /* Identifies a register set in this insn and never used. */
67 REG_NOTE (UNUSED)
69 /* REG_CC_SETTER and REG_CC_USER link a pair of insns that set and use
70 CC0, respectively. Normally, these are required to be consecutive
71 insns, but we permit putting a cc0-setting insn in the delay slot
72 of a branch as long as only one copy of the insn exists. In that
73 case, these notes point from one to the other to allow code
74 generation to determine what any require information and to
75 properly update CC_STATUS. These notes are INSN_LISTs. */
76 REG_NOTE (CC_SETTER)
77 REG_NOTE (CC_USER)
79 /* Points to a CODE_LABEL. Used by JUMP_INSNs to say that the CODE_LABEL
80 contained in the REG_LABEL_TARGET note is a possible jump target of
81 this insn. This note is an INSN_LIST. */
82 REG_NOTE (LABEL_TARGET)
84 /* Points to a CODE_LABEL. Used by any insn to say that the CODE_LABEL
85 contained in the REG_LABEL_OPERAND note is used by the insn, but as an
86 operand, not as a jump target (though it may indirectly be a jump
87 target for a later jump insn). This note is an INSN_LIST. */
88 REG_NOTE (LABEL_OPERAND)
90 /* REG_DEP_OUTPUT and REG_DEP_ANTI are used in scheduler dependencies lists
91 to represent write-after-write and write-after-read dependencies
92 respectively. */
93 REG_NOTE (DEP_OUTPUT)
94 REG_NOTE (DEP_ANTI)
95 REG_NOTE (DEP_CONTROL)
97 /* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an
98 integer value. For jumps, it is the probability that this is a
99 taken branch. For calls, it is the probability that this call
100 won't return. */
101 REG_NOTE (BR_PROB)
103 /* Attached to a call insn; indicates that the call is malloc-like and
104 that the pointer returned cannot alias anything else. */
105 REG_NOTE (NOALIAS)
107 /* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains
108 CONCAT of two integer value. First specifies the branch predictor
109 that added the note, second specifies the predicted hitrate of
110 branch in the same format as REG_BR_PROB note uses. */
111 REG_NOTE (BR_PRED)
113 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
114 for DWARF to interpret what they imply. The attached rtx is used
115 instead of intuition. */
116 REG_NOTE (FRAME_RELATED_EXPR)
118 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
119 for FRAME_RELATED_EXPR intuition. The insn's first pattern must be
120 a SET, and the destination must be the CFA register. The attached
121 rtx is an expression that defines the CFA. In the simplest case, the
122 rtx could be just the stack_pointer_rtx; more common would be a PLUS
123 with a base register and a constant offset. In the most complicated
124 cases, this will result in a DW_CFA_def_cfa_expression with the rtx
125 expression rendered in a dwarf location expression. */
126 REG_NOTE (CFA_DEF_CFA)
128 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
129 for FRAME_RELATED_EXPR intuition. This note adjusts the expression
130 from which the CFA is computed. The attached rtx defines a new CFA
131 expression, relative to the old CFA expression. This rtx must be of
132 the form (SET new-cfa-reg (PLUS old-cfa-reg const_int)). If the note
133 rtx is NULL, we use the first SET of the insn. */
134 REG_NOTE (CFA_ADJUST_CFA)
136 /* Similar to FRAME_RELATED_EXPR, with the additional information that
137 this is a save to memory, i.e. will result in DW_CFA_offset or the
138 like. The pattern or the insn should be a simple store relative to
139 the CFA. */
140 REG_NOTE (CFA_OFFSET)
142 /* Similar to FRAME_RELATED_EXPR, with the additional information that this
143 is a save to a register, i.e. will result in DW_CFA_register. The insn
144 or the pattern should be simple reg-reg move. */
145 REG_NOTE (CFA_REGISTER)
147 /* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
148 for FRAME_RELATED_EXPR intuition. This is a save to memory, i.e. will
149 result in a DW_CFA_expression. The pattern or the insn should be a
150 store of a register to an arbitrary (non-validated) memory address. */
151 REG_NOTE (CFA_EXPRESSION)
153 /* Attached to insns that are RTX_FRAME_RELATED_P, with the information
154 that this is a restore operation, i.e. will result in DW_CFA_restore
155 or the like. Either the attached rtx, or the destination of the insn's
156 first pattern is the register to be restored. */
157 REG_NOTE (CFA_RESTORE)
159 /* Attached to insns that are RTX_FRAME_RELATED_P, marks insn that sets
160 vDRAP from DRAP. If vDRAP is a register, vdrap_reg is initalized
161 to the argument, if it is a MEM, it is ignored. */
162 REG_NOTE (CFA_SET_VDRAP)
164 /* Attached to insns that are RTX_FRAME_RELATED_P, indicating a window
165 save operation, i.e. will result in a DW_CFA_GNU_window_save.
166 The argument is ignored. */
167 REG_NOTE (CFA_WINDOW_SAVE)
169 /* Attached to insns that are RTX_FRAME_RELATED_P, marks the insn as
170 requiring that all queued information should be flushed *before* insn,
171 regardless of what is visible in the rtl. The argument is ignored.
172 This is normally used for a call instruction which is not exposed to
173 the rest of the compiler as a CALL_INSN. */
174 REG_NOTE (CFA_FLUSH_QUEUE)
176 /* Indicates that REG holds the exception context for the function.
177 This context is shared by inline functions, so the code to acquire
178 the real exception context is delayed until after inlining. */
179 REG_NOTE (EH_CONTEXT)
181 /* Indicates what exception region an INSN belongs in. This is used
182 to indicate what region to which a call may throw. REGION 0
183 indicates that a call cannot throw at all. REGION -1 indicates
184 that it cannot throw, nor will it execute a non-local goto. */
185 REG_NOTE (EH_REGION)
187 /* Used by haifa-sched to save NOTE_INSN notes across scheduling. */
188 REG_NOTE (SAVE_NOTE)
190 /* Indicates that a call does not return. */
191 REG_NOTE (NORETURN)
193 /* Indicates that an indirect jump is a non-local goto instead of a
194 computed goto. */
195 REG_NOTE (NON_LOCAL_GOTO)
197 /* Indicates that a jump crosses between hot and cold sections in a
198 (partitioned) assembly or .o file, and therefore should not be
199 reduced to a simpler jump by optimizations. */
200 REG_NOTE (CROSSING_JUMP)
202 /* This kind of note is generated at each to `setjmp', and similar
203 functions that can return twice. */
204 REG_NOTE (SETJMP)
206 /* This kind of note is generated at each transactional memory
207 builtin, to indicate we need to generate transaction restart
208 edges for this insn. */
209 REG_NOTE (TM)
211 /* Indicates the cumulative offset of the stack pointer accounting
212 for pushed arguments. This will only be generated when
213 ACCUMULATE_OUTGOING_ARGS is false. */
214 REG_NOTE (ARGS_SIZE)
216 /* Used for communication between IRA and caller-save.c, indicates
217 that the return value of a call can be used to reinitialize a
218 pseudo reg. */
219 REG_NOTE (RETURNED)