1/* Register note definitions. 2 Copyright (C) 2004, 2005 Free Software Foundation, Inc. 3 4This file is part of GCC. 5 6GCC is free software; you can redistribute it and/or modify it under 7the terms of the GNU General Public License as published by the Free 8Software Foundation; either version 2, or (at your option) any later 9version. 10 11GCC is distributed in the hope that it will be useful, but WITHOUT ANY 12WARRANTY; without even the implied warranty of MERCHANTABILITY or 13FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14for more details. 15 16You should have received a copy of the GNU General Public License 17along with GCC; see the file COPYING. If not, write to the Free 18Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 1902110-1301, USA. */ 20 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. */ 25 26/* Shorthand. */ 27#define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME) 28 29/* REG_DEP_TRUE is used in LOG_LINKS to represent a read-after-write 30 dependency (i.e. a true data dependency). This is here, not 31 grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some passes 32 use a literal 0 for it. */ 33REG_NOTE (DEP_TRUE) 34 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. */ 38REG_NOTE (DEAD) 39 40/* The REG is autoincremented or autodecremented in this insn. */ 41REG_NOTE (INC) 42 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. */ 52REG_NOTE (EQUIV) 53 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. */ 57REG_NOTE (EQUAL) 58 59/* This insn copies the return-value of a library call out of the hard 60 reg for return values. This note is actually an INSN_LIST and it 61 points to the first insn involved in setting up arguments for the 62 call. flow.c uses this to delete the entire library call when its 63 result is dead. */ 64REG_NOTE (RETVAL) 65 66/* The inverse of REG_RETVAL: it goes on the first insn of the library 67 call and points at the one that has the REG_RETVAL. This note is 68 also an INSN_LIST. */ 69REG_NOTE (LIBCALL) 70 71/* The register is always nonnegative during the containing loop. 72 This is used in branches so that decrement and branch instructions 73 terminating on zero can be matched. There must be an insn pattern 74 in the md file named `decrement_and_branch_until_zero' or else this 75 will never be added to any instructions. */ 76REG_NOTE (NONNEG) 77 78/* There is no conflict *after this insn* between the register in the 79 note and the destination of this insn. */ 80REG_NOTE (NO_CONFLICT) 81 82/* Identifies a register set in this insn and never used. */ 83REG_NOTE (UNUSED) 84 85/* REG_CC_SETTER and REG_CC_USER link a pair of insns that set and use 86 CC0, respectively. Normally, these are required to be consecutive 87 insns, but we permit putting a cc0-setting insn in the delay slot 88 of a branch as long as only one copy of the insn exists. In that 89 case, these notes point from one to the other to allow code 90 generation to determine what any require information and to 91 properly update CC_STATUS. These notes are INSN_LISTs. */ 92REG_NOTE (CC_SETTER) 93REG_NOTE (CC_USER) 94 95/* Points to a CODE_LABEL. Used by non-JUMP_INSNs to say that the 96 CODE_LABEL contained in the REG_LABEL note is used by the insn. 97 This note is an INSN_LIST. */ 98REG_NOTE (LABEL) 99 100/* REG_DEP_ANTI and REG_DEP_OUTPUT are used in LOG_LINKS to represent 101 write-after-read and write-after-write dependencies respectively. */ 102REG_NOTE (DEP_OUTPUT) 103REG_NOTE (DEP_ANTI) 104 105/* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an 106 integer value. For jumps, it is the probability that this is a 107 taken branch. For calls, it is the probability that this call 108 won't return. */ 109REG_NOTE (BR_PROB) 110 111/* REG_VALUE_PROFILE is attached when the profile is read in to an 112 insn before that the code to profile the value is inserted. It 113 contains the results of profiling. */ 114REG_NOTE (VALUE_PROFILE) 115 116/* Attached to a call insn; indicates that the call is malloc-like and 117 that the pointer returned cannot alias anything else. */ 118REG_NOTE (NOALIAS) 119 120/* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains 121 CONCAT of two integer value. First specifies the branch predictor 122 that added the note, second specifies the predicted hitrate of 123 branch in the same format as REG_BR_PROB note uses. */ 124REG_NOTE (BR_PRED) 125 126/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 127 for DWARF to interpret what they imply. The attached rtx is used 128 instead of intuition. */ 129REG_NOTE (FRAME_RELATED_EXPR) 130 131/* Indicates that REG holds the exception context for the function. 132 This context is shared by inline functions, so the code to acquire 133 the real exception context is delayed until after inlining. */ 134REG_NOTE (EH_CONTEXT) 135 136/* Indicates what exception region an INSN belongs in. This is used 137 to indicate what region to which a call may throw. REGION 0 138 indicates that a call cannot throw at all. REGION -1 indicates 139 that it cannot throw, nor will it execute a non-local goto. */ 140REG_NOTE (EH_REGION) 141 142/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */ 143REG_NOTE (SAVE_NOTE) 144 145/* Indicates that this insn (which is part of the prologue) computes a 146 value which might not be used later, and if so it's OK to delete 147 the insn. Normally, deleting any insn in the prologue is an error. 148 At present the parameter is unused and set to (const_int 0). */ 149REG_NOTE (MAYBE_DEAD) 150 151/* Indicates that a call does not return. */ 152REG_NOTE (NORETURN) 153 154/* Indicates that an indirect jump is a non-local goto instead of a 155 computed goto. */ 156REG_NOTE (NON_LOCAL_GOTO) 157 158/* Indicates that a jump crosses between hot and cold sections in a 159 (partitioned) assembly or .o file, and therefore should not be 160 reduced to a simpler jump by optimizations. */ 161REG_NOTE (CROSSING_JUMP) 162 163/* This kind of note is generated at each to `setjmp', and similar 164 functions that can return twice. */ 165REG_NOTE (SETJMP) 166