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/* Register note definitions.
Copyright (C) 2004, 2005, 2006, 2007, 2008 Free Software Foundation, Inc.
This file is part of GCC.
GCC is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free
Software Foundation; either version 3, or (at your option) any later
GCC is distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
for more details.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING3. If not see
<>. */
/* This file defines all the codes that may appear on individual
EXPR_LIST rtxes in the REG_NOTES chain of an insn. The codes are
stored in the mode field of the EXPR_LIST. Source files define
DEF_REG_NOTE appropriately before including this file. */
/* Shorthand. */
/* REG_DEP_TRUE is used in scheduler dependencies lists to represent a
read-after-write dependency (i.e. a true data dependency). This is
here, not grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some
passes use a literal 0 for it. */
/* The value in REG dies in this insn (i.e., it is not needed past
this insn). If REG is set in this insn, the REG_DEAD note may,
but need not, be omitted. */
/* The REG is autoincremented or autodecremented in this insn. */
/* Describes the insn as a whole; it says that the insn sets a
register to a constant value or to be equivalent to a memory
address. If the register is spilled to the stack then the constant
value should be substituted for it. The contents of the REG_EQUIV
is the constant value or memory address, which may be different
from the source of the SET although it has the same value. A
REG_EQUIV note may also appear on an insn which copies a register
parameter to a pseudo-register, if there is a memory address which
could be used to hold that pseudo-register throughout the function. */
/* Like REG_EQUIV except that the destination is only momentarily
equal to the specified rtx. Therefore, it cannot be used for
substitution; but it can be used for cse. */
/* The register is always nonnegative during the containing loop.
This is used in branches so that decrement and branch instructions
terminating on zero can be matched. There must be an insn pattern
in the md file named `decrement_and_branch_until_zero' or else this
will never be added to any instructions. */
/* Identifies a register set in this insn and never used. */
/* REG_CC_SETTER and REG_CC_USER link a pair of insns that set and use
CC0, respectively. Normally, these are required to be consecutive
insns, but we permit putting a cc0-setting insn in the delay slot
of a branch as long as only one copy of the insn exists. In that
case, these notes point from one to the other to allow code
generation to determine what any require information and to
properly update CC_STATUS. These notes are INSN_LISTs. */
/* Points to a CODE_LABEL. Used by JUMP_INSNs to say that the CODE_LABEL
contained in the REG_LABEL_TARGET note is a possible jump target of
this insn. This note is an INSN_LIST. */
/* Points to a CODE_LABEL. Used by any insn to say that the CODE_LABEL
contained in the REG_LABEL_OPERAND note is used by the insn, but as an
operand, not as a jump target (though it may indirectly be a jump
target for a later jump insn). This note is an INSN_LIST. */
/* REG_DEP_OUTPUT and REG_DEP_ANTI are used in scheduler dependencies lists
to represent write-after-write and write-after-read dependencies
respectively. */
/* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an
integer value. For jumps, it is the probability that this is a
taken branch. For calls, it is the probability that this call
won't return. */
/* REG_VALUE_PROFILE is attached when the profile is read in to an
insn before that the code to profile the value is inserted. It
contains the results of profiling. */
/* Attached to a call insn; indicates that the call is malloc-like and
that the pointer returned cannot alias anything else. */
/* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains
CONCAT of two integer value. First specifies the branch predictor
that added the note, second specifies the predicted hitrate of
branch in the same format as REG_BR_PROB note uses. */
/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex
for DWARF to interpret what they imply. The attached rtx is used
instead of intuition. */
/* Indicates that REG holds the exception context for the function.
This context is shared by inline functions, so the code to acquire
the real exception context is delayed until after inlining. */
/* Indicates what exception region an INSN belongs in. This is used
to indicate what region to which a call may throw. REGION 0
indicates that a call cannot throw at all. REGION -1 indicates
that it cannot throw, nor will it execute a non-local goto. */
/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */
/* Indicates that a call does not return. */
/* Indicates that an indirect jump is a non-local goto instead of a
computed goto. */
/* Indicates that a jump crosses between hot and cold sections in a
(partitioned) assembly or .o file, and therefore should not be
reduced to a simpler jump by optimizations. */
/* This kind of note is generated at each to `setjmp', and similar
functions that can return twice. */