gcc/reg-notes.def - gcc - Git at Google

 /* 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
 version.

 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
 WARRANTY; without even the implied warranty of MERCHANTABILITY or
 FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 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
 <http://www.gnu.org/licenses/>.  */

 /* 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.  */
 #define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME)

 /* 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.  */
 REG_NOTE (DEP_TRUE)

 /* 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.  */
 REG_NOTE (DEAD)

 /* The REG is autoincremented or autodecremented in this insn.  */
 REG_NOTE (INC)

 /* 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.  */
 REG_NOTE (EQUIV)

 /* 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.  */
 REG_NOTE (EQUAL)

 /* 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.  */
 REG_NOTE (NONNEG)

 /* Identifies a register set in this insn and never used.  */
 REG_NOTE (UNUSED)

 /* 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.  */
 REG_NOTE (CC_SETTER)
 REG_NOTE (CC_USER)

 /* 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.  */
 REG_NOTE (LABEL_TARGET)

 /* 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_NOTE (LABEL_OPERAND)

 /* 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_NOTE (DEP_OUTPUT)
 REG_NOTE (DEP_ANTI)

 /* 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_NOTE (BR_PROB)

 /* 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.  */
 REG_NOTE (VALUE_PROFILE)

 /* Attached to a call insn; indicates that the call is malloc-like and
    that the pointer returned cannot alias anything else.  */
 REG_NOTE (NOALIAS)

 /* 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.  */
 REG_NOTE (BR_PRED)

 /* 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.  */
 REG_NOTE (FRAME_RELATED_EXPR)

 /* 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.  */
 REG_NOTE (EH_CONTEXT)

 /* 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.  */
 REG_NOTE (EH_REGION)

 /* Used by haifa-sched to save NOTE_INSN notes across scheduling.  */
 REG_NOTE (SAVE_NOTE)

 /* Indicates that a call does not return.  */
 REG_NOTE (NORETURN)

 /* Indicates that an indirect jump is a non-local goto instead of a
    computed goto.  */
 REG_NOTE (NON_LOCAL_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.  */
 REG_NOTE (CROSSING_JUMP)

 /* This kind of note is generated at each to `setjmp', and similar
    functions that can return twice.  */
 REG_NOTE (SETJMP)
	/* 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
	version.

	GCC is distributed in the hope that it will be useful, but WITHOUT ANY
	WARRANTY; without even the implied warranty of MERCHANTABILITY or
	FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
	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
	<http://www.gnu.org/licenses/>. */

	/* 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. */
	#define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME)

	/* 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. */
	REG_NOTE (DEP_TRUE)

	/* 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. */
	REG_NOTE (DEAD)

	/* The REG is autoincremented or autodecremented in this insn. */
	REG_NOTE (INC)

	/* 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. */
	REG_NOTE (EQUIV)

	/* 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. */
	REG_NOTE (EQUAL)

	/* 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. */
	REG_NOTE (NONNEG)

	/* Identifies a register set in this insn and never used. */
	REG_NOTE (UNUSED)

	/* 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. */
	REG_NOTE (CC_SETTER)
	REG_NOTE (CC_USER)

	/* 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. */
	REG_NOTE (LABEL_TARGET)

	/* 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_NOTE (LABEL_OPERAND)

	/* 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_NOTE (DEP_OUTPUT)
	REG_NOTE (DEP_ANTI)

	/* 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_NOTE (BR_PROB)

	/* 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. */
	REG_NOTE (VALUE_PROFILE)

	/* Attached to a call insn; indicates that the call is malloc-like and
	that the pointer returned cannot alias anything else. */
	REG_NOTE (NOALIAS)

	/* 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. */
	REG_NOTE (BR_PRED)

	/* 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. */
	REG_NOTE (FRAME_RELATED_EXPR)

	/* 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. */
	REG_NOTE (EH_CONTEXT)

	/* 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. */
	REG_NOTE (EH_REGION)

	/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */
	REG_NOTE (SAVE_NOTE)

	/* Indicates that a call does not return. */
	REG_NOTE (NORETURN)

	/* Indicates that an indirect jump is a non-local goto instead of a
	computed goto. */
	REG_NOTE (NON_LOCAL_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. */
	REG_NOTE (CROSSING_JUMP)

	/* This kind of note is generated at each to `setjmp', and similar
	functions that can return twice. */
	REG_NOTE (SETJMP)