1169689Skan/* Register note definitions. 2169689Skan Copyright (C) 2004, 2005 Free Software Foundation, Inc. 3169689Skan 4169689SkanThis file is part of GCC. 5169689Skan 6169689SkanGCC is free software; you can redistribute it and/or modify it under 7169689Skanthe terms of the GNU General Public License as published by the Free 8169689SkanSoftware Foundation; either version 2, or (at your option) any later 9169689Skanversion. 10169689Skan 11169689SkanGCC is distributed in the hope that it will be useful, but WITHOUT ANY 12169689SkanWARRANTY; without even the implied warranty of MERCHANTABILITY or 13169689SkanFITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 14169689Skanfor more details. 15169689Skan 16169689SkanYou should have received a copy of the GNU General Public License 17169689Skanalong with GCC; see the file COPYING. If not, write to the Free 18169689SkanSoftware Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 19169689Skan02110-1301, USA. */ 20169689Skan 21169689Skan/* This file defines all the codes that may appear on individual 22169689Skan EXPR_LIST rtxes in the REG_NOTES chain of an insn. The codes are 23169689Skan stored in the mode field of the EXPR_LIST. Source files define 24169689Skan DEF_REG_NOTE appropriately before including this file. */ 25169689Skan 26169689Skan/* Shorthand. */ 27169689Skan#define REG_NOTE(NAME) DEF_REG_NOTE (REG_##NAME) 28169689Skan 29169689Skan/* REG_DEP_TRUE is used in LOG_LINKS to represent a read-after-write 30169689Skan dependency (i.e. a true data dependency). This is here, not 31169689Skan grouped with REG_DEP_ANTI and REG_DEP_OUTPUT, because some passes 32169689Skan use a literal 0 for it. */ 33169689SkanREG_NOTE (DEP_TRUE) 34169689Skan 35169689Skan/* The value in REG dies in this insn (i.e., it is not needed past 36169689Skan this insn). If REG is set in this insn, the REG_DEAD note may, 37169689Skan but need not, be omitted. */ 38169689SkanREG_NOTE (DEAD) 39169689Skan 40169689Skan/* The REG is autoincremented or autodecremented in this insn. */ 41169689SkanREG_NOTE (INC) 42169689Skan 43169689Skan/* Describes the insn as a whole; it says that the insn sets a 44169689Skan register to a constant value or to be equivalent to a memory 45169689Skan address. If the register is spilled to the stack then the constant 46169689Skan value should be substituted for it. The contents of the REG_EQUIV 47169689Skan is the constant value or memory address, which may be different 48169689Skan from the source of the SET although it has the same value. A 49169689Skan REG_EQUIV note may also appear on an insn which copies a register 50169689Skan parameter to a pseudo-register, if there is a memory address which 51169689Skan could be used to hold that pseudo-register throughout the function. */ 52169689SkanREG_NOTE (EQUIV) 53169689Skan 54169689Skan/* Like REG_EQUIV except that the destination is only momentarily 55169689Skan equal to the specified rtx. Therefore, it cannot be used for 56169689Skan substitution; but it can be used for cse. */ 57169689SkanREG_NOTE (EQUAL) 58169689Skan 59169689Skan/* This insn copies the return-value of a library call out of the hard 60169689Skan reg for return values. This note is actually an INSN_LIST and it 61169689Skan points to the first insn involved in setting up arguments for the 62169689Skan call. flow.c uses this to delete the entire library call when its 63169689Skan result is dead. */ 64169689SkanREG_NOTE (RETVAL) 65169689Skan 66169689Skan/* The inverse of REG_RETVAL: it goes on the first insn of the library 67169689Skan call and points at the one that has the REG_RETVAL. This note is 68169689Skan also an INSN_LIST. */ 69169689SkanREG_NOTE (LIBCALL) 70169689Skan 71169689Skan/* The register is always nonnegative during the containing loop. 72169689Skan This is used in branches so that decrement and branch instructions 73169689Skan terminating on zero can be matched. There must be an insn pattern 74169689Skan in the md file named `decrement_and_branch_until_zero' or else this 75169689Skan will never be added to any instructions. */ 76169689SkanREG_NOTE (NONNEG) 77169689Skan 78169689Skan/* There is no conflict *after this insn* between the register in the 79169689Skan note and the destination of this insn. */ 80169689SkanREG_NOTE (NO_CONFLICT) 81169689Skan 82169689Skan/* Identifies a register set in this insn and never used. */ 83169689SkanREG_NOTE (UNUSED) 84169689Skan 85169689Skan/* REG_CC_SETTER and REG_CC_USER link a pair of insns that set and use 86169689Skan CC0, respectively. Normally, these are required to be consecutive 87169689Skan insns, but we permit putting a cc0-setting insn in the delay slot 88169689Skan of a branch as long as only one copy of the insn exists. In that 89169689Skan case, these notes point from one to the other to allow code 90169689Skan generation to determine what any require information and to 91169689Skan properly update CC_STATUS. These notes are INSN_LISTs. */ 92169689SkanREG_NOTE (CC_SETTER) 93169689SkanREG_NOTE (CC_USER) 94169689Skan 95169689Skan/* Points to a CODE_LABEL. Used by non-JUMP_INSNs to say that the 96169689Skan CODE_LABEL contained in the REG_LABEL note is used by the insn. 97169689Skan This note is an INSN_LIST. */ 98169689SkanREG_NOTE (LABEL) 99169689Skan 100169689Skan/* REG_DEP_ANTI and REG_DEP_OUTPUT are used in LOG_LINKS to represent 101169689Skan write-after-read and write-after-write dependencies respectively. */ 102169689SkanREG_NOTE (DEP_OUTPUT) 103169689SkanREG_NOTE (DEP_ANTI) 104169689Skan 105169689Skan/* REG_BR_PROB is attached to JUMP_INSNs and CALL_INSNs. It has an 106169689Skan integer value. For jumps, it is the probability that this is a 107169689Skan taken branch. For calls, it is the probability that this call 108169689Skan won't return. */ 109169689SkanREG_NOTE (BR_PROB) 110169689Skan 111169689Skan/* REG_VALUE_PROFILE is attached when the profile is read in to an 112169689Skan insn before that the code to profile the value is inserted. It 113169689Skan contains the results of profiling. */ 114169689SkanREG_NOTE (VALUE_PROFILE) 115169689Skan 116169689Skan/* Attached to a call insn; indicates that the call is malloc-like and 117169689Skan that the pointer returned cannot alias anything else. */ 118169689SkanREG_NOTE (NOALIAS) 119169689Skan 120169689Skan/* REG_BR_PRED is attached to JUMP_INSNs and CALL_INSNSs. It contains 121169689Skan CONCAT of two integer value. First specifies the branch predictor 122169689Skan that added the note, second specifies the predicted hitrate of 123169689Skan branch in the same format as REG_BR_PROB note uses. */ 124169689SkanREG_NOTE (BR_PRED) 125169689Skan 126169689Skan/* Attached to insns that are RTX_FRAME_RELATED_P, but are too complex 127169689Skan for DWARF to interpret what they imply. The attached rtx is used 128169689Skan instead of intuition. */ 129169689SkanREG_NOTE (FRAME_RELATED_EXPR) 130169689Skan 131169689Skan/* Indicates that REG holds the exception context for the function. 132169689Skan This context is shared by inline functions, so the code to acquire 133169689Skan the real exception context is delayed until after inlining. */ 134169689SkanREG_NOTE (EH_CONTEXT) 135169689Skan 136169689Skan/* Indicates what exception region an INSN belongs in. This is used 137169689Skan to indicate what region to which a call may throw. REGION 0 138169689Skan indicates that a call cannot throw at all. REGION -1 indicates 139169689Skan that it cannot throw, nor will it execute a non-local goto. */ 140169689SkanREG_NOTE (EH_REGION) 141169689Skan 142169689Skan/* Used by haifa-sched to save NOTE_INSN notes across scheduling. */ 143169689SkanREG_NOTE (SAVE_NOTE) 144169689Skan 145169689Skan/* Indicates that this insn (which is part of the prologue) computes a 146169689Skan value which might not be used later, and if so it's OK to delete 147169689Skan the insn. Normally, deleting any insn in the prologue is an error. 148169689Skan At present the parameter is unused and set to (const_int 0). */ 149169689SkanREG_NOTE (MAYBE_DEAD) 150169689Skan 151169689Skan/* Indicates that a call does not return. */ 152169689SkanREG_NOTE (NORETURN) 153169689Skan 154169689Skan/* Indicates that an indirect jump is a non-local goto instead of a 155169689Skan computed goto. */ 156169689SkanREG_NOTE (NON_LOCAL_GOTO) 157169689Skan 158169689Skan/* Indicates that a jump crosses between hot and cold sections in a 159169689Skan (partitioned) assembly or .o file, and therefore should not be 160169689Skan reduced to a simpler jump by optimizations. */ 161169689SkanREG_NOTE (CROSSING_JUMP) 162169689Skan 163169689Skan/* This kind of note is generated at each to `setjmp', and similar 164169689Skan functions that can return twice. */ 165169689SkanREG_NOTE (SETJMP) 166