diff options
Diffstat (limited to 'gcc')
| -rw-r--r-- | gcc/ChangeLog | 4 | ||||
| -rw-r--r-- | gcc/doc/rtl.texi | 532 |
2 files changed, 326 insertions, 210 deletions
diff --git a/gcc/ChangeLog b/gcc/ChangeLog index ddfc3e0..ffcac4c 100644 --- a/gcc/ChangeLog +++ b/gcc/ChangeLog @@ -1,3 +1,7 @@ +2002-01-07 Janis Johnson <janis187@us.ibm.com> + + * doc/rtl.texi (Flags): Clean up documentation of RTL flags + 2002-01-07 Marek Michalkiewicz <marekm@amelek.gda.pl> * config/avr/avr.c (avr_mcu_types): Add new MCU types. diff --git a/gcc/doc/rtl.texi b/gcc/doc/rtl.texi index a137b3d..93db82b 100644 --- a/gcc/doc/rtl.texi +++ b/gcc/doc/rtl.texi @@ -369,60 +369,175 @@ to access them. @section Flags in an RTL Expression @cindex flags in RTL expression -RTL expressions contain several flags (one-bit bit-fields) and other -values that are used in certain types of expression. Most often they -are accessed with the following macros: +RTL expressions contain several flags (one-bit bit-fields) +that are used in certain types of expression. Most often they +are accessed with the following macros, which expand into lvalues: @table @code -@findex MEM_VOLATILE_P -@cindex @code{mem} and @samp{/v} -@cindex @code{volatil}, in @code{mem} -@cindex @samp{/v} in RTL dump -@item MEM_VOLATILE_P (@var{x}) -In @code{mem} expressions, nonzero for volatile memory references. +@findex CONSTANT_POOL_ADDRESS_P +@cindex @code{symbol_ref} and @samp{/u} +@cindex @code{unchanging}, in @code{symbol_ref} +@item CONSTANT_POOL_ADDRESS_P (@var{x}) +Nonzero in a @code{symbol_ref} if it refers to part of the current +function's constant pool. For most targets these addresses are in a +@code{.rodata} section entirely separate from the function, but for +some targets the addresses are close to the beginning of the function. +In either case GCC assumes these addresses can be addressed directly, +perhaps with the help of base registers. +Stored in the @code{unchanging} field and printed as @samp{/u}. + +@findex CONST_OR_PURE_CALL_P +@cindex @code{call_insn} and @samp{/u} +@cindex @code{unchanging}, in @code{call_insn} +@item CONST_OR_PURE_CALL_P (@var{x}) +In a @code{call_insn}, @code{note}, or an @code{expr_list} for notes, +indicates that the insn represents a call to a const or pure function. +Stored in the @code{unchanging} field and printed as @samp{/u}. + +@findex INSN_ANNULLED_BRANCH_P +@cindex @code{insn} and @samp{/u} +@cindex @code{unchanging}, in @code{insn} +@item INSN_ANNULLED_BRANCH_P (@var{x}) +In an @code{insn} in the delay slot of a branch insn, indicates that an +annulling branch should be used. See the discussion under +@code{sequence} below. Stored in the @code{unchanging} field and printed +as @samp{/u}. + +@findex INSN_DEAD_CODE_P +@cindex @code{insn} and @samp{/s} +@cindex @code{in_struct}, in @code{insn} +@item INSN_DEAD_CODE_P (@var{x}) +In an @code{insn} during the dead-code elimination pass, nonzero if the +insn is dead. +Stored in the @code{in_struct} field and printed as @samp{/s}. + +@findex INSN_DELETED_P +@cindex @code{insn} and @samp{/v} +@cindex @code{volatil}, in @code{insn} +@item INSN_DELETED_P (@var{x}) +In an @code{insn}, nonzero if the insn has been deleted. Stored in the +@code{volatil} field and printed as @samp{/v}. + +@findex INSN_FROM_TARGET_P +@cindex @code{insn} and @samp{/s} +@cindex @code{in_struct}, in @code{insn} +@item INSN_FROM_TARGET_P (@var{x}) +In an @code{insn} in a delay slot of a branch, indicates that the insn +is from the target of the branch. If the branch insn has +@code{INSN_ANNULLED_BRANCH_P} set, this insn will only be executed if +the branch is taken. For annulled branches with +@code{INSN_FROM_TARGET_P} clear, the insn will be executed only if the +branch is not taken. When @code{INSN_ANNULLED_BRANCH_P} is not set, +this insn will always be executed. Stored in the @code{in_struct} +field and printed as @samp{/s}. + +@findex LABEL_OUTSIDE_LOOP_P +@cindex @code{label_ref} and @samp{/s} +@cindex @code{in_struct}, in @code{label_ref} +@item LABEL_OUTSIDE_LOOP_P (@var{x}) +In @code{label_ref} expressions, nonzero if this is a reference to a +label that is outside the innermost loop containing the reference to the +label. Stored in the @code{in_struct} field and printed as @samp{/s}. + +@findex LABEL_PRESERVE_P +@cindex @code{code_label} and @samp{/i} +@cindex @code{in_struct}, in @code{code_label} +@item LABEL_PRESERVE_P (@var{x}) +In a @code{code_label}, indicates that the label is referenced by +code or data not visible to the RTL of a given function. +Labels referenced by a non-local goto will have this bit set. Stored +in the @code{in_struct} field and printed as @samp{/s}. + +@findex LABEL_REF_NONLOCAL_P +@cindex @code{label_ref} and @samp{/v} +@cindex @code{volatil}, in @code{label_ref} +@item LABEL_REF_NONLOCAL_P (@var{x}) +In @code{label_ref} and @code{reg_label} expressions, nonzero if this is +a reference to a non-local label. Stored in the @code{volatil} field and printed as @samp{/v}. +@findex LINK_COST_FREE +@cindex @code{insn_list} and @samp{/c} +@cindex @code{call}, in @code{insn_list} +@item LINK_COST_FREE (@var{x}) +In the @code{LOG_LINKS} @code{insn_list} during scheduling, nonzero when +the cost of executing an instruction through the link is zero, i.e., the +link makes the cost free. Stored in the @code{call} field and printed +as @samp{/c}. + +@findex LINK_COST_ZERO +@cindex @code{insn_list} and @samp{/j} +@cindex @code{jump}, in @code{insn_list} +@item LINK_COST_ZERO (@var{x}) +In the @code{LOG_LINKS} @code{insn_list} during scheduling, nonzero when +the cost of executing an instruction through the link varies and is +unchanged, i.e., the link has zero additional cost. +Stored in the @code{jump} field and printed as @samp{/j}. + @findex MEM_IN_STRUCT_P @cindex @code{mem} and @samp{/s} @cindex @code{in_struct}, in @code{mem} -@cindex @samp{/s} in RTL dump @item MEM_IN_STRUCT_P (@var{x}) In @code{mem} expressions, nonzero for reference to an entire structure, union or array, or to a component of one. Zero for references to a -scalar variable or through a pointer to a scalar. Stored in the -@code{in_struct} field and printed as @samp{/s}. If both this flag and -MEM_SCALAR_P are clear, then we don't know whether this MEM is in a -structure or not. Both flags should never be simultaneously set. +scalar variable or through a pointer to a scalar. If both this flag and +@code{MEM_SCALAR_P} are clear, then we don't know whether this @code{mem} +is in a structure or not. Both flags should never be simultaneously set. +Stored in the @code{in_struct} field and printed as @samp{/s}. + +@findex MEM_KEEP_ALIAS_SET_P +@cindex @code{mem} and @samp{/j} +@cindex @code{jump}, in @code{mem} +@item MEM_KEEP_ALIAS_SET_P (@var{x}) +In @code{mem} expressions, 1 if we should keep the alias set for this +mem unchanged when we access a component. Set to 1, for example, when we +are already in a non-addressable component of an aggregate. +Stored in the @code{jump} field and printed as @samp{/j}. @findex MEM_SCALAR_P @cindex @code{mem} and @samp{/f} -@cindex @code{frame_related}, in@code{mem} -@cindex @samp{/f} in RTL dump +@cindex @code{frame_related}, in @code{mem} @item MEM_SCALAR_P (@var{x}) In @code{mem} expressions, nonzero for reference to a scalar known not to be a member of a structure, union, or array. Zero for such references and for indirections through pointers, even pointers pointing -to scalar types. If both this flag and MEM_STRUCT_P are clear, then we -don't know whether this MEM is in a structure or not. Both flags should +to scalar types. If both this flag and @code{MEM_STRUCT_P} are clear, then we +don't know whether this @code{mem} is in a structure or not. Both flags should never be simultaneously set. +Stored in the @code{frame_related} field and printed as @samp{/f}. -@findex MEM_ALIAS_SET -@item MEM_ALIAS_SET (@var{x}) -In @code{mem} expressions, the alias set to which @var{x} belongs. If -zero, @var{x} is not in any alias set, and may alias anything. If -nonzero, @var{x} may only alias objects in the same alias set. This -value is set (in a language-specific manner) by the front end. This -field is not a bit-field; it is in an integer, found as the second -argument to the @code{mem}. +@findex MEM_VOLATILE_P +@cindex @code{mem} and @samp{/v} +@cindex @code{volatil}, in @code{mem} +@item MEM_VOLATILE_P (@var{x}) +In @code{mem} and @code{asm_operands} expressions, nonzero for volatile +memory references. +Stored in the @code{volatil} field and printed as @samp{/v}. + +@findex REG_FUNCTION_VALUE_P +@cindex @code{reg} and @samp{/i} +@cindex @code{integrated}, in @code{reg} +@item REG_FUNCTION_VALUE_P (@var{x}) +Nonzero in a @code{reg} if it is the place in which this function's +value is going to be returned. (This happens only in a hard +register.) Stored in the @code{integrated} field and printed as +@samp{/i}. @findex REG_LOOP_TEST_P @cindex @code{reg} and @samp{/s} @cindex @code{in_struct}, in @code{reg} -@item REG_LOOP_TEST_P +@item REG_LOOP_TEST_P (@var{x}) In @code{reg} expressions, nonzero if this register's entire life is contained in the exit test code for some loop. Stored in the @code{in_struct} field and printed as @samp{/s}. +@findex REG_POINTER +@cindex @code{reg} and @samp{/f} +@cindex @code{frame_related}, in @code{reg} +@item REG_POINTER (@var{x}) +Nonzero in a @code{reg} if the register holds a pointer. Stored in the +@code{frame_related} field and printed as @samp{/f}. + @findex REG_USERVAR_P @cindex @code{reg} and @samp{/v} @cindex @code{volatil}, in @code{reg} @@ -432,75 +547,19 @@ the user's source code. Zero for temporaries generated internally by the compiler. Stored in the @code{volatil} field and printed as @samp{/v}. -@cindex @samp{/i} in RTL dump -@findex REG_FUNCTION_VALUE_P -@cindex @code{reg} and @samp{/i} -@cindex @code{integrated}, in @code{reg} -@item REG_FUNCTION_VALUE_P (@var{x}) -Nonzero in a @code{reg} if it is the place in which this function's -value is going to be returned. (This happens only in a hard -register.) Stored in the @code{integrated} field and printed as -@samp{/i}. - The same hard register may be used also for collecting the values of functions called by this one, but @code{REG_FUNCTION_VALUE_P} is zero in this kind of use. -@cindex @samp{/f} in RTL dump -@findex REG_POINTER -@cindex @code{reg} and @samp{/f} -@cindex @code{frame_related}, in @code{reg} -@item REG_POINTER (@var{x}) -Nonzero in a @code{reg} if the register holds a pointer. Stored in the -@code{frame_related} field and printed as @samp{/f}. - -@findex SUBREG_PROMOTED_VAR_P -@cindex @code{subreg} and @samp{/s} -@cindex @code{in_struct}, in @code{subreg} -@item SUBREG_PROMOTED_VAR_P -Nonzero in a @code{subreg} if it was made when accessing an object that -was promoted to a wider mode in accord with the @code{PROMOTED_MODE} machine -description macro (@pxref{Storage Layout}). In this case, the mode of -the @code{subreg} is the declared mode of the object and the mode of -@code{SUBREG_REG} is the mode of the register that holds the object. -Promoted variables are always either sign- or zero-extended to the wider -mode on every assignment. Stored in the @code{in_struct} field and -printed as @samp{/s}. - -@findex SUBREG_PROMOTED_UNSIGNED_P -@cindex @code{subreg} and @samp{/u} -@cindex @code{unchanging}, in @code{subreg} -@item SUBREG_PROMOTED_UNSIGNED_P -Nonzero in a @code{subreg} that has @code{SUBREG_PROMOTED_VAR_P} nonzero -if the object being referenced is kept zero-extended and zero if it -is kept sign-extended. Stored in the @code{unchanging} field and -printed as @samp{/u}. - -@findex RTX_UNCHANGING_P -@cindex @code{reg} and @samp{/u} -@cindex @code{mem} and @samp{/u} -@cindex @code{unchanging}, in @code{reg} and @code{mem} -@cindex @samp{/u} in RTL dump -@item RTX_UNCHANGING_P (@var{x}) -Nonzero in a @code{reg} or @code{mem} if the value is not changed. -(This flag is not set for memory references via pointers to constants. -Such pointers only guarantee that the object will not be changed -explicitly by the current function. The object might be changed by -other functions or by aliasing.) Stored in the -@code{unchanging} field and printed as @samp{/u}. - -@findex RTX_INTEGRATED_P -@cindex @code{integrated}, in @code{insn} -@item RTX_INTEGRATED_P (@var{insn}) -Nonzero in an insn if it resulted from an in-line function call. -Stored in the @code{integrated} field and printed as @samp{/i}. - @findex RTX_FRAME_RELATED_P +@cindex @code{insn} and @samp{/f} +@cindex @code{frame_related}, in @code{insn} @item RTX_FRAME_RELATED_P (@var{x}) -Nonzero in an insn or expression which is part of a function prologue +Nonzero in an @code{insn} or @code{set} which is part of a function prologue and sets the stack pointer, sets the frame pointer, or saves a register. This flag should also be set on an instruction that sets up a temporary register to use in place of the frame pointer. +Stored in the @code{frame_related} field and printed as @samp{/f}. In particular, on RISC targets where there are limits on the sizes of immediate constants, it is sometimes impossible to reach the register @@ -521,12 +580,77 @@ computation performed by this instruction, i.e., one that This flag is required for exception handling support on targets with RTL prologues. -@findex SYMBOL_REF_USED -@cindex @code{used}, in @code{symbol_ref} -@item SYMBOL_REF_USED (@var{x}) -In a @code{symbol_ref}, indicates that @var{x} has been used. This is -normally only used to ensure that @var{x} is only declared external -once. Stored in the @code{used} field. +@findex RTX_INTEGRATED_P +@cindex @code{insn} and @samp{/i} +@cindex @code{integrated}, in @code{insn} +@item RTX_INTEGRATED_P (@var{x}) +Nonzero in an @code{insn}, @code{insn_list}, or @code{const} if it +resulted from an in-line function call. +Stored in the @code{integrated} field and printed as @samp{/i}. + +@findex RTX_UNCHANGING_P +@cindex @code{reg} and @samp{/u} +@cindex @code{mem} and @samp{/u} +@cindex @code{unchanging}, in @code{reg} and @code{mem} +@item RTX_UNCHANGING_P (@var{x}) +Nonzero in a @code{reg} or @code{mem} if the memory is set at most once, +anywhere. This does not mean that it is function invariant. +Stored in the @code{unchanging} field and printed as @samp{/u}. + +@findex SCHED_GROUP_P +@cindex @code{insn} and @samp{/i} +@cindex @code{in_struct}, in @code{insn} +@item SCHED_GROUP_P (@var{x}) +During instruction scheduling, in an @code{insn}, indicates that the +previous insn must be scheduled together with this insn. This is used to +ensure that certain groups of instructions will not be split up by the +instruction scheduling pass, for example, @code{use} insns before +a @code{call_insn} may not be separated from the @code{call_insn}. +Stored in the @code{in_struct} field and printed as @samp{/s}. + +@findex SET_IS_RETURN_P +@cindex @code{insn} and @samp{/j} +@cindex @code{jump}, in @code{insn} +@item SET_IS_RETURN_P (@var{x}) +For a @code{set}, nonzero if it is for a return. +Stored in the @code{jump} field and printed as @samp{/j}. + +@findex SIBLING_CALL_P +@cindex @code{call_insn} and @samp{/j} +@cindex @code{jump}, in @code{call_insn} +@item SIBLING_CALL_P (@var{x}) +For a @code{call_insn}, nonzero if the insn is a sibling call. +Stored in the @code{jump} field and printed as @samp{/j}. + +@findex STRING_POOL_ADDRESS_P +@cindex @code{symbol_ref} and @samp{/f} +@cindex @code{frame_related}, in @code{symbol_ref} +@item STRING_POOL_ADDRESS_P (@var{x}) +For a @code{symbol_ref} expression, nonzero if it addresses this function's +string constant pool. +Stored in the @code{frame_related} field and printed as @samp{/f}. + +@findex SUBREG_PROMOTED_UNSIGNED_P +@cindex @code{subreg} and @samp{/u} +@cindex @code{unchanging}, in @code{subreg} +@item SUBREG_PROMOTED_UNSIGNED_P (@var{x}) +Nonzero in a @code{subreg} that has @code{SUBREG_PROMOTED_VAR_P} nonzero +if the object being referenced is kept zero-extended and zero if it +is kept sign-extended. Stored in the @code{unchanging} field and +printed as @samp{/u}. + +@findex SUBREG_PROMOTED_VAR_P +@cindex @code{subreg} and @samp{/s} +@cindex @code{in_struct}, in @code{subreg} +@item SUBREG_PROMOTED_VAR_P (@var{x}) +Nonzero in a @code{subreg} if it was made when accessing an object that +was promoted to a wider mode in accord with the @code{PROMOTED_MODE} machine +description macro (@pxref{Storage Layout}). In this case, the mode of +the @code{subreg} is the declared mode of the object and the mode of +@code{SUBREG_REG} is the mode of the register that holds the object. +Promoted variables are always either sign- or zero-extended to the wider +mode on every assignment. Stored in the @code{in_struct} field and +printed as @samp{/s}. @findex SYMBOL_REF_FLAG @cindex @code{symbol_ref} and @samp{/v} @@ -535,122 +659,51 @@ once. Stored in the @code{used} field. In a @code{symbol_ref}, this is used as a flag for machine-specific purposes. Stored in the @code{volatil} field and printed as @samp{/v}. +@findex SYMBOL_REF_USED +@cindex @code{used}, in @code{symbol_ref} +@item SYMBOL_REF_USED (@var{x}) +In a @code{symbol_ref}, indicates that @var{x} has been used. This is +normally only used to ensure that @var{x} is only declared external +once. Stored in the @code{used} field. + @findex SYMBOL_REF_WEAK @cindex @code{symbol_ref} and @samp{/i} @cindex @code{integrated}, in @code{symbol_ref} @item SYMBOL_REF_WEAK (@var{x}) In a @code{symbol_ref}, indicates that @var{x} has been declared weak. Stored in the @code{integrated} field and printed as @samp{/i}. - -@findex LABEL_OUTSIDE_LOOP_P -@cindex @code{label_ref} and @samp{/s} -@cindex @code{in_struct}, in @code{label_ref} -@item LABEL_OUTSIDE_LOOP_P -In @code{label_ref} expressions, nonzero if this is a reference to a -label that is outside the innermost loop containing the reference to the -label. Stored in the @code{in_struct} field and printed as @samp{/s}. - -@findex INSN_DELETED_P -@cindex @code{volatil}, in @code{insn} -@item INSN_DELETED_P (@var{insn}) -In an insn, nonzero if the insn has been deleted. Stored in the -@code{volatil} field and printed as @samp{/v}. - -@findex INSN_ANNULLED_BRANCH_P -@cindex @code{insn} and @samp{/u} -@cindex @code{unchanging}, in @code{insn} -@item INSN_ANNULLED_BRANCH_P (@var{insn}) -In an @code{insn} in the delay slot of a branch insn, indicates that an -annulling branch should be used. See the discussion under -@code{sequence} below. Stored in the @code{unchanging} field and printed -as @samp{/u}. - -@findex INSN_FROM_TARGET_P -@cindex @code{insn} and @samp{/s} -@cindex @code{in_struct}, in @code{insn} -@cindex @samp{/s} in RTL dump -@item INSN_FROM_TARGET_P (@var{insn}) -In an @code{insn} in a delay slot of a branch, indicates that the insn -is from the target of the branch. If the branch insn has -@code{INSN_ANNULLED_BRANCH_P} set, this insn will only be executed if -the branch is taken. For annulled branches with -@code{INSN_FROM_TARGET_P} clear, the insn will be executed only if the -branch is not taken. When @code{INSN_ANNULLED_BRANCH_P} is not set, -this insn will always be executed. Stored in the @code{in_struct} -field and printed as @samp{/s}. - -@findex CONSTANT_POOL_ADDRESS_P -@cindex @code{symbol_ref} and @samp{/u} -@cindex @code{unchanging}, in @code{symbol_ref} -@item CONSTANT_POOL_ADDRESS_P (@var{x}) -Nonzero in a @code{symbol_ref} if it refers to part of the current -function's ``constants pool''. These are addresses close to the -beginning of the function, and GCC assumes they can be addressed -directly (perhaps with the help of base registers). Stored in the -@code{unchanging} field and printed as @samp{/u}. - -@findex CONST_CALL_P -@cindex @code{call_insn} and @samp{/u} -@cindex @code{unchanging}, in @code{call_insn} -@item CONST_CALL_P (@var{x}) -In a @code{call_insn}, indicates that the insn represents a call to a const -function. Stored in the @code{unchanging} field and printed as @samp{/u}. - -@findex LABEL_PRESERVE_P -@cindex @code{code_label} and @samp{/i} -@cindex @code{in_struct}, in @code{code_label} -@item LABEL_PRESERVE_P (@var{x}) -In a @code{code_label}, indicates that the label can never be deleted. -Labels referenced by a non-local goto will have this bit set. Stored -in the @code{in_struct} field and printed as @samp{/s}. - -@findex SCHED_GROUP_P -@cindex @code{insn} and @samp{/i} -@cindex @code{in_struct}, in @code{insn} -@item SCHED_GROUP_P (@var{insn}) -During instruction scheduling, in an insn, indicates that the previous insn -must be scheduled together with this insn. This is used to ensure that -certain groups of instructions will not be split up by the instruction -scheduling pass, for example, @code{use} insns before a @code{call_insn} may -not be separated from the @code{call_insn}. Stored in the @code{in_struct} -field and printed as @samp{/s}. @end table -These are the fields which the above macros refer to: +These are the fields to which the above macros refer: @table @code -@findex used -@item used -Normally, this flag is used only momentarily, at the end of RTL -generation for a function, to count the number of times an expression -appears in insns. Expressions that appear more than once are copied, -according to the rules for shared structure (@pxref{Sharing}). +@findex call +@cindex @samp{/c} in RTL dump +@item call +In the @code{LOG_LINKS} of an @code{insn_list} during scheduling, 1 means that +the cost of executing an instruction through the link is zero. -In a @code{symbol_ref}, it indicates that an external declaration for -the symbol has already been written. +In an RTL dump, this flag is represented as @samp{/c}. -In a @code{reg}, it is used by the leaf register renumbering code to ensure -that each register is only renumbered once. +@findex frame_related +@cindex @samp{/f} in RTL dump +@item frame_related +In an @code{insn} or @code{set} expression, 1 means that it is part of +a function prologue and sets the stack pointer, sets the frame pointer, +saves a register, or sets up a temporary register to use in place of the +frame pointer. -@findex volatil -@item volatil -This flag is used in @code{mem}, @code{symbol_ref} and @code{reg} -expressions and in insns. In RTL dump files, it is printed as -@samp{/v}. +In @code{reg} expressions, 1 means that the register holds a pointer. -@cindex volatile memory references -In a @code{mem} expression, it is 1 if the memory reference is volatile. -Volatile memory references may not be deleted, reordered or combined. +In @code{symbol_ref} expressions, 1 means that the reference addresses +this function's string constant pool. -In a @code{symbol_ref} expression, it is used for machine-specific -purposes. - -In a @code{reg} expression, it is 1 if the value is a user-level variable. -0 indicates an internal compiler temporary. +In @code{mem} expressions, 1 means that the reference is to a scalar. -In an insn, 1 means the insn has been deleted. +In an RTL dump, this flag is represented as @samp{/f}. @findex in_struct +@cindex @samp{/s} in RTL dump @item in_struct In @code{mem} expressions, it is 1 if the memory datum referred to is all or part of a structure or array; 0 if it is (or might be) a scalar @@ -658,12 +711,6 @@ variable. A reference through a C pointer has 0 because the pointer might point to a scalar variable. This information allows the compiler to determine something about possible cases of aliasing. -In an insn in the delay slot of a branch, 1 means that this insn is from -the target of the branch. - -During instruction scheduling, in an insn, 1 means that this insn must be -scheduled as part of a group together with the previous insn. - In @code{reg} expressions, it is 1 if the register has its entire life contained within the test expression of some loop. @@ -679,9 +726,50 @@ This is used for labels which are the target of non-local gotos. Such a label that would have been deleted is replaced with a @code{note} of type @code{NOTE_INSN_DELETED_LABEL}. +In an @code{insn} during dead-code elimination, 1 means that the insn is +dead code. + +In an @code{insn} during reorg for an insn in the delay slot of a branch, +1 means that this insn is from the target of the branch. + +In an @code{insn} during instruction scheduling, 1 means that this insn +must be scheduled as part of a group together with the previous insn. + In an RTL dump, this flag is represented as @samp{/s}. +@findex integrated +@cindex @samp{/i} in RTL dump +@item integrated +In an @code{insn}, @code{insn_list}, or @code{const}, 1 means the RTL was +produced by procedure integration. + +In @code{reg} expressions, 1 means the register contains +the value to be returned by the current function. On +machines that pass parameters in registers, the same register number +may be used for parameters as well, but this flag is not set on such +uses. + +In @code{symbol_ref} expressions, 1 means the referenced symbol is weak. + +In an RTL dump, this flag is represented as @samp{/i}. + +@findex jump +@cindex @samp{/j} in RTL dump +@item jump +In a @code{mem} expression, 1 means we should keep the alias set for this +mem unchanged when we access a component. + +In a @code{set}, 1 means it is for a return. + +In a @code{call_insn}, 1 means it is a sibling call. + +In the @code{LOG_LINKS} of an @code{insn_list} during scheduling, 1 means the +cost of executing an instruction through the link varies and is unchanging. + +In an RTL dump, this flag is represented as @samp{/j}. + @findex unchanging +@cindex @samp{/u} in RTL dump @item unchanging In @code{reg} and @code{mem} expressions, 1 means that the value of the expression never changes. @@ -689,26 +777,50 @@ that the value of the expression never changes. In @code{subreg} expressions, it is 1 if the @code{subreg} references an unsigned object whose mode has been promoted to a wider mode. -In an insn, 1 means that this is an annulling branch. +In an @code{insn}, 1 means that this is an annulling branch. In a @code{symbol_ref} expression, 1 means that this symbol addresses -something in the per-function constants pool. +something in the per-function constant pool. -In a @code{call_insn}, 1 means that this instruction is a call to a -const function. +In a @code{call_insn}, @code{note}, or an @code{expr_list} of notes, +1 means that this instruction is a call to a const or pure function. In an RTL dump, this flag is represented as @samp{/u}. -@findex integrated -@item integrated -In some kinds of expressions, including insns, this flag means the -rtl was produced by procedure integration. +@findex used +@item used +This flag is used directly (without an access macro) at the end of RTL +generation for a function, to count the number of times an expression +appears in insns. Expressions that appear more than once are copied, +according to the rules for shared structure (@pxref{Sharing}). -In a @code{reg} expression, this flag indicates the register -containing the value to be returned by the current function. On -machines that pass parameters in registers, the same register number -may be used for parameters as well, but this flag is not set on such -uses. +For a @code{reg}, it is used directly (without an access macro) by the +leaf register renumbering code to ensure that each register is only +renumbered once. + +In a @code{symbol_ref}, it indicates that an external declaration for +the symbol has already been written. + +@findex volatil +@cindex @samp{/v} in RTL dump +@item volatil +@cindex volatile memory references +In a @code{mem} or @code{asm_operands} expression, it is 1 if the memory +reference is volatile. Volatile memory references may not be deleted, +reordered or combined. + +In a @code{symbol_ref} expression, it is used for machine-specific +purposes. + +In a @code{reg} expression, it is 1 if the value is a user-level variable. +0 indicates an internal compiler temporary. + +In an @code{insn}, 1 means the insn has been deleted. + +In @code{label_ref} and @code{reg_label} expressions, 1 means a reference +to a non-local label. + +In an RTL dump, this flag is represented as @samp{/v}. @end table @node Machine Modes |