* doc/rtl.texi (Flags): Clean up documentation of RTL flags
From-SVN: r48608
This commit is contained in:
Janis Johnson
Janis Johnson
parent
c7f3e0b01f
commit
0341c5d2c0
@ -1,3 +1,7 @@
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2002-01-07 Janis Johnson <janis187@us.ibm.com>
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* doc/rtl.texi (Flags): Clean up documentation of RTL flags
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2002-01-07 Marek Michalkiewicz <marekm@amelek.gda.pl>
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* config/avr/avr.c (avr_mcu_types): Add new MCU types.
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532
gcc/doc/rtl.texi
532
gcc/doc/rtl.texi
@ -369,60 +369,175 @@ to access them.
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@section Flags in an RTL Expression
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@cindex flags in RTL expression
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RTL expressions contain several flags (one-bit bit-fields) and other
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values that are used in certain types of expression. Most often they
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are accessed with the following macros:
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RTL expressions contain several flags (one-bit bit-fields)
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that are used in certain types of expression. Most often they
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are accessed with the following macros, which expand into lvalues:
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@table @code
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@findex MEM_VOLATILE_P
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@cindex @code{mem} and @samp{/v}
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@cindex @code{volatil}, in @code{mem}
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@cindex @samp{/v} in RTL dump
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@item MEM_VOLATILE_P (@var{x})
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In @code{mem} expressions, nonzero for volatile memory references.
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@findex CONSTANT_POOL_ADDRESS_P
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@cindex @code{symbol_ref} and @samp{/u}
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@cindex @code{unchanging}, in @code{symbol_ref}
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@item CONSTANT_POOL_ADDRESS_P (@var{x})
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Nonzero in a @code{symbol_ref} if it refers to part of the current
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function's constant pool. For most targets these addresses are in a
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@code{.rodata} section entirely separate from the function, but for
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some targets the addresses are close to the beginning of the function.
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In either case GCC assumes these addresses can be addressed directly,
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perhaps with the help of base registers.
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Stored in the @code{unchanging} field and printed as @samp{/u}.
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@findex CONST_OR_PURE_CALL_P
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@cindex @code{call_insn} and @samp{/u}
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@cindex @code{unchanging}, in @code{call_insn}
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@item CONST_OR_PURE_CALL_P (@var{x})
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In a @code{call_insn}, @code{note}, or an @code{expr_list} for notes,
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indicates that the insn represents a call to a const or pure function.
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Stored in the @code{unchanging} field and printed as @samp{/u}.
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@findex INSN_ANNULLED_BRANCH_P
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@cindex @code{insn} and @samp{/u}
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@cindex @code{unchanging}, in @code{insn}
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@item INSN_ANNULLED_BRANCH_P (@var{x})
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In an @code{insn} in the delay slot of a branch insn, indicates that an
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annulling branch should be used. See the discussion under
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@code{sequence} below. Stored in the @code{unchanging} field and printed
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as @samp{/u}.
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@findex INSN_DEAD_CODE_P
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@cindex @code{insn} and @samp{/s}
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@cindex @code{in_struct}, in @code{insn}
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@item INSN_DEAD_CODE_P (@var{x})
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In an @code{insn} during the dead-code elimination pass, nonzero if the
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insn is dead.
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Stored in the @code{in_struct} field and printed as @samp{/s}.
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@findex INSN_DELETED_P
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@cindex @code{insn} and @samp{/v}
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@cindex @code{volatil}, in @code{insn}
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@item INSN_DELETED_P (@var{x})
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In an @code{insn}, nonzero if the insn has been deleted. Stored in the
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@code{volatil} field and printed as @samp{/v}.
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@findex INSN_FROM_TARGET_P
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@cindex @code{insn} and @samp{/s}
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@cindex @code{in_struct}, in @code{insn}
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@item INSN_FROM_TARGET_P (@var{x})
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In an @code{insn} in a delay slot of a branch, indicates that the insn
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is from the target of the branch. If the branch insn has
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@code{INSN_ANNULLED_BRANCH_P} set, this insn will only be executed if
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the branch is taken. For annulled branches with
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@code{INSN_FROM_TARGET_P} clear, the insn will be executed only if the
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branch is not taken. When @code{INSN_ANNULLED_BRANCH_P} is not set,
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this insn will always be executed. Stored in the @code{in_struct}
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field and printed as @samp{/s}.
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@findex LABEL_OUTSIDE_LOOP_P
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@cindex @code{label_ref} and @samp{/s}
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@cindex @code{in_struct}, in @code{label_ref}
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@item LABEL_OUTSIDE_LOOP_P (@var{x})
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In @code{label_ref} expressions, nonzero if this is a reference to a
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label that is outside the innermost loop containing the reference to the
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label. Stored in the @code{in_struct} field and printed as @samp{/s}.
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@findex LABEL_PRESERVE_P
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@cindex @code{code_label} and @samp{/i}
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@cindex @code{in_struct}, in @code{code_label}
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@item LABEL_PRESERVE_P (@var{x})
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In a @code{code_label}, indicates that the label is referenced by
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code or data not visible to the RTL of a given function.
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Labels referenced by a non-local goto will have this bit set. Stored
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in the @code{in_struct} field and printed as @samp{/s}.
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@findex LABEL_REF_NONLOCAL_P
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@cindex @code{label_ref} and @samp{/v}
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@cindex @code{volatil}, in @code{label_ref}
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@item LABEL_REF_NONLOCAL_P (@var{x})
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In @code{label_ref} and @code{reg_label} expressions, nonzero if this is
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a reference to a non-local label.
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Stored in the @code{volatil} field and printed as @samp{/v}.
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@findex LINK_COST_FREE
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@cindex @code{insn_list} and @samp{/c}
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@cindex @code{call}, in @code{insn_list}
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@item LINK_COST_FREE (@var{x})
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In the @code{LOG_LINKS} @code{insn_list} during scheduling, nonzero when
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the cost of executing an instruction through the link is zero, i.e., the
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link makes the cost free. Stored in the @code{call} field and printed
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as @samp{/c}.
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@findex LINK_COST_ZERO
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@cindex @code{insn_list} and @samp{/j}
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@cindex @code{jump}, in @code{insn_list}
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@item LINK_COST_ZERO (@var{x})
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In the @code{LOG_LINKS} @code{insn_list} during scheduling, nonzero when
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the cost of executing an instruction through the link varies and is
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unchanged, i.e., the link has zero additional cost.
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Stored in the @code{jump} field and printed as @samp{/j}.
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@findex MEM_IN_STRUCT_P
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@cindex @code{mem} and @samp{/s}
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@cindex @code{in_struct}, in @code{mem}
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@cindex @samp{/s} in RTL dump
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@item MEM_IN_STRUCT_P (@var{x})
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In @code{mem} expressions, nonzero for reference to an entire structure,
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union or array, or to a component of one. Zero for references to a
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scalar variable or through a pointer to a scalar. Stored in the
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@code{in_struct} field and printed as @samp{/s}. If both this flag and
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MEM_SCALAR_P are clear, then we don't know whether this MEM is in a
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structure or not. Both flags should never be simultaneously set.
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scalar variable or through a pointer to a scalar. If both this flag and
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@code{MEM_SCALAR_P} are clear, then we don't know whether this @code{mem}
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is in a structure or not. Both flags should never be simultaneously set.
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Stored in the @code{in_struct} field and printed as @samp{/s}.
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@findex MEM_KEEP_ALIAS_SET_P
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@cindex @code{mem} and @samp{/j}
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@cindex @code{jump}, in @code{mem}
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@item MEM_KEEP_ALIAS_SET_P (@var{x})
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In @code{mem} expressions, 1 if we should keep the alias set for this
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mem unchanged when we access a component. Set to 1, for example, when we
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are already in a non-addressable component of an aggregate.
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Stored in the @code{jump} field and printed as @samp{/j}.
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@findex MEM_SCALAR_P
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@cindex @code{mem} and @samp{/f}
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@cindex @code{frame_related}, in@code{mem}
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@cindex @samp{/f} in RTL dump
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@cindex @code{frame_related}, in @code{mem}
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@item MEM_SCALAR_P (@var{x})
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In @code{mem} expressions, nonzero for reference to a scalar known not
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to be a member of a structure, union, or array. Zero for such
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references and for indirections through pointers, even pointers pointing
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to scalar types. If both this flag and MEM_STRUCT_P are clear, then we
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don't know whether this MEM is in a structure or not. Both flags should
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to scalar types. If both this flag and @code{MEM_STRUCT_P} are clear, then we
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don't know whether this @code{mem} is in a structure or not. Both flags should
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never be simultaneously set.
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Stored in the @code{frame_related} field and printed as @samp{/f}.
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@findex MEM_ALIAS_SET
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@item MEM_ALIAS_SET (@var{x})
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In @code{mem} expressions, the alias set to which @var{x} belongs. If
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zero, @var{x} is not in any alias set, and may alias anything. If
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nonzero, @var{x} may only alias objects in the same alias set. This
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value is set (in a language-specific manner) by the front end. This
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field is not a bit-field; it is in an integer, found as the second
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argument to the @code{mem}.
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@findex MEM_VOLATILE_P
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@cindex @code{mem} and @samp{/v}
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@cindex @code{volatil}, in @code{mem}
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@item MEM_VOLATILE_P (@var{x})
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In @code{mem} and @code{asm_operands} expressions, nonzero for volatile
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memory references.
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Stored in the @code{volatil} field and printed as @samp{/v}.
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@findex REG_FUNCTION_VALUE_P
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@cindex @code{reg} and @samp{/i}
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@cindex @code{integrated}, in @code{reg}
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@item REG_FUNCTION_VALUE_P (@var{x})
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Nonzero in a @code{reg} if it is the place in which this function's
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value is going to be returned. (This happens only in a hard
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register.) Stored in the @code{integrated} field and printed as
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@samp{/i}.
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@findex REG_LOOP_TEST_P
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@cindex @code{reg} and @samp{/s}
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@cindex @code{in_struct}, in @code{reg}
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@item REG_LOOP_TEST_P
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@item REG_LOOP_TEST_P (@var{x})
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In @code{reg} expressions, nonzero if this register's entire life is
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contained in the exit test code for some loop. Stored in the
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@code{in_struct} field and printed as @samp{/s}.
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@findex REG_POINTER
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@cindex @code{reg} and @samp{/f}
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@cindex @code{frame_related}, in @code{reg}
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@item REG_POINTER (@var{x})
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Nonzero in a @code{reg} if the register holds a pointer. Stored in the
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@code{frame_related} field and printed as @samp{/f}.
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@findex REG_USERVAR_P
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@cindex @code{reg} and @samp{/v}
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@cindex @code{volatil}, in @code{reg}
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@ -432,75 +547,19 @@ the user's source code. Zero for temporaries generated internally by
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the compiler. Stored in the @code{volatil} field and printed as
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@samp{/v}.
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@cindex @samp{/i} in RTL dump
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@findex REG_FUNCTION_VALUE_P
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@cindex @code{reg} and @samp{/i}
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@cindex @code{integrated}, in @code{reg}
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@item REG_FUNCTION_VALUE_P (@var{x})
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Nonzero in a @code{reg} if it is the place in which this function's
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value is going to be returned. (This happens only in a hard
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register.) Stored in the @code{integrated} field and printed as
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@samp{/i}.
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The same hard register may be used also for collecting the values of
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functions called by this one, but @code{REG_FUNCTION_VALUE_P} is zero
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in this kind of use.
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@cindex @samp{/f} in RTL dump
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@findex REG_POINTER
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@cindex @code{reg} and @samp{/f}
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@cindex @code{frame_related}, in @code{reg}
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@item REG_POINTER (@var{x})
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Nonzero in a @code{reg} if the register holds a pointer. Stored in the
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@code{frame_related} field and printed as @samp{/f}.
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@findex SUBREG_PROMOTED_VAR_P
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@cindex @code{subreg} and @samp{/s}
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@cindex @code{in_struct}, in @code{subreg}
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@item SUBREG_PROMOTED_VAR_P
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Nonzero in a @code{subreg} if it was made when accessing an object that
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was promoted to a wider mode in accord with the @code{PROMOTED_MODE} machine
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description macro (@pxref{Storage Layout}). In this case, the mode of
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the @code{subreg} is the declared mode of the object and the mode of
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@code{SUBREG_REG} is the mode of the register that holds the object.
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Promoted variables are always either sign- or zero-extended to the wider
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mode on every assignment. Stored in the @code{in_struct} field and
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printed as @samp{/s}.
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@findex SUBREG_PROMOTED_UNSIGNED_P
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@cindex @code{subreg} and @samp{/u}
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@cindex @code{unchanging}, in @code{subreg}
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@item SUBREG_PROMOTED_UNSIGNED_P
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Nonzero in a @code{subreg} that has @code{SUBREG_PROMOTED_VAR_P} nonzero
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if the object being referenced is kept zero-extended and zero if it
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is kept sign-extended. Stored in the @code{unchanging} field and
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printed as @samp{/u}.
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@findex RTX_UNCHANGING_P
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@cindex @code{reg} and @samp{/u}
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@cindex @code{mem} and @samp{/u}
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@cindex @code{unchanging}, in @code{reg} and @code{mem}
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@cindex @samp{/u} in RTL dump
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@item RTX_UNCHANGING_P (@var{x})
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Nonzero in a @code{reg} or @code{mem} if the value is not changed.
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(This flag is not set for memory references via pointers to constants.
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Such pointers only guarantee that the object will not be changed
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explicitly by the current function. The object might be changed by
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other functions or by aliasing.) Stored in the
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@code{unchanging} field and printed as @samp{/u}.
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@findex RTX_INTEGRATED_P
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@cindex @code{integrated}, in @code{insn}
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@item RTX_INTEGRATED_P (@var{insn})
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Nonzero in an insn if it resulted from an in-line function call.
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Stored in the @code{integrated} field and printed as @samp{/i}.
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@findex RTX_FRAME_RELATED_P
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@cindex @code{insn} and @samp{/f}
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@cindex @code{frame_related}, in @code{insn}
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@item RTX_FRAME_RELATED_P (@var{x})
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Nonzero in an insn or expression which is part of a function prologue
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Nonzero in an @code{insn} or @code{set} which is part of a function prologue
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and sets the stack pointer, sets the frame pointer, or saves a register.
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This flag should also be set on an instruction that sets up a temporary
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register to use in place of the frame pointer.
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Stored in the @code{frame_related} field and printed as @samp{/f}.
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In particular, on RISC targets where there are limits on the sizes of
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immediate constants, it is sometimes impossible to reach the register
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@ -521,12 +580,77 @@ computation performed by this instruction, i.e., one that
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This flag is required for exception handling support on targets with RTL
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prologues.
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@findex SYMBOL_REF_USED
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@cindex @code{used}, in @code{symbol_ref}
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@item SYMBOL_REF_USED (@var{x})
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In a @code{symbol_ref}, indicates that @var{x} has been used. This is
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normally only used to ensure that @var{x} is only declared external
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once. Stored in the @code{used} field.
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@findex RTX_INTEGRATED_P
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@cindex @code{insn} and @samp{/i}
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@cindex @code{integrated}, in @code{insn}
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@item RTX_INTEGRATED_P (@var{x})
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Nonzero in an @code{insn}, @code{insn_list}, or @code{const} if it
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resulted from an in-line function call.
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Stored in the @code{integrated} field and printed as @samp{/i}.
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@findex RTX_UNCHANGING_P
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@cindex @code{reg} and @samp{/u}
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@cindex @code{mem} and @samp{/u}
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@cindex @code{unchanging}, in @code{reg} and @code{mem}
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@item RTX_UNCHANGING_P (@var{x})
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Nonzero in a @code{reg} or @code{mem} if the memory is set at most once,
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anywhere. This does not mean that it is function invariant.
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Stored in the @code{unchanging} field and printed as @samp{/u}.
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@findex SCHED_GROUP_P
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@cindex @code{insn} and @samp{/i}
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@cindex @code{in_struct}, in @code{insn}
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@item SCHED_GROUP_P (@var{x})
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During instruction scheduling, in an @code{insn}, indicates that the
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previous insn must be scheduled together with this insn. This is used to
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ensure that certain groups of instructions will not be split up by the
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instruction scheduling pass, for example, @code{use} insns before
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a @code{call_insn} may not be separated from the @code{call_insn}.
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Stored in the @code{in_struct} field and printed as @samp{/s}.
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@findex SET_IS_RETURN_P
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@cindex @code{insn} and @samp{/j}
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@cindex @code{jump}, in @code{insn}
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@item SET_IS_RETURN_P (@var{x})
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For a @code{set}, nonzero if it is for a return.
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Stored in the @code{jump} field and printed as @samp{/j}.
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@findex SIBLING_CALL_P
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@cindex @code{call_insn} and @samp{/j}
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@cindex @code{jump}, in @code{call_insn}
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@item SIBLING_CALL_P (@var{x})
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For a @code{call_insn}, nonzero if the insn is a sibling call.
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Stored in the @code{jump} field and printed as @samp{/j}.
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@findex STRING_POOL_ADDRESS_P
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@cindex @code{symbol_ref} and @samp{/f}
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@cindex @code{frame_related}, in @code{symbol_ref}
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@item STRING_POOL_ADDRESS_P (@var{x})
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For a @code{symbol_ref} expression, nonzero if it addresses this function's
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string constant pool.
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Stored in the @code{frame_related} field and printed as @samp{/f}.
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@findex SUBREG_PROMOTED_UNSIGNED_P
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@cindex @code{subreg} and @samp{/u}
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@cindex @code{unchanging}, in @code{subreg}
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@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 @code{mem} expressions, 1 means that the reference is to a scalar.
|
||||
|
||||
In a @code{reg} expression, it is 1 if the value is a user-level variable.
|
||||
0 indicates an internal compiler temporary.
|
||||
|
||||
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
|
||||
|
||||
Loading…
Reference in New Issue
Block a user