@c Copyright (C) 1988, 1989, 1992, 1994, 1997, 1998, 1999, 2000, 2001, 2002,
-@c 2003, 2004, 2005
+@c 2003, 2004, 2005, 2006, 2007
@c Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
The various expression codes are divided into several @dfn{classes},
which are represented by single characters. You can determine the class
of an RTX code with the macro @code{GET_RTX_CLASS (@var{code})}.
-Currently, @file{rtx.def} defines these classes:
+Currently, @file{rtl.def} defines these classes:
@table @code
@item RTX_OBJ
is an entry in the per-file constant pool; again, there is no associated
front end symbol table entry.
+@findex SYMBOL_REF_CONSTANT
+@item SYMBOL_REF_CONSTANT (@var{x})
+If @samp{CONSTANT_POOL_ADDRESS_P (@var{x})} is true, this is the constant
+pool entry for @var{x}. It is null otherwise.
+
+@findex SYMBOL_REF_DATA
+@item SYMBOL_REF_DATA (@var{x})
+A field of opaque type used to store @code{SYMBOL_REF_DECL} or
+@code{SYMBOL_REF_CONSTANT}.
+
@findex SYMBOL_REF_FLAGS
@item SYMBOL_REF_FLAGS (@var{x})
In a @code{symbol_ref}, this is used to communicate various predicates
This is a multi-bit field accessor that returns the @code{tls_model}
to be used for a thread-local storage symbol. It returns zero for
non-thread-local symbols.
+
+@findex SYMBOL_REF_HAS_BLOCK_INFO_P
+@findex SYMBOL_FLAG_HAS_BLOCK_INFO
+@item SYMBOL_FLAG_HAS_BLOCK_INFO
+Set if the symbol has @code{SYMBOL_REF_BLOCK} and
+@code{SYMBOL_REF_BLOCK_OFFSET} fields.
+
+@findex SYMBOL_REF_ANCHOR_P
+@findex SYMBOL_FLAG_ANCHOR
+@cindex @option{-fsection-anchors}
+@item SYMBOL_FLAG_ANCHOR
+Set if the symbol is used as a section anchor. ``Section anchors''
+are symbols that have a known position within an @code{object_block}
+and that can be used to access nearby members of that block.
+They are used to implement @option{-fsection-anchors}.
+
+If this flag is set, then @code{SYMBOL_FLAG_HAS_BLOCK_INFO} will be too.
@end table
Bits beginning with @code{SYMBOL_FLAG_MACH_DEP} are available for
the target's use.
@end table
+
+@findex SYMBOL_REF_BLOCK
+@item SYMBOL_REF_BLOCK (@var{x})
+If @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})}, this is the
+@samp{object_block} structure to which the symbol belongs,
+or @code{NULL} if it has not been assigned a block.
+
+@findex SYMBOL_REF_BLOCK_OFFSET
+@item SYMBOL_REF_BLOCK_OFFSET (@var{x})
+If @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})}, this is the offset of @var{x}
+from the first object in @samp{SYMBOL_REF_BLOCK (@var{x})}. The value is
+negative if @var{x} has not yet been assigned to a block, or it has not
+been given an offset within that block.
@end table
@node Flags
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{note} and @samp{/i}
processors require such numbers to be padded to twelve bytes, others
to sixteen; this mode is used for either.
+@findex SDmode
+@item SDmode
+``Single Decimal Floating'' mode represents a four byte decimal
+floating point number (as distinct from conventional binary floating
+point).
+
+@findex DDmode
+@item DDmode
+``Double Decimal Floating'' mode represents an eight byte decimal
+floating point number.
+
+@findex TDmode
+@item TDmode
+``Tetra Decimal Floating'' mode represents a sixteen byte decimal
+floating point number all 128 of whose bits are meaningful.
+
@findex TFmode
@item TFmode
``Tetra Floating'' mode represents a sixteen byte floating point number
all 128 of whose bits are meaningful. One common use is the
IEEE quad-precision format.
+@findex QQmode
+@item QQmode
+``Quarter-Fractional'' mode represents a single byte treated as a signed
+fractional number. The default format is ``s.7''.
+
+@findex HQmode
+@item HQmode
+``Half-Fractional'' mode represents a two-byte signed fractional number.
+The default format is ``s.15''.
+
+@findex SQmode
+@item SQmode
+``Single Fractional'' mode represents a four-byte signed fractional number.
+The default format is ``s.31''.
+
+@findex DQmode
+@item DQmode
+``Double Fractional'' mode represents an eight-byte signed fractional number.
+The default format is ``s.63''.
+
+@findex TQmode
+@item TQmode
+``Tetra Fractional'' mode represents a sixteen-byte signed fractional number.
+The default format is ``s.127''.
+
+@findex UQQmode
+@item UQQmode
+``Unsigned Quarter-Fractional'' mode represents a single byte treated as an
+unsigned fractional number. The default format is ``.8''.
+
+@findex UHQmode
+@item UHQmode
+``Unsigned Half-Fractional'' mode represents a two-byte unsigned fractional
+number. The default format is ``.16''.
+
+@findex USQmode
+@item USQmode
+``Unsigned Single Fractional'' mode represents a four-byte unsigned fractional
+number. The default format is ``.32''.
+
+@findex UDQmode
+@item UDQmode
+``Unsigned Double Fractional'' mode represents an eight-byte unsigned
+fractional number. The default format is ``.64''.
+
+@findex UTQmode
+@item UTQmode
+``Unsigned Tetra Fractional'' mode represents a sixteen-byte unsigned
+fractional number. The default format is ``.128''.
+
+@findex HAmode
+@item HAmode
+``Half-Accumulator'' mode represents a two-byte signed accumulator.
+The default format is ``s8.7''.
+
+@findex SAmode
+@item SAmode
+``Single Accumulator'' mode represents a four-byte signed accumulator.
+The default format is ``s16.15''.
+
+@findex DAmode
+@item DAmode
+``Double Accumulator'' mode represents an eight-byte signed accumulator.
+The default format is ``s32.31''.
+
+@findex TAmode
+@item TAmode
+``Tetra Accumulator'' mode represents a sixteen-byte signed accumulator.
+The default format is ``s64.63''.
+
+@findex UHAmode
+@item UHAmode
+``Unsigned Half-Accumulator'' mode represents a two-byte unsigned accumulator.
+The default format is ``8.8''.
+
+@findex USAmode
+@item USAmode
+``Unsigned Single Accumulator'' mode represents a four-byte unsigned
+accumulator. The default format is ``16.16''.
+
+@findex UDAmode
+@item UDAmode
+``Unsigned Double Accumulator'' mode represents an eight-byte unsigned
+accumulator. The default format is ``32.32''.
+
+@findex UTAmode
+@item UTAmode
+``Unsigned Tetra Accumulator'' mode represents a sixteen-byte unsigned
+accumulator. The default format is ``64.64''.
+
@findex CCmode
@item CCmode
``Condition Code'' mode represents the value of a condition code, which
@code{HFmode}, @code{TQFmode}, @code{SFmode}, @code{DFmode},
@code{XFmode} and @code{TFmode}.
+@findex MODE_DECIMAL_FLOAT
+@item MODE_DECIMAL_FLOAT
+Decimal floating point modes. By default these are @code{SDmode},
+@code{DDmode} and @code{TDmode}.
+
+@findex MODE_FRACT
+@item MODE_FRACT
+Signed fractional modes. By default these are @code{QQmode}, @code{HQmode},
+@code{SQmode}, @code{DQmode} and @code{TQmode}.
+
+@findex MODE_UFRACT
+@item MODE_UFRACT
+Unsigned fractional modes. By default these are @code{UQQmode}, @code{UHQmode},
+@code{USQmode}, @code{UDQmode} and @code{UTQmode}.
+
+@findex MODE_ACCUM
+@item MODE_ACCUM
+Signed accumulator modes. By default these are @code{HAmode},
+@code{SAmode}, @code{DAmode} and @code{TAmode}.
+
+@findex MODE_UACCUM
+@item MODE_UACCUM
+Unsigned accumulator modes. By default these are @code{UHAmode},
+@code{USAmode}, @code{UDAmode} and @code{UTAmode}.
+
@findex MODE_COMPLEX_INT
@item MODE_COMPLEX_INT
Complex integer modes. (These are not currently implemented).
@findex MODE_CC
@item MODE_CC
Modes representing condition code values. These are @code{CCmode} plus
-any modes listed in the @code{EXTRA_CC_MODES} macro. @xref{Jump Patterns},
+any @code{CC_MODE} modes listed in the @file{@var{machine}-modes.def}.
+@xref{Jump Patterns},
also see @ref{Condition Code}.
@findex MODE_RANDOM
@item GET_MODE_BITSIZE (@var{m})
Returns the size in bits of a datum of mode @var{m}.
+@findex GET_MODE_IBIT
+@item GET_MODE_IBIT (@var{m})
+Returns the number of integral bits of a datum of fixed-point mode @var{m}.
+
+@findex GET_MODE_FBIT
+@item GET_MODE_FBIT (@var{m})
+Returns the number of fractional bits of a datum of fixed-point mode @var{m}.
+
@findex GET_MODE_MASK
@item GET_MODE_MASK (@var{m})
Returns a bitmask containing 1 for all bits in a word that fit within
@findex VIRTUAL_STACK_VARS_REGNUM
@cindex @code{FRAME_GROWS_DOWNWARD} and virtual registers
@item VIRTUAL_STACK_VARS_REGNUM
-If @code{FRAME_GROWS_DOWNWARD} is defined, this points to immediately
-above the first variable on the stack. Otherwise, it points to the
-first variable on the stack.
+If @code{FRAME_GROWS_DOWNWARD} is defined to a nonzero value, this points
+to immediately above the first variable on the stack. Otherwise, it points
+to the first variable on the stack.
@cindex @code{STARTING_FRAME_OFFSET} and virtual registers
@cindex @code{FRAME_POINTER_REGNUM} and virtual registers
expressions left in the function after CSE, @var{reg} is forced into the
stack and the @code{addressof} expression is replaced with a @code{plus}
expression for the address of its stack slot.
+
+@findex concat
+@item (concat@var{m} @var{rtx} @var{rtx})
+This RTX represents the concatenation of two other RTXs. This is used
+for complex values. It should only appear in the RTL attached to
+declarations and during RTL generation. It should not appear in the
+ordinary insn chain.
+
+@findex concatn
+@item (concatn@var{m} [@var{rtx} ...])
+This RTX represents the concatenation of all the @var{rtx} to make a
+single value. Like @code{concat}, this should only appear in
+declarations, and not in the insn chain.
@end table
@node Arithmetic
still known.
@findex neg
+@findex ss_neg
+@cindex negation
+@cindex negation with signed saturation
@item (neg:@var{m} @var{x})
-Represents the negation (subtraction from zero) of the value represented
-by @var{x}, carried out in mode @var{m}.
+@itemx (ss_neg:@var{m} @var{x})
+These two expressions represent the negation (subtraction from zero) of
+the value represented by @var{x}, carried out in mode @var{m}. They
+differ in the behavior on overflow of integer modes. In the case of
+@code{neg}, the negation of the operand may be a number not representable
+in mode @var{m}, in which case it is truncated to @var{m}. @code{ss_neg}
+ensures that an out-of-bounds result saturates to the maximum or minimum
+representable value.
@findex mult
@cindex multiplication
fixed-point mode.
@findex ashift
+@findex ss_ashift
@cindex left shift
@cindex shift
@cindex arithmetic shift
+@cindex arithmetic shift with signed saturation
@item (ashift:@var{m} @var{x} @var{c})
-Represents the result of arithmetically shifting @var{x} left by @var{c}
-places. @var{x} have mode @var{m}, a fixed-point machine mode. @var{c}
+@itemx (ss_ashift:@var{m} @var{x} @var{c})
+These two expressions represent the result of arithmetically shifting @var{x}
+left by @var{c} places. They differ in their behavior on overflow of integer
+modes. An @code{ashift} operation is a plain shift with no special behavior
+in case of a change in the sign bit; @code{ss_ashift} saturates to the minimum
+or maximum representable value if any of the bits shifted out differs from the
+final sign bit.
+
+@var{x} have mode @var{m}, a fixed-point machine mode. @var{c}
be a fixed-point mode or be a constant with mode @code{VOIDmode}; which
mode is determined by the mode called for in the machine description
entry for the left-shift instruction. For example, on the VAX, the mode
Represents the number of 1-bits modulo 2 in @var{x}, represented as an
integer of mode @var{m}. The mode of @var{x} will usually be an integer
mode.
+
+@findex bswap
+@item (bswap:@var{m} @var{x})
+Represents the value @var{x} with the order of bytes reversed, carried out
+in mode @var{m}, which must be a fixed-point machine mode.
@end table
@node Comparisons
caller-copied (@pxref{Register Arguments, TARGET_CALLEE_COPIES}),
the stack slot will be mentioned in @code{CLOBBER} and @code{USE}
entries; if it's callee-copied, only a @code{USE} will appear, and the
-@code{MEM} may point to addresses that are not stack slots. These
-@code{MEM}s are used only in libcalls, because, unlike regular function
-calls, @code{CONST_CALL}s (which libcalls generally are, @pxref{Flags,
-CONST_CALL_P}) aren't assumed to read and write all memory, so flow
-would consider the stores dead and remove them. Note that, since a
-libcall must never return values in memory (@pxref{Aggregate Return,
-RETURN_IN_MEMORY}), there will never be a @code{CLOBBER} for a memory
-address holding a return value.
+@code{MEM} may point to addresses that are not stack slots.
@code{CLOBBER}ed registers in this list augment registers specified in
@code{CALL_USED_REGISTERS} (@pxref{Register Basics}).
invariants.
@findex NOTE_INSN_FUNCTION_BEG
-@item NOTE_INSN_FUNCTION_END
+@item NOTE_INSN_FUNCTION_BEG
Appears at the start of the function body, after the function
prologue.
-@findex NOTE_INSN_FUNCTION_END
-@item NOTE_INSN_FUNCTION_END
-Appears near the end of the function body, just before the label that
-@code{return} statements jump to (on machine where a single instruction
-does not suffice for returning). This note may be deleted by jump
-optimization.
-
@end table
These codes are printed symbolically when they appear in debugging dumps.
@item LOG_LINKS (@var{i})
A list (chain of @code{insn_list} expressions) giving information about
dependencies between instructions within a basic block. Neither a jump
-nor a label may come between the related insns.
+nor a label may come between the related insns. These are only used by
+the schedulers and by combine. This is a deprecated data structure.
+Def-use and use-def chains are now prefered.
@findex REG_NOTES
@item REG_NOTES (@var{i})
pointer until then. Flow only adds links for those data dependencies
which can be used for instruction combination. For each insn, the flow
analysis pass adds a link to insns which store into registers values
-that are used for the first time in this insn. The instruction
-scheduling pass adds extra links so that every dependence will be
-represented. Links represent data dependencies, antidependencies and
-output dependencies; the machine mode of the link distinguishes these
-three types: antidependencies have mode @code{REG_DEP_ANTI}, output
-dependencies have mode @code{REG_DEP_OUTPUT}, and data dependencies have
-mode @code{VOIDmode}.
+that are used for the first time in this insn.
The @code{REG_NOTES} field of an insn is a chain similar to the
@code{LOG_LINKS} field but it includes @code{expr_list} expressions in
descriptive text.
@table @code
-@findex REG_DEP_ANTI
-@item REG_DEP_ANTI
-This indicates an anti dependence (a write after read dependence).
+@findex REG_DEP_TRUE
+@item REG_DEP_TRUE
+This indicates a true dependence (a read after write dependence).
@findex REG_DEP_OUTPUT
@item REG_DEP_OUTPUT
This indicates an output dependence (a write after write dependence).
+
+@findex REG_DEP_ANTI
+@item REG_DEP_ANTI
+This indicates an anti dependence (a write after read dependence).
+
@end table
These notes describe information gathered from gcov profile data. They
This is used on an RTX_FRAME_RELATED_P insn wherein the attached expression
is used in place of the actual insn pattern. This is done in cases where
the pattern is either complex or misleading.
+
+@findex REG_LIBCALL_ID
+@item REG_LIBCALL_ID
+This is used to specify that an insn is part of a libcall. Each libcall
+in a function has a unique id, and all the insns that are part of that
+libcall will have a REG_LIBCALL_ID note attached with the same ID.
@end table
For convenience, the machine mode in an @code{insn_list} or
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