@c Copyright (C) 1988, 1989, 1992, 1994, 1997, 1998, 1999, 2000, 2001, 2002,
-@c 2003, 2004, 2005, 2006, 2007, 2008, 2010
+@c 2003, 2004, 2005, 2006, 2007, 2008, 2010, 2011
@c Free Software Foundation, Inc.
@c This is part of the GCC manual.
@c For copying conditions, see the file gcc.texi.
or another @code{COMPONENT_REF}, or null if there is no compile-time
object associated with the reference.
+@findex MEM_OFFSET_KNOWN_P
+@item MEM_OFFSET_KNOWN_P (@var{x})
+True if the offset of the memory reference from @code{MEM_EXPR} is known.
+@samp{MEM_OFFSET (@var{x})} provides the offset if so.
+
@findex MEM_OFFSET
@item MEM_OFFSET (@var{x})
-The offset from the start of @code{MEM_EXPR} as a @code{CONST_INT} rtx.
+The offset from the start of @code{MEM_EXPR}. The value is only valid if
+@samp{MEM_OFFSET_KNOWN_P (@var{x})} is true.
+
+@findex MEM_SIZE_KNOWN_P
+@item MEM_SIZE_KNOWN_P (@var{x})
+True if the size of the memory reference is known.
+@samp{MEM_SIZE (@var{x})} provides its size if so.
@findex MEM_SIZE
@item MEM_SIZE (@var{x})
-The size in bytes of the memory reference as a @code{CONST_INT} rtx.
+The size in bytes of the memory reference.
This is mostly relevant for @code{BLKmode} references as otherwise
-the size is implied by the mode.
+the size is implied by the mode. The value is only valid if
+@samp{MEM_SIZE_KNOWN_P (@var{x})} is true.
@findex MEM_ALIGN
@item MEM_ALIGN (@var{x})
a reference to a non-local label.
Stored in the @code{volatil} field and printed as @samp{/v}.
-@findex MEM_IN_STRUCT_P
-@cindex @code{mem} and @samp{/s}
-@cindex @code{in_struct}, in @code{mem}
-@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. 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}
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{/i}
-@cindex @code{return_val}, 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 @code{MEM_IN_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{return_val} field and printed as @samp{/i}.
-
@findex MEM_VOLATILE_P
@cindex @code{mem} and @samp{/v}
@cindex @code{asm_input} and @samp{/v}
@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
-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 @code{reg} expressions, it is 1 if the register has its entire life
contained within the test expression of some loop.
may be used for parameters as well, but this flag is not set on such
uses.
-In @code{mem} expressions, 1 means the memory reference is to a scalar
-known not to be a member of a structure, union, or array.
-
In @code{symbol_ref} expressions, 1 means the referenced symbol is weak.
In @code{call} expressions, 1 means the call is pure.
@item (ffs:@var{m} @var{x})
Represents one plus the index of the least significant 1-bit in
@var{x}, represented as an integer of mode @var{m}. (The value is
-zero if @var{x} is zero.) The mode of @var{x} need not be @var{m};
-depending on the target machine, various mode combinations may be
-valid.
+zero if @var{x} is zero.) The mode of @var{x} must be @var{m}
+or @code{VOIDmode}.
@findex clrsb
@item (clrsb:@var{m} @var{x})
represented as an integer of mode @var{m}, starting at the most
significant bit position. This is one less than the number of leading
sign bits (either 0 or 1), with no special cases. The mode of @var{x}
-will usually be an integer mode and may differ from @var{m}.
+must be @var{m} or @code{VOIDmode}.
@findex clz
@item (clz:@var{m} @var{x})
If @var{x} is zero, the value is determined by
@code{CLZ_DEFINED_VALUE_AT_ZERO} (@pxref{Misc}). Note that this is one of
the few expressions that is not invariant under widening. The mode of
-@var{x} will usually be an integer mode.
+@var{x} must be @var{m} or @code{VOIDmode}.
@findex ctz
@item (ctz:@var{m} @var{x})
If @var{x} is zero, the value is determined by
@code{CTZ_DEFINED_VALUE_AT_ZERO} (@pxref{Misc}). Except for this case,
@code{ctz(x)} is equivalent to @code{ffs(@var{x}) - 1}. The mode of
-@var{x} will usually be an integer mode.
+@var{x} must be @var{m} or @code{VOIDmode}.
@findex popcount
@item (popcount:@var{m} @var{x})
Represents the number of 1-bits in @var{x}, represented as an integer of
-mode @var{m}. The mode of @var{x} will usually be an integer mode.
+mode @var{m}. The mode of @var{x} must be @var{m} or @code{VOIDmode}.
@findex parity
@item (parity:@var{m} @var{x})
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.
+integer of mode @var{m}. The mode of @var{x} must be @var{m} or
+@code{VOIDmode}.
@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.
+The mode of @var{x} must be @var{m} or @code{VOIDmode}.
@end table
@node Comparisons
Note that an insn pattern of @code{(return)} is logically equivalent to
@code{(set (pc) (return))}, but the latter form is never used.
+@findex simple_return
+@item (simple_return)
+Like @code{(return)}, but truly represents only a function return, while
+@code{(return)} may represent an insn that also performs other functions
+of the function epilogue. Like @code{(return)}, this may also occur in
+conditional jumps.
+
@findex call
@item (call @var{function} @var{nargs})
Represents a function call. @var{function} is a @code{mem} expression
brackets stand for a vector; the operand of @code{parallel} is a
vector of expressions. @var{x0}, @var{x1} and so on are individual
side effect expressions---expressions of code @code{set}, @code{call},
-@code{return}, @code{clobber} or @code{use}.
+@code{return}, @code{simple_return}, @code{clobber} or @code{use}.
``In parallel'' means that first all the values used in the individual
side-effects are computed, and second all the actual side-effects are
@table @code
@findex PATTERN
@item PATTERN (@var{i})
-An expression for the side effect performed by this insn. This must be
-one of the following codes: @code{set}, @code{call}, @code{use},
-@code{clobber}, @code{return}, @code{asm_input}, @code{asm_output},
-@code{addr_vec}, @code{addr_diff_vec}, @code{trap_if}, @code{unspec},
-@code{unspec_volatile}, @code{parallel}, @code{cond_exec}, or @code{sequence}. If it is a @code{parallel},
-each element of the @code{parallel} must be one these codes, except that
-@code{parallel} expressions cannot be nested and @code{addr_vec} and
-@code{addr_diff_vec} are not permitted inside a @code{parallel} expression.
+An expression for the side effect performed by this insn. This must
+be one of the following codes: @code{set}, @code{call}, @code{use},
+@code{clobber}, @code{return}, @code{simple_return}, @code{asm_input},
+@code{asm_output}, @code{addr_vec}, @code{addr_diff_vec},
+@code{trap_if}, @code{unspec}, @code{unspec_volatile},
+@code{parallel}, @code{cond_exec}, or @code{sequence}. If it is a
+@code{parallel}, each element of the @code{parallel} must be one these
+codes, except that @code{parallel} expressions cannot be nested and
+@code{addr_vec} and @code{addr_diff_vec} are not permitted inside a
+@code{parallel} expression.
@findex INSN_CODE
@item INSN_CODE (@var{i})
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