/* This file contains the definitions and documentation for the
Register Transfer Expressions (rtx's) that make up the
Register Transfer Language (rtl) used in the Back End of the GNU compiler.
- Copyright (C) 1987, 1988, 1992, 1994, 1995, 1997, 1998, 1999, 2000, 2004
+ Copyright (C) 1987, 1988, 1992, 1994, 1995, 1997, 1998, 1999, 2000, 2004,
+ 2005
Free Software Foundation, Inc.
This file is part of GCC.
You should have received a copy of the GNU General Public License
along with GCC; see the file COPYING. If not, write to the Free
-Software Foundation, 59 Temple Place - Suite 330, Boston, MA
-02111-1307, USA. */
+Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
+02110-1301, USA. */
/* Expression definitions and descriptions for all targets are in this file.
DEF_RTL_EXPR(CONST_DOUBLE, "const_double", CONST_DOUBLE_FORMAT, RTX_CONST_OBJ)
/* Describes a vector constant. */
-DEF_RTL_EXPR(CONST_VECTOR, "const_vector", "E", RTX_EXTRA)
+DEF_RTL_EXPR(CONST_VECTOR, "const_vector", "E", RTX_CONST_OBJ)
/* String constant. Used for attributes in machine descriptions and
for special cases in DWARF2 debug output. NOT used for source-
by a SET whose first operand is (PC). */
DEF_RTL_EXPR(PC, "pc", "", RTX_OBJ)
-/* Used in the cselib routines to describe a value. */
+/* Used in the cselib routines to describe a value. Objects of this
+ kind are only allocated in cselib.c, in an alloc pool instead of
+ in GC memory. The only operand of a VALUE is a cselib_val_struct. */
DEF_RTL_EXPR(VALUE, "value", "0", RTX_OBJ)
/* A register. The "operand" is the register number, accessed with
the REGNO macro. If this number is less than FIRST_PSEUDO_REGISTER
than a hardware register is being referred to. The second operand
holds the original register number - this will be different for a
- pseudo register that got turned into a hard register.
+ pseudo register that got turned into a hard register. The third
+ operand points to a reg_attrs structure.
This rtx needs to have as many (or more) fields as a MEM, since we
can change REG rtx's into MEMs during reload. */
DEF_RTL_EXPR(REG, "reg", "i00", RTX_OBJ)
/* Reference to an assembler label in the code for this function.
The operand is a CODE_LABEL found in the insn chain.
- The unprinted fields 1 and 2 are used in flow.c for the
- LABEL_NEXTREF and CONTAINING_INSN. */
-DEF_RTL_EXPR(LABEL_REF, "label_ref", "u00", RTX_CONST_OBJ)
+ The unprinted field 1 is used in flow.c for the LABEL_NEXTREF. */
+DEF_RTL_EXPR(LABEL_REF, "label_ref", "u0", RTX_CONST_OBJ)
/* Reference to a named label:
Operand 0: label name
/* Bitwise operations. */
DEF_RTL_EXPR(AND, "and", "ee", RTX_COMM_ARITH)
-
DEF_RTL_EXPR(IOR, "ior", "ee", RTX_COMM_ARITH)
-
DEF_RTL_EXPR(XOR, "xor", "ee", RTX_COMM_ARITH)
-
DEF_RTL_EXPR(NOT, "not", "e", RTX_UNARY)
/* Operand:
/* Minimum and maximum values of two operands. We need both signed and
unsigned forms. (We cannot use MIN for SMIN because it conflicts
- with a macro of the same name.) */
+ with a macro of the same name.) The signed variants should be used
+ with floating point. Further, if both operands are zeros, or if either
+ operand is NaN, then it is unspecified which of the two operands is
+ returned as the result. */
DEF_RTL_EXPR(SMIN, "smin", "ee", RTX_COMM_ARITH)
DEF_RTL_EXPR(SMAX, "smax", "ee", RTX_COMM_ARITH)
If BITS_BIG_ENDIAN is defined, the first bit is the msb and
operand 2 counts from the msb of the memory unit.
Otherwise, the first bit is the lsb and operand 2 counts from
- the lsb of the memory unit. */
+ the lsb of the memory unit.
+ This kind of expression can not appear as an lvalue in RTL. */
DEF_RTL_EXPR(SIGN_EXTRACT, "sign_extract", "eee", RTX_BITFIELD_OPS)
-/* Similar for unsigned bit-field. */
+/* Similar for unsigned bit-field.
+ But note! This kind of expression _can_ appear as an lvalue. */
DEF_RTL_EXPR(ZERO_EXTRACT, "zero_extract", "eee", RTX_BITFIELD_OPS)
/* For RISC machines. These save memory when splitting insns. */
/* Appears only in define_predicate/define_special_predicate
expressions. Evaluates true only if the operand has an RTX code
- from the set given by the argument (a comma-separated list). */
-DEF_RTL_EXPR(MATCH_CODE, "match_code", "s", RTX_MATCH)
+ from the set given by the argument (a comma-separated list). If the
+ second argument is present and nonempty, it is a sequence of digits
+ and/or letters which indicates the subexpression to test, using the
+ same syntax as genextract/genrecog's location strings: 0-9 for
+ XEXP (op, n), a-z for XVECEXP (op, 0, n); each character applies to
+ the result of the one before it. */
+DEF_RTL_EXPR(MATCH_CODE, "match_code", "ss", RTX_MATCH)
/* Appears only in define_predicate/define_special_predicate
expressions. The argument is a C expression to be injected at this
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