+/* Definition of a register operand constraint. This simply maps the
+ constraint string to a register class.
+
+ Operand:
+ 0: The name of the constraint (often, but not always, a single letter).
+ 1: A C expression which evaluates to the appropriate register class for
+ this constraint. If this is not just a constant, it should look only
+ at -m switches and the like.
+ 2: A docstring for this constraint, in Texinfo syntax; not currently
+ used, in future will be incorporated into the manual's list of
+ machine-specific operand constraints. */
+DEF_RTL_EXPR(DEFINE_REGISTER_CONSTRAINT, "define_register_constraint", "sss", RTX_EXTRA)
+
+/* Definition of a non-register operand constraint. These look at the
+ operand and decide whether it fits the constraint.
+
+ DEFINE_CONSTRAINT gets no special treatment if it fails to match.
+ It is appropriate for constant-only constraints, and most others.
+
+ DEFINE_MEMORY_CONSTRAINT tells reload that this constraint can be made
+ to match, if it doesn't already, by converting the operand to the form
+ (mem (reg X)) where X is a base register. It is suitable for constraints
+ that describe a subset of all memory references.
+
+ DEFINE_ADDRESS_CONSTRAINT tells reload that this constraint can be made
+ to match, if it doesn't already, by converting the operand to the form
+ (reg X) where X is a base register. It is suitable for constraints that
+ describe a subset of all address references.
+
+ When in doubt, use plain DEFINE_CONSTRAINT.
+
+ Operand:
+ 0: The name of the constraint (often, but not always, a single letter).
+ 1: A docstring for this constraint, in Texinfo syntax; not currently
+ used, in future will be incorporated into the manual's list of
+ machine-specific operand constraints.
+ 2: A boolean expression which computes whether or not the constraint
+ matches. It should follow the same rules as a define_predicate
+ expression, including the bit about specifying the set of RTX codes
+ that could possibly match. MATCH_TEST subexpressions may make use of
+ these variables:
+ `op' - the RTL object defining the operand.
+ `mode' - the mode of `op'.
+ `ival' - INTVAL(op), if op is a CONST_INT.
+ `hval' - CONST_DOUBLE_HIGH(op), if op is an integer CONST_DOUBLE.
+ `lval' - CONST_DOUBLE_LOW(op), if op is an integer CONST_DOUBLE.
+ `rval' - CONST_DOUBLE_REAL_VALUE(op), if op is a floating-point
+ CONST_DOUBLE.
+ Do not use ival/hval/lval/rval if op is not the appropriate kind of
+ RTL object. */
+DEF_RTL_EXPR(DEFINE_CONSTRAINT, "define_constraint", "sse", RTX_EXTRA)
+DEF_RTL_EXPR(DEFINE_MEMORY_CONSTRAINT, "define_memory_constraint", "sse", RTX_EXTRA)
+DEF_RTL_EXPR(DEFINE_ADDRESS_CONSTRAINT, "define_address_constraint", "sse", RTX_EXTRA)
+
+