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GNU Info (gcc-295.info)Constant AttributesConstant Attributes ------------------- A special form of `define_attr', where the expression for the default value is a `const' expression, indicates an attribute that is constant for a given run of the compiler. Constant attributes may be used to specify which variety of processor is used. For example, (define_attr "cpu" "m88100,m88110,m88000" (const (cond [(symbol_ref "TARGET_88100") (const_string "m88100") (symbol_ref "TARGET_88110") (const_string "m88110")] (const_string "m88000")))) (define_attr "memory" "fast,slow" (const (if_then_else (symbol_ref "TARGET_FAST_MEM") (const_string "fast") (const_string "slow")))) The routine generated for constant attributes has no parameters as it does not depend on any particular insn. RTL expressions used to define the value of a constant attribute may use the `symbol_ref' form, but may not use either the `match_operand' form or `eq_attr' forms involving insn attributes. automatically generated by info2www version 1.2.2.9 |