irarch.h File Reference

Some machine dependent optimizations. More...

#include "firm_types.h"
#include "begin.h"
#include "end.h"

Go to the source code of this file.

Data Structures
struct	ir_settings_arch_dep_t
	A parameter structure that drives the machine dependent Firm optimizations. More...

Typedefs
typedef int(*	evaluate_costs_func )(insn_kind kind, const ir_mode *mode, ir_tarval *tv)
	A Callback for evaluating the costs of an instruction.
typedef const ir_settings_arch_dep_t *(*	arch_dep_params_factory_t )(void)
	A factory function, that provides architecture parameters for machine dependent optimizations.

Enumerations
enum	insn_kind {   LEA, SHIFT, SUB, ADD,   ZERO, MUL, ROOT }
	The Multiplication replacement can consist of the following instructions. More...
enum	arch_dep_opts_t { arch_dep_none = 0, arch_dep_mul_to_shift = 1, arch_dep_div_by_const = 2, arch_dep_mod_by_const = 4 }
	Optimization flags. More...

Functions
void	arch_dep_set_opts (arch_dep_opts_t opts)
	Sets the optimizations that shall be applied.
ir_node *	arch_dep_replace_mul_with_shifts (ir_node *irn)
	Replaces Muls with Lea/Shifts/Add/Subs if these have smaller costs than the original multiplication.
ir_node *	arch_dep_replace_div_by_const (ir_node *irn)
	Replaces Divs with Shifts and Add/Subs and Mulh.
ir_node *	arch_dep_replace_mod_by_const (ir_node *irn)
	Replaces Mods with Shifts and Add/Subs and Mulh.

Detailed Description

Some machine dependent optimizations.

Date

1.10.2004

Author

Sebastian Hack

Definition in file irarch.h.

Typedef Documentation

typedef const ir_settings_arch_dep_t*(* arch_dep_params_factory_t)(void)

A factory function, that provides architecture parameters for machine dependent optimizations.

Definition at line 80 of file irarch.h.

typedef int(* evaluate_costs_func)(insn_kind kind, const ir_mode *mode, ir_tarval *tv)

A Callback for evaluating the costs of an instruction.

Parameters

kind	the instruction
mode	the mode of the instruction
tv	for MUL instruction, the multiplication constant

Returns

the costs of this instruction

Definition at line 54 of file irarch.h.

Enumeration Type Documentation

enum arch_dep_opts_t

Optimization flags.

Enumerator:

arch_dep_mul_to_shift	optimize Mul into Shift/Add/Sub
arch_dep_div_by_const	optimize Div into Shift/Add/Mulh
arch_dep_mod_by_const	optimize Mod into Shift/Add/Mulh

Definition at line 85 of file irarch.h.

enum insn_kind

The Multiplication replacement can consist of the following instructions.

Enumerator:

LEA	the LEA instruction
SHIFT	the SHIFT instruction
SUB	the SUB instruction
ADD	the ADD instruction
ZERO	creates a ZERO constant
MUL	the original MUL instruction
ROOT	the ROOT value that is multiplied

Definition at line 35 of file irarch.h.

Function Documentation

ir_node* arch_dep_replace_div_by_const

(

ir_node *

irn

)

Replaces Divs with Shifts and Add/Subs and Mulh.

This function is driven by the 3 parameters:

• allow_mulhu
• allow_mulhs
• max_bits_for_mulh

If irn is a Div with a Const, the constant is inspected if it meets the requirements of the variables stated above. If a Shl/Add/Sub/Mulh sequence can be generated that meets these requirements, this expression is returned. In each other case irn is returned unmodified.

Parameters

irn	The Firm node to inspect.

Returns

A replacement expression for irn.

ir_node* arch_dep_replace_mod_by_const

(

ir_node *

irn

)

Replaces Mods with Shifts and Add/Subs and Mulh.

This function is driven by the 3 parameters:

• allow_mulhu
• allow_mulhs
• max_bits_for_mulh

If irn is a Mod with a Const, the constant is inspected if it meets the requirements of the variables stated above. If a Shl/Add/Sub/Mulh sequence can be generated that meets these requirements, this expression is returned. In each other case irn is returned unmodified.

Parameters

irn	The Firm node to inspect.

Returns

A replacement expression for irn.

ir_node* arch_dep_replace_mul_with_shifts

(

ir_node *

irn

)

Replaces Muls with Lea/Shifts/Add/Subs if these have smaller costs than the original multiplication.

Parameters

irn	The Firm node to inspect.

Returns

A replacement expression for irn.

void arch_dep_set_opts

(

arch_dep_opts_t

opts

)

Sets the optimizations that shall be applied.

Parameters

opts	An optimization bit mask.