rtx_iv Class Reference

#include <cfgloop.h>

Collaboration diagram for rtx_iv:

Data Fields
rtx	base
rtx	step
enum iv_extend_code	extend
rtx	delta
rtx	mult
scalar_int_mode	extend_mode
scalar_int_mode	mode
unsigned	first_special: 1

Detailed Description

Induction variable analysis.   

The description of induction variable.  The things are a bit complicated
due to need to handle subregs and extends.  The value of the object described
by it can be obtained as follows (all computations are done in extend_mode):

Value in i-th iteration is
  delta + mult * extend_{extend_mode} (subreg_{mode} (base + i * step)).

If first_special is true, the value in the first iteration is
  delta + mult * base

If extend = UNKNOWN, first_special must be false, delta 0, mult 1 and value is
  subreg_{mode} (base + i * step)

The get_iv_value function can be used to obtain these expressions.

??? Add a third mode field that would specify the mode in that inner
computation is done, which would enable it to be different from the
outer one?   

Field Documentation

base

rtx rtx_iv::base

delta

rtx rtx_iv::delta

Referenced by iv_number_of_iterations().

extend

enum iv_extend_code rtx_iv::extend

extend_mode

scalar_int_mode rtx_iv::extend_mode

first_special

unsigned rtx_iv::first_special

mode

scalar_int_mode rtx_iv::mode

Referenced by biv_p(), canon_condition(), implies_p(), iv_analyze(), iv_analyze_def(), iv_analyze_expr(), iv_analyze_op(), iv_number_of_iterations(), and shorten_into_mode().

mult

rtx rtx_iv::mult

step

rtx rtx_iv::step

Referenced by iv_number_of_iterations().

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The documentation for this class was generated from the following file:

• cfgloop.h