rtx structure

[Bharati Bhole]

On 11/2/06, Andrew Haley <aph@redhat.com> wrote:
> Bharati Bhole writes:
>  > On 11/2/06, Daniel Berlin <dberlin@dberlin.org> wrote:
>  > > > I want to know what part of rtx each field in this structure stores.
>  > > > While tracing through gdb i tried to print the rtx, and i was not able
>  > > > to understand that. Could u please explain me it with a sample RTX
>  > > > that what value these fields have.
>  > > >
>  > >
>  > > The macros used to access the rtl fields in rtl.h explain what part of
>  > > each field they access and what they treat that object as.
>  > >
>  > > The definitions of rtl in rtl.def define what each portion of a piece
>  > > of valid RTL is structured as.
>  > > > Bharati.
>  > > >
>  > >
>  >
>  > I have gone through the structure but i still dont get it.
>  > Could anybody please tell me, if the following insn is  a sample insn,
>  > how will the rtx structure look like -
>  >         (define_insn "subsi3_carry_zext"
>  >         [(set (match_operand:DI 0 "register_operand" "=rm,r")
>  >                  (zero_extend:DI
>  >                (minus:SI (match_operand:SI 1 "register_operand" "0,0")
>  >                           (plus:SI (match_operand:SI 3
>  > "ix86_carry_flag_operator" "")
>  >                               (match_operand:SI 2 "general_operand" "ri,rm")))))
>  >           (clobber (reg:CC FLAGS_REG))]
>  >        "TARGET_64BIT && ix86_binary_operator_ok (MINUS, SImode, operands)"
>  >        "sbb{l}\t{%2, %k0|%k0, %2}"
>  >       [(set_attr "type" "alu")
>  >       (set_attr "pent_pair" "pu")
>  >       (set_attr "mode" "SI")])
>
> But this isn't a simple insn, it's a machine description pattern.
> These are described in Section 13, Machine Descriptions.
>
> Andrew.
>
>
Yes, this is a machine description pattern. In the genrecog.c file the
.md file is read and from each insn the RTL template is filled in the
RTX structure. So i want to know that how this insn ie the RTL teplate
from this insn will be filled in the RTX structure. I mean what part
of the template, each field of RTX structure will store? Could anybody
please tell me that?

Bharati.