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Re: rtx structure

On 11/2/06, Andrew Haley <> wrote:
Bharati Bhole writes:
 > On 11/2/06, Daniel Berlin <> 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.


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?


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