subreg vs register_operand

subreg vs register_operand

[Pierre Mallard]

Hi ,
I've got a simple set of define_insn to match move
instruction :

(define_insn "movqi"
  [(set (match_operand:QI 0 "nonimmediate_operand"
"=r,m,r,r")
	(match_operand:QI 1 "general_operand"      
"r,r,m,i"))]
  "(register_operand (operands[0],QImode)
    || register_operand (operands[1], QImode))"
  "* return output_movqi (insn, operands, NULL);"
  [(set_attr "length" "1,5,5,1")
   (set_attr "cc" "none,none,none,none")
   (set_attr "type" "none,load,none,none")])
(define_insn "movhi"
  [(set (match_operand:HI 0 "nonimmediate_operand"
"=r,r,m,r,r")
        (match_operand:HI 1 "general_operand"      
"r,m,r,I,i"))]
  "(register_operand (operands[0],HImode)
    || register_operand (operands[1],HImode))"
  "* return output_movhi (insn, operands, NULL);"
  [(set_attr "length" "1,6,6,1,2")
   (set_attr "cc" "none,none,none,none,none")
   (set_attr "type" "none,load,none,none,none")])

(define_insn "movsi"
  [(set (match_operand:SI 0 "nonimmediate_operand"
"=r,r,m,r,r")
        (match_operand:SI 1 "general_operand"      
"r,m,r,I,i"))]
  "(register_operand (operands[0],SImode)
    || register_operand (operands[1],SImode))"
  "* return output_movsisf (insn, operands, NULL);"
  [(set_attr "length" "2,8,8,2,4")
   (set_attr "cc"   "none,none,none,none,none")
   (set_attr "type" "none,load,none,none,none")])

In order to optimize the jump delay slot I make some
define_split to reduce SI and HI move :

(define_split
  [(set (match_operand:HI 0 "register_operand" "=r")
        (match_operand:HI 1 "general_operand" "i"))]
  ""
   [(set (subreg:QI (match_dup 0) 0) (match_operand:QI
2 "general_operand" "i"))
   (set (subreg:QI (match_dup 0) 1) (match_operand:QI
3 "general_operand" "i"))]
  "{
  HOST_WIDE_INT low = INTVAL(operands[1])&0xfff;
  HOST_WIDE_INT high = (INTVAL(operands[1])&0xfff000)
>> 12;
  operands[2] = GEN_INT(low);
  operands[3] = GEN_INT(high);
  }")
(define_split
  [(set (match_operand:SI 0 "register_operand" "")
        (match_operand:SI 1 "register_operand" ""))]
  ""
   [(set (subreg:HI (match_dup 0) 0)
(subreg:HI(match_dup 1) 0))
   (set (subreg:HI (match_dup 0) 2) (subreg:HI
(match_dup 1) 2))]
  "")

(define_split
  [(set (match_operand:SI 0 "register_operand" "=r")
        (match_operand:SI 1 "general_operand" "i"))]
  ""
   [(set (subreg:HI (match_dup 0) 0) (match_operand:HI
2 "general_operand" "i"))
   (set (subreg:HI (match_dup 0) 2) (match_operand:HI
3 "general_operand" "i"))]
  "{
  HOST_WIDE_INT low =
CONST_DOUBLE_LOW(operands[1])&0xffffff;
  HOST_WIDE_INT high =
((CONST_DOUBLE_LOW(operands[1])&0xff000000) >>
24)|((CONST_DOUBLE_HIGH(operands[1])&0xffff) << 8);
  operands[2] = GEN_INT(low);
  operands[3] = GEN_INT(high);
  }")

When the compiler split a MOVSI(reg,immediate), into
an HI and then into a QI it just throw an error :
Unrecognizable insn:
(insn 357 190 358 (set (subreg:QI (subreg:HI (reg:SI
16 r16) 0) 0)
        (const_int 0 [0x0])) -1 (nil)
    (nil))

I'm wondering why this insn is not catch by
define_insn "movqi" as a simple (set (reg:QI would do?

Someone can help me?
Thanks, regards
Pierre

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Re: subreg vs register_operand

[Richard Henderson]

On Thu, Sep 12, 2002 at 10:09:56AM +0200, Pierre Mallard wrote:
> Unrecognizable insn:
> (insn 357 190 358 (set (subreg:QI (subreg:HI (reg:SI 16 r16) 0) 0)

Nested subregs are illegal.

This happened because you did this:

>    [(set (subreg:HI (match_dup 0) 0) ...

You should be using gen_lowpart instead of creating
subregs by yourself.


r~

Re: subreg vs register_operand

[Pierre Mallard]

Thanks for your answer.
This works well for the low_part of the reg but the
high_part seems to be working only when I split a HI
reg into 2 QI reg (wich has the size of
UNIT_PER_WORD).
But when I'm trying to split an SI reg into 2 HI regs,
gen_high_part generate an internal compiler error, due
to the test :
  if (GET_MODE_SIZE (mode) > UNITS_PER_WORD
      && GET_MODE_SIZE (mode) != GET_MODE_UNIT_SIZE
(GET_MODE (x)))
    abort ();

Is gen_high_part the right expression to generate an
HI register, highpart of an SI register, when the
WORD_SIZE is set on QI?

Pierre

ps : when u have in the assembler mnemonics to
different kind of register size (QI and HI) is it
better to define word as having the size of HI?
 --- Richard Henderson <rth@redhat.com> a écrit : > On
Thu, Sep 12, 2002 at 10:09:56AM +0200, Pierre
> Mallard wrote:
> > Unrecognizable insn:
> > (insn 357 190 358 (set (subreg:QI (subreg:HI
> (reg:SI 16 r16) 0) 0)
> 
> Nested subregs are illegal.
> 
> This happened because you did this:
> 
> >    [(set (subreg:HI (match_dup 0) 0) ...
> 
> You should be using gen_lowpart instead of creating
> subregs by yourself.
> 
> 
> r~ 

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