shifting among patterns

[Bill McEnaney]

Rajiv,

I'm sorry I don't know the answer to your question.  But thank you for
writing such readable code.

Cheers,
Bill
> 
> Hi all,
> 
> I am new to this porting gcc architecture field. I have a doubt.
> 
> What i was trying is, In "movdi" pattern for some pairs of constraints
like
> (r,r) or (m,r) i was letting movdi pattern to handle this while
working over
> 64bit data. But for other constraints pair like (r,i) or (r,m) i was
trying
> to make movsi handle this pair of constraints by diverting from movdi to
> movsi. I did it in this way:
> 
> (define_expand "movdi"
>   [(set (match_operand:DI 0 "general_operand" "")
> 	(match_operand:DI 1 "general_operand" ""))]
>   ""
>   "
>   	if(GET_CODE(operands[0])==MEM && GET_CODE(operands[1])!=REG)
> 
> 	{   
> 
> 		  if(can_create_pseudo_p())
> 
> 	   	  {
> 
> 			operands[1]=force_reg(DImode,operands[1]);
> 
> 	   	  }
> 
> 	}
>   "
> )
> (define_insn_and_split "*movdi"
>   [(set(match_operand: DI 0  "nonimmediate_operand" "=r,r,r,m")
> 
>         (match_operand:  DI  1   "general_operand"        "r,Di,m,r"))]
>         ""
> 	"*
> 	 switch (which_alternative)
> 	 {
> 	 case 0:  return \"#\";
> 	 case 1:  
> 	 case 2:  return divert_to_si(operands);
> 	 case 3:  return output_move_double (operands);	 
> 	 }"
> 	"reload_completed"
>       [(set (match_dup 0)(match_dup 1))
> 	 (set (match_dup 2)(match_dup 3))]
>         "{
> 	    operands[2] = gen_highpart (SImode, operands[0]);
> 	    operands[0] = gen_lowpart (SImode, operands[0]);
>  	    operands[3] = gen_highpart (SImode, operands[1]);
> 	    operands[1] = gen_lowpart (SImode, operands[1]);
> 	}"
> )
> 
> Here 'Di' is constraint for double integer range.
> 
> And 'divert_to_si' is function i have written in '.c' file:
> 
> void divert_to_si(rtx *operands)
> {
> 	printf("inside divert_to_si fxn\n");
> 	emit_insn(gen_movsi(operands[0],operands[1]));
> }
> 
> My doubts are:
> 
> 1.Can we do this type of diversion?
> 2.To me its giving 'segmentation fault' for simple 64bit assignment.
> 
> I am new, learning while practising. Please help me in this.
> 
> Rajiv.
> 
> 
> 
> 
> 
> 
> 
> 
> -- 
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http://old.nabble.com/shifting-among-patterns-tp27901006p27901006.html
> Sent from the gcc - Help mailing list archive at Nabble.com.
> 
> 

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