Hi all,
I have used cbranchmode4 instruction to generate combined compare and
branch instruction.
(define_insn "cbranchmode4"
(set (pc) (if_then_else
(match_operator:CC 0 "comparison_operator"
[ (match_operand:SI 1 "register_operand" "r,r")
(match_operand:SI 2 "nonmemory_operand" "O,r")])
(label_ref (match_operand 3 "" ""))
(pc)))]
This pattern matches if the code is of the form
if ( h == 1)
p = 0;
if the code is of the form
if (h), if (h >= 0)
p = 0;
Then it matches the seperate compare and branch instructions and not
cbranch instruction.
Can anyone point out where i am going wrong?
Regards,
Rohit
On 06 Nov 2006 23:15:04 -0800, Ian Lance Taylor <[EMAIL PROTECTED]> wrote:
"Rohit Arul Raj" <[EMAIL PROTECTED]> writes:
> I am trying to combine the compare and branch instruction. But my
> instructions are not getting generated as my operands are not matched
> properly.
>
> Previously for individual compare instructions, i had
> operand 0 - Register operand
> operand 1 - Non memory operand.
>
> For branch instruction,
> operator 0 - compare operator
> operand 1 - label.
>
> So when i combined compare and branch, i just superimposed both
> statements with same conditions with
> operand 0 - Register operand
> operand 1 - Non memory operand
> operator 2 - comparison operator
> operand 3 - label.
>
> 1. Is it the right way to match operands and operators while combining
> instruction?
> 2. How to check where my instruction matching goes wrong?
When writing an MD file you have to think about what you generate
(insns/expanders with standard names) and what you recognize (insns).
You have to always generate something which you can recognize.
Anyhow, the easier way to generate a combined compare and branch
instruction is to use an insn or expander with the cbranchMM4 standard
name. See the documentation.
Ian
