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Re: Question about Machine Description
Hi,
I want to change instruction blez to ble. ble compare two registers and jump
to the target address if the condition is true.
thanks in advance,
Ian Lance Taylor-3 wrote:
>
> yazdanbakhsh <amir.yazdanbakhsh@gmail.com> writes:
>
>> Please assume I'm working with the MIPS. There is a little difference
>> between the MIPS and what I'm actually working on it. How can I remove
>> immediate logical shift right/left from the compiler?
>> I mean If I want the programmer writes an immediate shift, It is compiled
>> to
>> the two instructions:
>>
>> sll %2,%2,5
>>
>> changed to:
>>
>> addi %3,%0,5
>> sllv %2,%2,%3
>
> Find the insn which generates sll. Change the operand constraints and
> predicates to reject an immediate operand.
>
> E.g., in mips.md this is:
>
> (define_insn "*<optab><mode>3"
> [(set (match_operand:GPR 0 "register_operand" "=d")
> (any_shift:GPR (match_operand:GPR 1 "register_operand" "d")
> (match_operand:SI 2 "arith_operand" "dI")))]
> "!TARGET_MIPS16"
> {
> if (CONST_INT_P (operands[2]))
> operands[2] = GEN_INT (INTVAL (operands[2])
> & (GET_MODE_BITSIZE (<MODE>mode) - 1));
>
> return "<d><insn>\t%0,%1,%2";
> }
> [(set_attr "type" "shift")
> (set_attr "mode" "<MODE>")])
>
>
> For operand 2, change the predicate to register_operand and remove the
> 'I' constraint.
>
> Ian
>
>
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