[LLVMdev] How to make correct pattern for instruction?

[Carlos Almeida Jr.]

Hi Johnny,

Thank you for your help. I guess the pseudo instruction does not interfere in
the generated assembly code.
I'll check the file that describes the registers and I hope understand why
the assembly code is printed wrong (now is printed things like add r1, r0,
-40).

Cheers,
Carlos

Carlos Almeida Jr

On Thu, Nov 27, 2014 at 7:56 AM, Johnny Val <johnnydval at gmail.com> wrote:

> Hi Carlos,
>
> LLVM will do this automatically for you! There is no need for a pseudo
> instruction in this case. As long as you have a way of adding two i32s (or
> any other type) using registers then LLVM will automatically do what you
> described when immediates are involved.
>
> Cheers,
>
> Johnny
>
> On Wed, Nov 26, 2014 at 11:50 PM, Carlos Almeida Jr. <almeidajr at gmail.com>
> wrote:
>
>> Hi,
>>
>> I'm a beginner user using LLVM, and I'm trying to create a new backend
>> using CPU0 Tutorial as reference.
>> I have two instructions for add: add and addi (this is a pseudo
>> instruction, but imediate operations is not available in architecture).
>> That is my idea: When the LLVM instruction selection find addi r3 = r2 +
>> value
>>
>> must convert to this:
>>
>> - load r1, value
>> - add r3 = r2 + r1
>>
>> In archInstrInfo.td I declared the instructions of the architecture, but
>> I dont know how to "split" addi instruction. I tryed understand the LLVM
>> and CPU0 documentation for solve this but I not found anything. :(
>>
>> Could anyone help me?
>>
>> Thanks
>> Carlos
>>
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>>
>
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