[llvm-dev] New to LLVM. Need help generating assembly (original) (raw)

m m via llvm-dev llvm-dev at lists.llvm.org
Thu Dec 6 10:48:39 PST 2018

Swapping the order of SP and $amount in the pattern did not work. I checked the output of the compiler with the -print-after-all option and the instruction is present in the last IR dump.

I noticed that in GenAsmWriter.inc, there is this line of code in the case of my ADS instruction printOperand(MI, 0, O);

If I manually change it to printOperand(MI, 1, O);, then it fixes the problem.

How can I make tablegen generate a 1 as the 2nd argument of printOperand for this specific instruction?

From: daniel_l_sanders at apple.com <daniel_l_sanders at apple.com> on behalf of Daniel Sanders <daniel_l_sanders at apple.com> Sent: Thursday, December 6, 2018 9:31 AM To: tstellar at redhat.com Cc: m m; llvm-dev at lists.llvm.org Subject: Re: [llvm-dev] New to LLVM. Need help generating assembly

On Dec 5, 2018, at 22:15, Tom Stellard via llvm-dev <llvm-dev at lists.llvm.org<mailto:llvm-dev at lists.llvm.org>> wrote:

On 12/05/2018 07:22 PM, m m via llvm-dev wrote: Hi, I'm new to LLVM and need some help. I defined an instruction to increment the stack pointer by 'amount' (i.e. sp = sp + amount). During assembly generation, the string that gets emitted is "ADS $SP" rather than "ADS 10", for example, if I want to increment it by 10.

Can somebody show me what I'm doing wrong? Thanks.

def ADS: F_J<0b100001,(outs),(ins i32imm:$amount),"ADS amount",[(setSP,(addSP,i32imm:amount",[(set SP, (add SP, i32imm:amount",[(setSP,(addSP,i32imm:amount))] > {

   bits<10> amount;

   let Inst{9-0} = amount;
   let isReMaterializable = 1;
   let mayLoad = 0;
   let mayStore = 0;
   let Defs = [SP];
   let Uses = [SP];

}

What does the MCInst dump of this instruction look like? Have you looked at YourTargetGenAsmWriter.inc to see which print methods are being called for this instruction?

-Tom

It's also worth checking the output of the compiler with the -print-after-all option to see if your instruction is present in the last IR dump. It's possible that another instruction is being selected instead of this one.

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