[llvm-dev] 回复：RE: How to change IR type?

[Celine via llvm-dev]

Thank you very much for this information~




------------------ 原始邮件 ------------------
发件人: "Krzysztof Parzyszek"<kparzysz at quicinc.com>; 
发送时间: 2019年10月15日(星期二) 晚上8:34
收件人: "Celine"<595602881 at qq.com>; "llvm-dev"<llvm-dev at lists.llvm.org>; 
主题: RE: [llvm-dev]  How to change IR type?



       
In general you can use Value::mutateType to change the type of a value.  You can’t change the types arbitrarily though, I think that the operands to “add” still need to have the same type.
 
 
 
--  
 
Krzysztof Parzyszek  kparzysz at quicinc.com   AI tools development
 
 
    
From: llvm-dev <llvm-dev-bounces at lists.llvm.org> On Behalf Of Celine via llvm-dev
 Sent: Tuesday, October 15, 2019 5:25 AM
 To: llvm-dev <llvm-dev at lists.llvm.org>
 Subject: [EXT] [llvm-dev] How to change IR type?
 
 
 
 
  
hello,
 
  
 
 
  
I want to change the following IR:
 
  
  %2 = tail call i16 @llvm.nvvm.read.ptx.sreg.tid.x() #2
   %add = add i16 %mul6, %2
 
  
to 
 
   
  %2 = tail call i16v @llvm.nvvm.read.ptx.sreg.tid.x() #2
 (i16v)%add = add i16 %mul6, (i16v)%2     //Here keep %mul6 i16 as it is.
 
  
 
 
  
I'm not familar with LLVM IR API, it's not easy to get the type and change it right away. Seems need to create a new IR and replace the old one? 
 
  
But it's also hard to CreateCall() or CreateAdd(), hard to get the original IR's info to fill in those CreateXXX parameter. 
 
  
 
 
  
Any ideas or reference code?
 
  
How to learn LLVM IR API quickly?
 
  
 
 
  
--
 
  
Best Regards
 
  
Celine
 
  
 
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