[LLVMdev] The question of sext instruction implementation

Michael.Kang blackfin.kang at gmail.com
Tue Jul 13 04:20:27 PDT 2010

I saw the description in llvm documenattion for sext is as the following :

-- sext (CST to TYPE)
    Sign extend a constant to another type. The bit size of CST must
be smaller or equal to the bit size of TYPE. Both types must be

But in the code of llvm-2.6, the judge condition just allow smaller to
the bit size of TYPE as the following :

  case Instruction::SExt:
    return SrcTy->isIntOrIntVector() &&
           DstTy->isIntOrIntVector()&& SrcBitSize < DstBitSize;

So I feel confused the difference about the documentation and implementation.


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