[LLVMdev] Re: LLVM Compiler Infrastructure Tutorial

[Chris Lattner]

I agree with everything Vikram said, just one clarification:

On Thu, 21 Oct 2004, Vikram S. Adve wrote:
> >    In addition, in hardware description, there are lots of bit-vector
> > manipulations (e.g., bit extraction,
> > concatenatoin ...), which are not represented  in LLVM. We are
> > thinking about to add some intrinsic
> >  functions to LLVM, so that the original instruction set can be
> > untouched.
>
> That makes sense if you don't want to apply standard LLVM passes (e.g.,
> ADCE or LICM or PRE) to these operations.  If you do want to apply
> these passes, they would need to be instructions, not intrinsics.

This actually isn't the case.  If you mark the function as not
reading/writing memory (in the BasicAA pass), LICM and ADCE will operate
on calls to it.

-Chris

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