cast instruction

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1

I need to create a cast instruction that casts an sbyte* to another pointer type. Previously I was using the CastInst::createInferredCast() function to do that; however, that function has been removed. Which of the create() functions from CastInst should I use to do that? It seems like the obdvious answer should be createPointerCast(). However, the documentation for createPointerCast says, "Create a BitCast or a PtrToInt cast instruction," and I'm not wanting to cast a pointer to an int.

Thanks,
Ryan

2

I need to create a cast instruction that casts an sbyte* to another
pointer type. Previously I was using the CastInst::createInferredCast()
function to do that; however, that function has been removed. Which of
the create() functions from CastInst should I use to do that? It seems
like the obdvious answer should be createPointerCast(). However, the
documentation for createPointerCast says, "Create a BitCast or a
PtrToInt cast instruction," and I'm not wanting to cast a pointer to an int.

Pointer to pointer cast is always a bit cast so just use "new
BitCast(...)"

Reid.

3

Pointer to pointer casts use the 'bitcast' instruction, because the src/dest are required to be the same size.

-Chris

4

Ryan M. Lefever wrote:

I need to create a cast instruction that casts an sbyte* to another
pointer type.

A pointer to pointer cast is a bitcast.

  Previously I was using the CastInst::createInferredCast()

function to do that; however, that function has been removed. Which of
the create() functions from CastInst should I use to do that?

new BitCastInst(SourcePtr, DestTy, InstToInsertBefore);

  It seems

like the obdvious answer should be createPointerCast(). However, the
documentation for createPointerCast says, "Create a BitCast or a
PtrToInt cast instruction," and I'm not wanting to cast a pointer to an int.

createPointerCast is for cases when the pass doesn't know in advance
(statically) whether the destination type is pointer or int. In your
case, you know that the result is a pointer, so you can use the direct
constructor.

Nick Lewycky