llvm dev - Feb 2011 - [LLVMdev] How to replace a global variable to one with a different type?

I'm experimenting with "replaceAllUsesWith" and I see that it
requires that
the replacement be the same type.

Here's what I am trying to do: Say I have a global variable A whose type is
[10 x Foo]. The only references to A are via GEPs which get a pointer to the
first element: GEP(A, 0, 0), so in other words no user of A knows the length
of the array from the type.

Now I want to replace A with A', which is exactly the same except that it
has a different array length. I want to remove all references to the
original A. I can't use replaceAllUsesWith, because A and A' have
different
types.

-- 
-- Talin
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Hi Talin,
> I'm experimenting with "replaceAllUsesWith" and I see that it
requires that the
> replacement be the same type.
>
> Here's what I am trying to do: Say I have a global variable A whose
type is [10
> x Foo]. The only references to A are via GEPs which get a pointer to the
first
> element: GEP(A, 0, 0), so in other words no user of A knows the length of
the
> array from the type.
>
> Now I want to replace A with A', which is exactly the same except that
it has a
> different array length. I want to remove all references to the original A.
I
> can't use replaceAllUsesWith, because A and A' have different
types.
first generate a (constexpr) bitcast of A' to [10 x Foo]*, then do RAUW of A
with the bitcast.

Ciao, Duncan.