[llvm-commits] [llvm] r51134 - in /llvm/trunk: lib/Transforms/Scalar/InstructionCombining.cpp test/Transforms/InstCombine/2003-11-13-ConstExprCastCall.ll test/Transforms/InstCombine/fp-ret-bitcast.ll

[Duncan Sands]

Hi,

> > in your example you can see the function definition (and not just
> > a declaration), so doing the transform only when you have the
> > declaration of the callee to hand would be ok for this example.
> 
> Ah right, good call.  For declarations, I think the only cases that  
> matter are things like simplifylibcalls, when the libcall didn't have  
> the right prototype.  I'm not sure how much this matters.

maybe those would be cleaned by my globalopt transform :)

> > PS: I just chucked some code into GlobalOpt that teaches it to change
> > the type of a declaration if the only use is a bitcast to a function
> > type.  It seems to work!  This transforms the objc testcase to:
> 
> The problem is that this objc function can return float, double, and  
> long double depend on the callee :)

If it is called in several different ways in the same module then indeed
there's not much you can do.  Still, I can't help feeling this transform
is useful since I can imagine that quite often people have code in which
some bogus declaration is used but each call calls it in the "correct" way.

Ciao,

Duncan.