[LLVMdev] optimizing access to global

[Jochen Wilhelmy]

Hi!

I'd like to optimize access to a global (write after read), but I didn't get
it to work. I used:

passManager.add(llvm::createGlobalsModRefPass());
passManager.add(llvm::createGVNPass());

Are these passes correct to do it?

And my global is
@global = internal global %0, align 16

I have for example
int a = global.a.b[0];
global.a.b[0] = a; // this should be removed

Does anybody have a hint? It's still llvm 2.8
Maybe the array access is the cause but all indexes are constant.

-Jochen