[llvm-commits] [llvm] r42075 - in /llvm/trunk: lib/Transforms/Scalar/LICM.cpp test/Transforms/LICM/2007-09-17-PrompteValue.ll

[Dan Gohman]

> +      // If GEP base is NULL then the calculated address  used by Store or
> +      // Load instruction is invalid. Do not promote this value because
> +      // it may expose load and store instruction that are covered by
> +      // condition which may not yet folded.
> +      if (GetElementPtrInst *GEP = dyn_cast<GetElementPtrInst>(V))
> +        if (isa<ConstantPointerNull>(GEP->getOperand(0)))
> +          PointerOk = false;
> +

It looks like there's a larger problem here. The testcase's loop body
may never be executed, so it isn't safe for LICM to hoist/sink
anything out to an unguarded location, null pointer constants or
otherwise.

Dan

-- 
Dan Gohman, Cray Inc.