llvm dev - May 2010 - [LLVMdev] Can the structure, having few integers and 'opaque', be manipulated upon?

{ i32, i32, opaque }

When I try running through JIT the code, incrementing the field in such 
structure, I am getting an assert:
Assertion failed: (Ty->isSized() && "`!"), function
getAlignment, file
/tmp/llvm-build/2.7/llvm/lib/Target/TargetData.cpp, line 498.

I understand that C/C++ can't possibly produce such structure due to 
their language limitations. But llvm is supposed to be more generic. 
There should be no problem manipulating such structure, since opaque is 
only in the end.

llvm-2.7

Yuri