atomicrmw

Hi!
It is said in http://llvm.org/docs/LangRef.html#i_atomicrmw there is an
atomicrmw opcode.
But:
store i8 %2, i8* %tape1.sub
%3 = atomicrmw add i8* %tape1.sub, i8 1 acquire
fails with:
llc: test.bc:13:9: error: expected instruction opcode
%3 = atomicrmw add i8* %tape1.sub, i8 1 acquire

How can I do *ptr = *ptr + val with LLVM ?

What version of LLVM are you using? The documentation you're pointing
at reflects trunk (and the current 3.0 release candidate); the 2.9
docs for the equivalent construct are at
http://llvm.org/releases/2.9/docs/LangRef.html#int_atomic_load_add ,

-Eli