Why?

LLVM docs.txt

atomicrmw [volatile] <operation> <ty>* <pointer>, <ty> <value> [syncscope("<target-scope>")] <ordering>[, align <alignment>]  ; yields ty
<...>
"The instruction can take an optional align attribute. The alignment must be a power of two greater or equal to the size of the <value> type. If unspecified, the alignment is assumed to be equal to the size of the ‘<value>’ type. Note that this default alignment assumption is different from the alignment used for the load/store instructions when align isn’t specified."

output.txt

$ llc /home/david/src/java/qbicc-test-project/target/native/java/util/concurrent/atomic/AtomicInteger.ll
llc: error: llc: /home/david/src/java/qbicc-test-project/target/native/java/util/concurrent/atomic/AtomicInteger.ll:73:63: error: expected metadata after comma
  %L7 = atomicrmw add i32 addrspace(1)* %L6, i32 %p0 acq_rel, align 4, !dbg !15 ; AtomicInteger.java:239 bci@8
                                                              ^