2012-10-01 Andrew MacLeod <amacleod@redhat.com>
PR target/54087
* optabs.c (expand_atomic_fetch_op_no_fallback): New. Factored code
from expand_atomic_fetch_op.
(expand_atomic_fetch_op): Try atomic_{add|sub} operations in terms of
the other one if direct opcode fails.
* testsuite/gcc.dg/pr54087.c: New testcase for atomic_sub ->
atomic_add when atomic_sub fails.
From-SVN: r191929
