[PATCH] Cleanup asm constraints in atomic operations

[John Baldwin]

alc@ brought to my attention a while back that while gcc allows one to use the 
'+' constraint modifier to collapse identical input and output operands that 
are in registers, it is only allowed for registers and not for memory 
operands.  The patch below removes uses of the '+' modifier in conjunction 
with memory operands in the atomic operations for alpha, amd64, i386, and 
powerpc.  Please test and let me know if there are any regressions.

-- 
John Baldwin <jhb at FreeBSD.org>  <><  http://www.FreeBSD.org/~jhb/
"Power Users Use the Power to Serve"  =  http://www.FreeBSD.org