Threads in the new ISO C Standard from 2011

Constant Propagation Example 3(3)
Preserving the data dependency means letting the hardware know
about them.
That can be done in different ways for different processors.
One way is to insert instructions so that there will be a chain of
dependences for the processor pipeline to see.
Compilers thus must preserve such dependences in the complete
program!
Writing optimizing compilers C all of a sudden became twice as
interesting.
There is, however, a very simple first version implementation: treat all
memory_order_consume as memory_order_acquire which
automatically will order the memory accesses.
Jonas Skeppstedt (js@cs.lth.se) Lecture 6 2013 44 / 70