[gomp4] Worker reduction builtin

[Nathan Sidwell]

I've committed this to gomp4  branch.  It creates a new builtin to be used for 
worker-level reductions that Cesar is working on.  When the builtin is expanded 
it allocates a slot in a new .shared array to hold the reduction variable.  This 
array is reused for reductions on different loops.

I also realized the lockk and unlock expanders needed to emit memory barriers to 
that writes made by one  thread in the protected region could be seen by other 
threads in the region.

nathan
-------------- next part --------------
A non-text attachment was scrubbed...
Name: gomp4-wrd.patch
Type: text/x-patch
Size: 13972 bytes
Desc: not available
URL: <http://gcc.gnu.org/pipermail/gcc-patches/attachments/20150804/3375c645/attachment.bin>