RFH: optabs code in the java front end

[Joseph S. Myers]

On Sat, 11 Sep 2010, Andrew Haley wrote:

> The test tells us whether the back-end has atomic builtins.  If it doesn't
> then we generate calls to the libgcj back end.  I really don't want gcj
> to generate calls to nonexistent __compare_and_swap_4 or somesuch.

Maybe not to nonexistent functions, but if the functions exist - say the 
kernel-assisted libgcc functions used on Linux on SH, PA and older ARM 
processors - then certainly they should be used.  So optabs are hardly the 
right thing to check; if you need to know whether this functionality is 
supported, you need a hook that will say whether there is a library 
fallback when code for __sync_* isn't generated inline.

-- 
Joseph S. Myers
joseph@codesourcery.com