RFH: optabs code in the java front end

Sat Sep 11 20:21:00 GMT 2010

On 2010年9月11日, 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