On Sun, 30 Jun 2013, Shiva Chen wrote: > But how the target generate abs instruction if the target abs have > saturation behavior ? > We couldn't use abssi2 naming pattern and ss_abssi2 naming pattern > doesn't exist.
If you want to use a saturating abs instruction for C code that exhibits undefined behavior in cases where the instruction saturates, you need to add support for ss_abssi2 patterns and teach the GIMPLE-to-RTL conversion to use such patterns as appropriate (in the absence of -fwrapv/-ftrapv, of course). -- Joseph S. Myers jos...@codesourcery.com
