[Bug tree-optimization/60206] IVOPT has no idea of inline asm

[wmi at google dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60206

--- Comment #4 from wmi at google dot com ---

> On Fri, 14 Feb 2014, pinskia at gcc dot gnu.org wrote:
> 
> > I think the real issue __FP_FRAC_SUB_4 needs to be fixed not to use inline-asm
> > but normal C code.  The normal C code should be able to produce as good as the
> > inline-asm code now too.
> 
> Does GCC do a good job of detecting add-with-carry and 
> subtract-with-borrow patterns (i.e. detecting the comparison that 
> corresponds to the carry flag and its use in a subsequent operation)?

I remember at least the expansion of builtin_strlen could generate
sub-with-borrow and it works well, so I think rtl passes could handle
add-with-carry/subtract-with-borrow.