Re: CVS commit: src/lib/libc/arch/alpha/gen

[David Laight <david%l8s.co.uk@localhost>]

On Wed, Mar 21, 2012 at 11:57:25PM +0100, Nicolas Joly wrote:
> On Wed, Mar 21, 2012 at 10:42:58PM +0200, Alan Barrett wrote:
> > On Wed, 21 Mar 2012, Havard Eidnes wrote:
> > >Modified Files:
> > >   src/lib/libc/arch/alpha/gen: fpgetround.c fpsetround.c
> > >
> > >Log Message:
> > >Add some casts to get rid of "bitwise op on signed value is non-portable"
> > >warning from lint.
> > 
> > I see no bitwise ops on signed values here.
> > 
> > >-  return ((fpcrval.u64 >> 58) & 0x3);
> > >+  return ((fp_rnd)(fpcrval.u64 >> 58) & 0x3);
> > 
> > fpcrval.u64 is uint64_t.  After the "integer promotions",
> > it's still uint64_t (unless that's smaller than int, which is not 
> > the case for any existing NetBSD port).  After >>58, it's still 
> > uint64_t.  0x3 is a signed int, but the "usual arithmetic conversions"
> > should convert it to uint64_t.
> 
> The commit message reference the wrong lint warning.
> 
> /local/src/NetBSD/src/lib/libc/arch/alpha/gen/fpgetround.c(61): warning: 
> conversion from 'unsigned long' to 'enum <unnamed>' may lose accuracy [132]
> /local/src/NetBSD/src/lib/libc/arch/alpha/gen/fpsetround.c(61): warning: 
> conversion from 'unsigned long' to 'enum <unnamed>' may lose accuracy [132]

Which is bogus because of the '& 3' which brings the value inside valid
range.

The cast is really in the wrong place as well.

I am 100% against adding casts of numeric values to appease a tool that
isn't tracking the domains of the expressions.

        David

-- 
David Laight: david%l8s.co.uk@localhost