llvm dev - Feb 2016 - Builder lld-x86_64-win7​ is back

On Tue, Feb 9, 2016 at 3:03 PM, Joerg Sonnenberger via llvm-commits <
llvm-commits at lists.llvm.org> wrote:
> On Tue, Feb 09, 2016 at 02:40:06PM -0800, Rui Ueyama via llvm-commits
> wrote:
> > Tried to fix the warning, and I'm not now sure if the warning
makes
> sense.
> > These "'~': zero extending '<smaller integer
type>' to 'int64_t' of
> greater
> > size" warning may be annoying as it is issued for code like
"int64_t x > > ~<some-int32_t-var>".
>
> This sounds like something were the semantic of the code is not
> obviously what was originally intended.
>
So you thought that was useful? Then why doesn't clang/gcc warn on that?

>
> Joerg
> _______________________________________________
> llvm-commits mailing list
> llvm-commits at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-commits
>
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On Tue, Feb 09, 2016 at 03:09:01PM -0800, Rui Ueyama
wrote:
> On Tue, Feb 9, 2016 at 3:03 PM, Joerg Sonnenberger via llvm-commits <
> llvm-commits at lists.llvm.org> wrote:
> 
> > On Tue, Feb 09, 2016 at 02:40:06PM -0800, Rui Ueyama via llvm-commits
> > wrote:
> > > Tried to fix the warning, and I'm not now sure if the warning
makes
> > sense.
> > > These "'~': zero extending '<smaller integer
type>' to 'int64_t' of
> > greater
> > > size" warning may be annoying as it is issued for code like
"int64_t x > > > ~<some-int32_t-var>".
> >
> > This sounds like something were the semantic of the code is not
> > obviously what was originally intended.
> >
> 
> So you thought that was useful? Then why doesn't clang/gcc warn on
that?
Good question :) I mean consider:

    int64_t x;
    ...
    x &= ~7;

was the intention here really to clear the upper half of x as well? Same
question for a variable instead of 7.

Joerg

On Tue, Feb 9, 2016 at 3:47 PM, Joerg Sonnenberger via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> On Tue, Feb 09, 2016 at 03:09:01PM -0800, Rui Ueyama wrote:
> > On Tue, Feb 9, 2016 at 3:03 PM, Joerg Sonnenberger via llvm-commits
<
> > llvm-commits at lists.llvm.org> wrote:
> >
> > > On Tue, Feb 09, 2016 at 02:40:06PM -0800, Rui Ueyama via
llvm-commits
> > > wrote:
> > > > Tried to fix the warning, and I'm not now sure if the
warning makes
> > > sense.
> > > > These "'~': zero extending '<smaller
integer type>' to 'int64_t' of
> > > greater
> > > > size" warning may be annoying as it is issued for code
like "int64_t
> x > > > > ~<some-int32_t-var>".
> > >
> > > This sounds like something were the semantic of the code is not
> > > obviously what was originally intended.
> > >
> >
> > So you thought that was useful? Then why doesn't clang/gcc warn on
that?
>
> Good question :) I mean consider:
>
>     int64_t x;
>     ...
>     x &= ~7;
>
> was the intention here really to clear the upper half of x as well? Same
> question for a variable instead of 7.
>
I understand the point. It also warned a case such that you have a function
f(uint64_t) and a variable x uint32_t and call f(~x). It may be hard to
identify that the upper 32 bits are filled with zeros from local context.

However, my question still stands. :)
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