In article <[EMAIL PROTECTED]>,
Jeremy Higdon <[EMAIL PROTECTED]> wrote:
>
>In my case, it is simple "long long" arithmetic. Shifts, ANDs, ORs,
>comparisons, etc. Not even any addition (which should be pretty efficient
>with the HW carry bit on X86). I don't know why:
Oh, I agree. In your cas
So I understand the point about filesystems and values that always happen
to be a power of two where the compiler can't know that.
However:
> From: [EMAIL PROTECTED] (Linus Torvalds)
>
> >So what we've said is: 64 bit is okay, except in a switch statement,
> >or other random expressions that mi
In article <[EMAIL PROTECTED]>,
Jeremy Higdon <[EMAIL PROTECTED]> wrote:
>> - Linux developers often do horribly stupid things, and use 64-bit
>>division etc instead of using a simple shift. Again, not linking
>>against libgcc finds those things early rather than late, because the
>>h
[Jeremy Higdon]
> Is there a little FAQ of C constructions you should not use if you
> are writing kernel code? It took a little doing to figure out that
> it was the switch that was causing trouble and not the shifts and
> arithmetic operations, and I'd like to avoid that in the future :-).
He
[Cahalan]
> Well, what do you care about most? The problem can be solved in
> other, more disturbing ways. :-) For example, gcc's computed goto.
[code snipped]
You are sick. (:
Peter
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Jeremy Higdon writes:
> In reality, the switch does a 60 bit shift right, so I can cast to a
> uint, which is the right thing to do on old architectures :-), solving
> the problem. I had originally thought that the problem was in all the
> masks, shifts, and compares, but they are all inlined.
On Sep 19, 8:39am, Richard Henderson wrote:
>
> On Tue, Sep 19, 2000 at 12:22:41PM +0200, Andreas Schwab wrote:
> > IMHO it's a bug in gcc that it does not inline the comparison inside the
> > switch expression, since it already does it in all other places. Perhaps
> > some problem with the pat
> - Linux developers often do horribly stupid things, and use 64-bit
>division etc instead of using a simple shift. Again, not linking
>against libgcc finds those things early rather than late, because the
>horribly stupid things end up requireing libgcc support.
I would have thought
Linus Torvalds wrote:
>
> I'd love to link against libgcc, but for the fact that
>
> - gcc developers have sometimes done horribly stupid things, and NOT
>linking against libgcc has been an excellent way of not getting
>bitten by it. Things like the exception handling etc, where not
>
In article <[EMAIL PROTECTED]>,
Richard Henderson <[EMAIL PROTECTED]> wrote:
>On Tue, Sep 19, 2000 at 12:22:41PM +0200, Andreas Schwab wrote:
>> IMHO it's a bug in gcc that it does not inline the comparison inside the
>> switch expression, since it already does it in all other places. Perhaps
>>
On Tue, Sep 19, 2000 at 12:22:41PM +0200, Andreas Schwab wrote:
> IMHO it's a bug in gcc that it does not inline the comparison inside the
> switch expression, since it already does it in all other places. Perhaps
> some problem with the patterns in the machine description.
Perhaps, but without
On Sep 19, 1:08pm, Matti Aarnio wrote:
>
> On Tue, Sep 19, 2000 at 02:58:01AM -0700, Jeremy Higdon wrote:
> > Hello,
> >
> > I'm using a 64 bit variable in a switch statement. Gcc is generating code
> > which make calls to __ucmpdi2, a function defined in libgcc. I figured
> > out that it was
Matti Aarnio <[EMAIL PROTECTED]> writes:
|> On Tue, Sep 19, 2000 at 02:58:01AM -0700, Jeremy Higdon wrote:
|> > Hello,
|> >
|> > I'm using a 64 bit variable in a switch statement. Gcc is generating code
|> > which make calls to __ucmpdi2, a function defined in libgcc. I figured
|> > out that i
On Tue, Sep 19, 2000 at 02:58:01AM -0700, Jeremy Higdon wrote:
> Hello,
>
> I'm using a 64 bit variable in a switch statement. Gcc is generating code
> which make calls to __ucmpdi2, a function defined in libgcc. I figured
> out that it was the switch statement from examining the generated code
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