On 2012/10/12 03:50, Eitan Adler wrote:
On 11 October 2012 07:44, Pawel Jakub Dawidek wrote:
On Tue, Oct 09, 2012 at 01:51:05PM -0400, Eitan Adler wrote:
On 9 October 2012 13:27, wrote:
The original behavior can be recovered by using inline assembly to
fetch the value from a register into a
On 11 October 2012 07:44, Pawel Jakub Dawidek wrote:
> On Tue, Oct 09, 2012 at 01:51:05PM -0400, Eitan Adler wrote:
>> On 9 October 2012 13:27, wrote:
>> > The original behavior can be recovered by using inline assembly to
>> > fetch the value from a register into a local C variable; this would
On 11.10.2012 19:23, Peter Wemm wrote:
> On Thu, Oct 11, 2012 at 6:14 AM, Andrey Chernov wrote:
>> On 11.10.2012 15:44, Pawel Jakub Dawidek wrote:
>>> On Tue, Oct 09, 2012 at 01:51:05PM -0400, Eitan Adler wrote:
On 9 October 2012 13:27, wrote:
> The original behavior can be recovered by
On Thu, Oct 11, 2012 at 6:14 AM, Andrey Chernov wrote:
> On 11.10.2012 15:44, Pawel Jakub Dawidek wrote:
>> On Tue, Oct 09, 2012 at 01:51:05PM -0400, Eitan Adler wrote:
>>> On 9 October 2012 13:27, wrote:
The original behavior can be recovered by using inline assembly to
fetch the valu
On 11.10.2012 15:44, Pawel Jakub Dawidek wrote:
> On Tue, Oct 09, 2012 at 01:51:05PM -0400, Eitan Adler wrote:
>> On 9 October 2012 13:27, wrote:
>>> The original behavior can be recovered by using inline assembly to
>>> fetch the value from a register into a local C variable; this would at
>>> l
On Tue, Oct 09, 2012 at 01:51:05PM -0400, Eitan Adler wrote:
> On 9 October 2012 13:27, wrote:
> > The original behavior can be recovered by using inline assembly to
> > fetch the value from a register into a local C variable; this would at
> > least not rely on undefined behavior. But I agree i
On Tue, Oct 09, 2012 at 06:06:55PM -0400, Eitan Adler wrote:
> On 9 October 2012 17:25, Steve Kargl
> wrote:
>
> ... yes, I was misreading the text.
>
> > Clang has no way of determining if 'a' is initialized or not.
> > If David is correct that 'junk' is optimized out by clang/llvm,
> > then i
On 9 October 2012 18:06, Eitan Adler wrote:
> On 9 October 2012 17:25, Steve Kargl
> wrote:
>
> ... yes, I was misreading the text.
>
>> Clang has no way of determining if 'a' is initialized or not.
>> If David is correct that 'junk' is optimized out by clang/llvm,
>> then it seems that clang vi
On 9 October 2012 17:25, Steve Kargl wrote:
... yes, I was misreading the text.
> Clang has no way of determining if 'a' is initialized or not.
> If David is correct that 'junk' is optimized out by clang/llvm,
> then it seems that clang violates footnote 116. Yes, I know
> it is non-normative t
On Tue, Oct 09, 2012 at 04:23:59PM -0400, Eitan Adler wrote:
> On 9 October 2012 14:24, Andrey Chernov wrote:
> > I don't have ISO9899 nearby, could you directly quote mentioned
> > sections, please?
>
> Accesses to volatile object (a) produce side effects (b) have
> implementation defined values
On 9 October 2012 14:24, Andrey Chernov wrote:
> I don't have ISO9899 nearby, could you directly quote mentioned
> sections, please?
Accesses to volatile object (a) produce side effects (b) have
implementation defined values.
A more careful re-reading of the relevant section leads me to believe
On 09.10.2012 21:47, Eitan Adler wrote:
> On 9 October 2012 12:33, Andrey Chernov wrote:
>> Do you check assembler output for _both_ cases?
>
> Yes.
...
> http://blog.eitanadler.com/2012/10/reduced-entropy-in-rand-and-random.html
At this URL I see only already known buggy assembler without 'vola
On 9 October 2012 13:16, David Chisnall wrote:
> On 9 Oct 2012, at 17:33, Andrey Chernov wrote:
>
>> Do you check assembler output for _both_ cases?
>> In my testing clang and gcc xor's 'junk' properly in case it have
>> 'volatile' keyword (as in srandomdev()) and elide it without 'volatile'.
>> I
On 9 October 2012 13:27, wrote:
> The original behavior can be recovered by using inline assembly to
> fetch the value from a register into a local C variable; this would at
> least not rely on undefined behavior. But I agree it's of dubious
> value anyways.
I proposed this (with a patch). We w
On 9 October 2012 12:33, Andrey Chernov wrote:
> Do you check assembler output for _both_ cases?
Yes.
> In my testing clang and gcc xor's 'junk' properly in case it have
> 'volatile' keyword (as in srandomdev()) and elide it without 'volatile'.
volatile is still undefined: see 5.1.2.2.3 and 6.7
On Tue, Oct 9, 2012 at 10:16 AM, David Chisnall wrote:
> On 9 Oct 2012, at 17:33, Andrey Chernov wrote:
>
>> Do you check assembler output for _both_ cases?
>> In my testing clang and gcc xor's 'junk' properly in case it have
>> 'volatile' keyword (as in srandomdev()) and elide it without 'volatil
On 9 Oct 2012, at 17:33, Andrey Chernov wrote:
> Do you check assembler output for _both_ cases?
> In my testing clang and gcc xor's 'junk' properly in case it have
> 'volatile' keyword (as in srandomdev()) and elide it without 'volatile'.
> IMHO this change should be backed out for srandomdev() a
Do you check assembler output for _both_ cases?
In my testing clang and gcc xor's 'junk' properly in case it have
'volatile' keyword (as in srandomdev()) and elide it without 'volatile'.
IMHO this change should be backed out for srandomdev() and adding
'volatile' for sranddev() instead.
On 09.10.2
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