On Fri, Aug 07, 2020 at 11:36:59PM +0200, Marc Glisse wrote:
> > > https://en.wikipedia.org/wiki/Extended_Euclidean_algorithm is the most
> > > common way to compute the modular multiplicative inverse of a number. For
> > > 3
> > > and 2^32, it could tell us that 2863311531*3-2*2^32=1, so modulo 2
On 07/08/20 21:57, Marc Glisse wrote:
On Fri, 7 Aug 2020, Joern Wolfgang Rennecke wrote:
However, there are cases were the second division will not be
possible without rest.
Consider : 7*X == 3
3/7 is 0 rest 3.
0x1 / 7 is 0x24924924 rest 4
Since 3 cannot be represented as an integer
On Fri, 7 Aug 2020, Jakub Jelinek wrote:
On Fri, Aug 07, 2020 at 10:57:54PM +0200, Marc Glisse wrote:
On Fri, 7 Aug 2020, Joern Wolfgang Rennecke wrote:
On 07/08/20 19:21, Marc Glisse wrote:
If we are going to handle the wrapping case, we shouldn't limit to
the non-wrapping meaning of mult
On Fri, Aug 07, 2020 at 10:57:54PM +0200, Marc Glisse wrote:
> On Fri, 7 Aug 2020, Joern Wolfgang Rennecke wrote:
>
> >
> > On 07/08/20 19:21, Marc Glisse wrote:
> > >
> > > If we are going to handle the wrapping case, we shouldn't limit to
> > > the non-wrapping meaning of multiplicity. 3*X==5
On Fri, 7 Aug 2020, Joern Wolfgang Rennecke wrote:
On 07/08/20 19:21, Marc Glisse wrote:
If we are going to handle the wrapping case, we shouldn't limit to the
non-wrapping meaning of multiplicity. 3*X==5 should become X==1431655767
(for a 32 bit type), etc.
Do we have an extended gcd som
On 07/08/20 19:21, Marc Glisse wrote:
If we are going to handle the wrapping case, we shouldn't limit to the
non-wrapping meaning of multiplicity. 3*X==5 should become
X==1431655767 (for a 32 bit type), etc.
Do we have an extended gcd somewhere in gcc, to help compute 1431655767?
I don't
On Fri, 7 Aug 2020, Joern Wolfgang Rennecke wrote:
this transformation is quite straightforward, without overflow, 3*X==15 is
the same as X==5 and 3*X==5 cannot happen.
Actually, with binary and decimal computers, this transformation (with
these specific numbers) is also valid for wrapping ov
this transformation is quite straightforward, without overflow, 3*X==15 is
the same as X==5 and 3*X==5 cannot happen.
Actually, with binary and decimal computers, this transformation (with these
specific numbers)
is also valid for wrapping overflow. More generally, it is valid for wrapping
ov
On Mon, 3 Aug 2020, Richard Biener wrote:
On Sat, Aug 1, 2020 at 9:29 AM Marc Glisse wrote:
Hello,
this transformation is quite straightforward, without overflow, 3*X==15 is
the same as X==5 and 3*X==5 cannot happen. Adding a single_use restriction
for the first case didn't seem necessary, a
On Sat, Aug 1, 2020 at 9:29 AM Marc Glisse wrote:
>
> Hello,
>
> this transformation is quite straightforward, without overflow, 3*X==15 is
> the same as X==5 and 3*X==5 cannot happen. Adding a single_use restriction
> for the first case didn't seem necessary, although of course it can
> slightly
Hello,
this transformation is quite straightforward, without overflow, 3*X==15 is
the same as X==5 and 3*X==5 cannot happen. Adding a single_use restriction
for the first case didn't seem necessary, although of course it can
slightly increase register pressure in some cases.
Bootstrap+regtes
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