On 09/03/2015 01:14 PM, Richard Sandiford wrote:
If the (and ...) form is a better canonical form (IMO yes) then
I think it would be better to make it the canonical form across
the baord and update the existing ports to use it. The criteria
could be something like no unjustifiable differences i
On Thu, Sep 03, 2015 at 07:53:12PM +0100, Wilco Dijkstra wrote:
> > > >>You will end up with a *lot* of target hooks like this. It will also
> > > >>make testing harder (less coverage). I am not sure that is a good idea.
> > > >
> > > >We certainly need a lot more target hooks in general so GCC c
Jeff Law writes:
> On 09/03/2015 12:53 PM, Wilco Dijkstra wrote:
>>> Segher Boessenkool wrote:
>>> On Thu, Sep 03, 2015 at 10:09:36AM -0600, Jeff Law wrote:
>> You will end up with a *lot* of target hooks like this. It will also
>> make testing harder (less coverage). I am not sure that
On Thu, Sep 03, 2015 at 12:42:30PM -0600, Jeff Law wrote:
> Note huge parts of combine are structured around the needs of processors
> from the late 80s and early 90s. The canonical forms selected for those
> processors may not be optimal for today's processors.
Or, more precisely, for the back
On 09/03/2015 12:53 PM, Wilco Dijkstra wrote:
Segher Boessenkool wrote:
On Thu, Sep 03, 2015 at 10:09:36AM -0600, Jeff Law wrote:
You will end up with a *lot* of target hooks like this. It will also
make testing harder (less coverage). I am not sure that is a good idea.
We certainly need a l
> Segher Boessenkool wrote:
> On Thu, Sep 03, 2015 at 10:09:36AM -0600, Jeff Law wrote:
> > >>You will end up with a *lot* of target hooks like this. It will also
> > >>make testing harder (less coverage). I am not sure that is a good idea.
> > >
> > >We certainly need a lot more target hooks in
On 09/03/2015 10:18 AM, Segher Boessenkool wrote:
But there are more efficient ways to emit single bit and masks tests that apply
to most CPUs rather than doing something specific that works for just one target
only. For example single bit test is a simple shift into carry flag or into the
sign
> Oleg Endo wrote:
> On 04 Sep 2015, at 01:54, Segher Boessenkool
> wrote:
>
> > On Thu, Sep 03, 2015 at 05:25:43PM +0100, Kyrill Tkachov wrote:
> >>> void g(void);
> >>> void f(int *x) { if (*x & 2) g(); }
> >
> >> A testcase I was looking at is:
> >> int
> >> foo (int a)
> >> {
> >> return (a
On 04 Sep 2015, at 01:54, Segher Boessenkool wrote:
> On Thu, Sep 03, 2015 at 05:25:43PM +0100, Kyrill Tkachov wrote:
>>> void g(void);
>>> void f(int *x) { if (*x & 2) g(); }
>
>> A testcase I was looking at is:
>> int
>> foo (int a)
>> {
>> return (a & 7) != 0;
>> }
>>
>> For me this genera
On Thu, Sep 03, 2015 at 05:25:43PM +0100, Kyrill Tkachov wrote:
> >void g(void);
> >void f(int *x) { if (*x & 2) g(); }
> A testcase I was looking at is:
> int
> foo (int a)
> {
> return (a & 7) != 0;
> }
>
> For me this generates:
> and w0, w0, 7
> cmp w0, wzr
>
> Kyrill Tkachov wrote:
> A testcase I was looking at is:
> int
> foo (int a)
> {
>return (a & 7) != 0;
> }
>
> For me this generates:
> and w0, w0, 7
> cmp w0, wzr
> csetw0, ne
> ret
>
> when it could be:
> tst w0, 7
> cs
On Thu, Sep 03, 2015 at 10:09:36AM -0600, Jeff Law wrote:
> >>You will end up with a *lot* of target hooks like this. It will also
> >>make testing harder (less coverage). I am not sure that is a good idea.
> >
> >We certainly need a lot more target hooks in general so GCC can do the
> >right th
On 03/09/15 17:18, Segher Boessenkool wrote:
On Thu, Sep 03, 2015 at 03:59:00PM +0100, Wilco Dijkstra wrote:
However there are 2 issues with this, one is the spurious subreg,
Combine didn't make that up out of thin air; something already used
DImode here. It could simplify it to SImode in thi
On Thu, Sep 03, 2015 at 03:59:00PM +0100, Wilco Dijkstra wrote:
> > > However there are 2 issues with this, one is the spurious subreg,
> >
> > Combine didn't make that up out of thin air; something already used
> > DImode here. It could simplify it to SImode in this case, that is
> > true, don't
On 09/03/2015 08:59 AM, Wilco Dijkstra wrote:
Segher Boessenkool wrote:
On Thu, Sep 03, 2015 at 12:43:34PM +0100, Wilco Dijkstra wrote:
Combine canonicalizes certain AND masks in a comparison with zero into extracts
of the
widest
register type. During matching these are expanded into a very i
On 09/03/2015 07:18 AM, Segher Boessenkool wrote:
On Thu, Sep 03, 2015 at 12:43:34PM +0100, Wilco Dijkstra wrote:
Combine canonicalizes certain AND masks in a comparison with zero into extracts
of the
widest
register type. During matching these are expanded into a very inefficient
sequence t
On 09/02/2015 03:00 PM, Segher Boessenkool wrote:
On Wed, Sep 02, 2015 at 01:59:58PM -0600, Jeff Law wrote:
(set (reg:CC 66 cc)
(compare:CC (and:DI (lshiftrt:DI (subreg:DI (reg/v:SI 76 [ xD.2641 ])
0)
(const_int 1 [0x1]))
(const_int 1 [0x1]))
(con
On Thu, Sep 3, 2015 at 10:59 PM, Wilco Dijkstra wrote:
>> Segher Boessenkool wrote:
>> On Thu, Sep 03, 2015 at 12:43:34PM +0100, Wilco Dijkstra wrote:
>> > > > Combine canonicalizes certain AND masks in a comparison with zero into
>> > > > extracts of the
>> > > widest
>> > > > register type. Dur
> Segher Boessenkool wrote:
> On Thu, Sep 03, 2015 at 12:43:34PM +0100, Wilco Dijkstra wrote:
> > > > Combine canonicalizes certain AND masks in a comparison with zero into
> > > > extracts of the
> > > widest
> > > > register type. During matching these are expanded into a very
> > > > inefficie
On Thu, Sep 03, 2015 at 12:43:34PM +0100, Wilco Dijkstra wrote:
> > > Combine canonicalizes certain AND masks in a comparison with zero into
> > > extracts of the
> > widest
> > > register type. During matching these are expanded into a very inefficient
> > > sequence that
> > fails to
> > > matc
> Segher Boessenkool wrote:
> Hi Wilco,
>
> On Wed, Sep 02, 2015 at 06:09:24PM +0100, Wilco Dijkstra wrote:
> > Combine canonicalizes certain AND masks in a comparison with zero into
> > extracts of the
> widest
> > register type. During matching these are expanded into a very inefficient
> > se
On Wed, Sep 02, 2015 at 01:59:58PM -0600, Jeff Law wrote:
> >(set (reg:CC 66 cc)
> > (compare:CC (and:DI (lshiftrt:DI (subreg:DI (reg/v:SI 76 [ xD.2641 ])
> > 0)
> > (const_int 1 [0x1]))
> > (const_int 1 [0x1]))
> > (const_int 0 [0])))
> Yea, this is an
On 09/02/2015 11:09 AM, Wilco Dijkstra wrote:
Hi,
Combine canonicalizes certain AND masks in a comparison with zero into extracts
of the widest
register type. During matching these are expanded into a very inefficient
sequence that fails to
match. For example (x & 2) == 0 is matched in combine
Hi Wilco,
On Wed, Sep 02, 2015 at 06:09:24PM +0100, Wilco Dijkstra wrote:
> Combine canonicalizes certain AND masks in a comparison with zero into
> extracts of the widest
> register type. During matching these are expanded into a very inefficient
> sequence that fails to
> match. For example (x
Hi,
Combine canonicalizes certain AND masks in a comparison with zero into extracts
of the widest
register type. During matching these are expanded into a very inefficient
sequence that fails to
match. For example (x & 2) == 0 is matched in combine like this:
Failed to match this instruction:
(
25 matches
Mail list logo
