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Re: [match.pd] Fix for PR35691
On Tue, 8 Nov 2016, Prathamesh Kulkarni wrote:
> On 8 November 2016 at 13:23, Richard Biener <rguenther@suse.de> wrote:
> > On Mon, 7 Nov 2016, Prathamesh Kulkarni wrote:
> >
> >> On 7 November 2016 at 23:06, Prathamesh Kulkarni
> >> <prathamesh.kulkarni@linaro.org> wrote:
> >> > On 7 November 2016 at 15:43, Richard Biener <rguenther@suse.de> wrote:
> >> >> On Fri, 4 Nov 2016, Prathamesh Kulkarni wrote:
> >> >>
> >> >>> On 4 November 2016 at 13:41, Richard Biener <rguenther@suse.de> wrote:
> >> >>> > On Thu, 3 Nov 2016, Marc Glisse wrote:
> >> >>> >
> >> >>> >> On Thu, 3 Nov 2016, Richard Biener wrote:
> >> >>> >>
> >> >>> >> > > > > The transform would also work for vectors (element_precision for
> >> >>> >> > > > > the test but also a value-matching zero which should ensure the
> >> >>> >> > > > > same number of elements).
> >> >>> >> > > > Um sorry, I didn't get how to check vectors to be of equal length by a
> >> >>> >> > > > matching zero.
> >> >>> >> > > > Could you please elaborate on that ?
> >> >>> >> > >
> >> >>> >> > > He may have meant something like:
> >> >>> >> > >
> >> >>> >> > > (op (cmp @0 integer_zerop@2) (cmp @1 @2))
> >> >>> >> >
> >> >>> >> > I meant with one being @@2 to allow signed vs. Unsigned @0/@1 which was the
> >> >>> >> > point of the pattern.
> >> >>> >>
> >> >>> >> Oups, that's what I had written first, and then I somehow managed to confuse
> >> >>> >> myself enough to remove it so as to remove the call to types_match :-(
> >> >>> >>
> >> >>> >> > > So the last operand is checked with operand_equal_p instead of
> >> >>> >> > > integer_zerop. But the fact that we could compute bit_ior on the
> >> >>> >> > > comparison results should already imply that the number of elements is the
> >> >>> >> > > same.
> >> >>> >> >
> >> >>> >> > Though for equality compares we also allow scalar results IIRC.
> >> >>> >>
> >> >>> >> Oh, right, I keep forgetting that :-( And I have no idea how to generate one
> >> >>> >> for a testcase, at least until the GIMPLE FE lands...
> >> >>> >>
> >> >>> >> > > On platforms that have IOR on floats (at least x86 with SSE, maybe some
> >> >>> >> > > vector mode on s390?), it would be cool to do the same for floats (most
> >> >>> >> > > likely at the RTL level).
> >> >>> >> >
> >> >>> >> > On GIMPLE view-converts could come to the rescue here as well. Or we cab
> >> >>> >> > just allow bit-and/or on floats as much as we allow them on pointers.
> >> >>> >>
> >> >>> >> Would that generate sensible code on targets that do not have logic insns for
> >> >>> >> floats? Actually, even on x86_64 that generates inefficient code, so there
> >> >>> >> would be some work (for instance grep finds no gen_iordf3, only gen_iorv2df3).
> >> >>> >>
> >> >>> >> I am also a bit wary of doing those obfuscating optimizations too early...
> >> >>> >> a==0 is something that other optimizations might use. long
> >> >>> >> c=(long&)a|(long&)b; (double&)c==0; less so...
> >> >>> >>
> >> >>> >> (and I am assuming that signaling NaNs don't make the whole transformation
> >> >>> >> impossible, which might be wrong)
> >> >>> >
> >> >>> > Yeah. I also think it's not so much important - I just wanted to mention
> >> >>> > vectors...
> >> >>> >
> >> >>> > Btw, I still think we need a more sensible infrastructure for passes
> >> >>> > to gather, analyze and modify complex conditions. (I'm always pointing
> >> >>> > to tree-affine.c as an, albeit not very good, example for handling
> >> >>> > a similar problem)
> >> >>> Thanks for mentioning the value-matching capture @@, I wasn't aware of
> >> >>> this match.pd feature.
> >> >>> The current patch keeps it restricted to only bitwise operators on integers.
> >> >>> Bootstrap+test running on x86_64-unknown-linux-gnu.
> >> >>> OK to commit if passes ?
> >> >>
> >> >> +/* PR35691: Transform
> >> >> + (x == 0 & y == 0) -> (x | typeof(x)(y)) == 0.
> >> >> + (x != 0 | y != 0) -> (x | typeof(x)(y)) != 0. */
> >> >> +
> >> >>
> >> >> Please omit the vertical space
> >> >>
> >> >> +(for bitop (bit_and bit_ior)
> >> >> + cmp (eq ne)
> >> >> + (simplify
> >> >> + (bitop (cmp @0 integer_zerop) (cmp @1 integer_zerop))
> >> >>
> >> >> if you capture the first integer_zerop as @2 then you can re-use it...
> >> >>
> >> >> + (if (INTEGRAL_TYPE_P (TREE_TYPE (@0))
> >> >> + && INTEGRAL_TYPE_P (TREE_TYPE (@1))
> >> >> + && TYPE_PRECISION (TREE_TYPE (@0)) == TYPE_PRECISION (TREE_TYPE
> >> >> (@1)))
> >> >> + (cmp (bit_ior @0 (convert @1)) { build_zero_cst (TREE_TYPE (@0));
> >> >>
> >> >> ... here inplace of the { build_zero_cst ... }.
> >> >>
> >> >> Ok with that changes.
> >> > Thanks, committed the attached version as r241915.
> >> ugh, the svn commit message has:
> >>
> >> testsuite/
> >> * gcc.dg/pr35691-1.c: New test-case.
> >> * gcc.dg/pr35691-4.c: Likewise.
> >>
> >> pr35691-4.c was a typo, should be pr35691-2.c :/
> >> However testsuite/ChangeLog correctly has entry for pr35691-2.c
> >> Is it possible to edit the commit message for r241915 ?
> >> Sorry about this.
> >
> > No, just leave it as-is.
> Hi,
> Chritstophe reported to me that the commit caused test-cases
> pr35691-1.c and pr35691-2.c (which were added by the commit)
> to FAIL for cortex-a5:
> http://people.linaro.org/~christophe.lyon/cross-validation/gcc/trunk/241915/arm-none-linux-gnueabihf/diff-gcc-rh60-arm-none-linux-gnueabihf-arm-cortex-a5-vfpv3-d16-fp16.txt
>
> It seems truth_andif_expr is not simplified to bit_and_expr on
> cortex-a5 as for x86_64 (and other arm variants).
> The differences in dumps start from 004t.gimple for pr35691-1.c:
>
> x86_64 gimple dump:
> foo (int z0, unsigned int z1)
> {
> int D.1800;
> int t0;
> int t1;
> int t2;
>
> _1 = z0 == 0;
> t0 = (int) _1;
> _2 = z1 == 0;
> t1 = (int) _2;
> _3 = t0 != 0;
> _4 = t1 != 0;
> _5 = _3 & _4;
> t2 = (int) _5;
> D.1800 = t2;
> return D.1800;
> }
>
> cortex-a5 gimple dump:
> foo (int z0, unsigned int z1)
> {
> int iftmp.0;
> int D.4176;
> int t0;
> int t1;
> int t2;
>
> _1 = z0 == 0;
> t0 = (int) _1;
> _2 = z1 == 0;
> t1 = (int) _2;
> if (t0 != 0) goto <D.4174>; else goto <D.4172>;
> <D.4174>:
> if (t1 != 0) goto <D.4175>; else goto <D.4172>;
> <D.4175>:
> iftmp.0 = 1;
> goto <D.4173>;
> <D.4172>:
> iftmp.0 = 0;
> <D.4173>:
> t2 = iftmp.0;
> D.4176 = t2;
> return D.4176;
> }
>
> Since the pattern expects truth_andif_expr to be converted to bit_and_expr,
> it fails to match for cortex-a5.
> This seems to happen only for cortex-a5 (the other variants a9, a15,
> a57 are OK).
>
> Is my assumption that truth_andif_expr would be always converted to bit_and_expr
> for above case incorrect ?
Yes, it depends on LOGICAL_OP_SHORT_CIRCUIT.
Richard.
> Thanks,
> Prathamesh
> >
> > Richard.
> >
> >> Regards,
> >> Prathamesh
> >> >
> >> >>
> >> >> Richard.
> >>
> >>
> >
> > --
> > Richard Biener <rguenther@suse.de>
> > SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)
>
>
--
Richard Biener <rguenther@suse.de>
SUSE LINUX GmbH, GF: Felix Imendoerffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nuernberg)