On Tue, Aug 8, 2023 at 12:44 AM Richard Biener via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> On Tue, Aug 8, 2023 at 2:55 AM Andrew Pinski via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > This adds a simple match pattern for this case.
> > I noticed it a couple of different places.
> > One while I was looking at code generation of a parser and
> > also while I was looking at locations where bitwise_inverted_equal_p
> > should be used more.
> >
> > OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.
> >
> > PR tree-optimization/110937
> > PR tree-optimization/100798
> >
> > gcc/ChangeLog:
> >
> > * match.pd (`a ? ~b : b`): Handle this
> > case.
> >
> > gcc/testsuite/ChangeLog:
> >
> > * gcc.dg/tree-ssa/bool-14.c: New test.
> > * gcc.dg/tree-ssa/bool-15.c: New test.
> > * gcc.dg/tree-ssa/phi-opt-33.c: New test.
> > * gcc.dg/tree-ssa/20030709-2.c: Update testcase
> > so `a ? -1 : 0` is not used to hit the match
> > pattern.
> > ---
> > gcc/match.pd | 13 +++++++++++++
> > gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c | 5 +++--
> > gcc/testsuite/gcc.dg/tree-ssa/bool-14.c | 15 +++++++++++++++
> > gcc/testsuite/gcc.dg/tree-ssa/bool-15.c | 18 ++++++++++++++++++
> > gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c | 13 +++++++++++++
> > 5 files changed, 62 insertions(+), 2 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/bool-14.c
> > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/bool-15.c
> > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c
> >
> > diff --git a/gcc/match.pd b/gcc/match.pd
> > index 9b4819e5be7..f887c517c81 100644
> > --- a/gcc/match.pd
> > +++ b/gcc/match.pd
> > @@ -6460,6 +6460,19 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
> > (if (cmp == NE_EXPR)
> > { constant_boolean_node (true, type); })))))))
> >
> > +#if GIMPLE
> > +/* a?~t:t -> (-(a))^t */
> > +(simplify
> > + (cond @0 @1 @2)
> > + (if (bitwise_inverted_equal_p (@1, @2))
>
> I'm not sure if that can ever match a not INTEGRAL_TYPE_P
> but we can have vector typed @1 and @2 and then the
> TYPE_PRECISION ask below would be wrong. So can you
> add
>
> INTEGRAL_TYPE_P (type)
> && bitwise_in...
>
> if only for clarity?
>
> > + (with {
> > + auto prec = TYPE_PRECISION (type);
> > + auto unsign = TYPE_UNSIGNED (type);
> > + tree inttype = build_nonstandard_integer_type (prec, unsign);
> > + }
> > + (convert (bit_xor (negate (convert:inttype @0)) (convert:inttype
> > @2))))))
>
> so we don't get to know which of @1 or @2 is "simpler" (the not
> explicitely inverted
> operand), I suppose that's the disadvantage of using bitwise_inverted_equal_p.
> I'll note that if you make bitwise_inverted_equal_p a match you'd need a :c on
> the 'cond' but otherwise complexity would be the same as match patterns are
> not
> "inlined".
Right, The disadvantage is definitely not knowing which is "simpler".
And I found a testcase which shows that but I suspect we can fix that.
```
int f(int a, int t)
{
int t1 = ~t;
return (a=='s' ? t : t1);
}
```
Basically we are missing transforming:
~(-(cast)(cmp)) into -(cast)(cmp`)
Filed as PR 110949 .
>
> In any case, OK with the INTEGRAL_TYPE_P check.
Will update the patch and commit it after a bootstrap/test.
Thanks,
Andrew
>
> Thanks,
> Richard.
>
> > +#endif
> > +
> > /* Simplify pointer equality compares using PTA. */
> > (for neeq (ne eq)
> > (simplify
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c
> > b/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c
> > index 5009cd69cfe..78938f919d4 100644
> > --- a/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/20030709-2.c
> > @@ -29,15 +29,16 @@ union tree_node
> > };
> > int make_decl_rtl (tree, int);
> > void *
> > -get_alias_set (t)
> > +get_alias_set (t, t1)
> > tree t;
> > + void *t1;
> > {
> > long set;
> > if (t->decl.rtl)
> > return (t->decl.rtl->fld[1].rtmem
> > ? 0
> > : (((t->decl.rtl ? t->decl.rtl: (make_decl_rtl (t, 0),
> > t->decl.rtl)))->fld[1]).rtmem);
> > - return (void*)-1;
> > + return t1;
> > }
> >
> > /* There should be precisely one load of ->decl.rtl. If there is
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bool-14.c
> > b/gcc/testsuite/gcc.dg/tree-ssa/bool-14.c
> > new file mode 100644
> > index 00000000000..0149380a63b
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/bool-14.c
> > @@ -0,0 +1,15 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
> > +/* PR tree-optimization/110937 */
> > +
> > +_Bool f2(_Bool a, _Bool b)
> > +{
> > + if (a)
> > + return !b;
> > + return b;
> > +}
> > +
> > +/* We should be able to remove the conditional and convert it to an xor. */
> > +/* { dg-final { scan-tree-dump-not "gimple_cond " "optimized" } } */
> > +/* { dg-final { scan-tree-dump-not "gimple_phi " "optimized" } } */
> > +/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 1 "optimized" } } */
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/bool-15.c
> > b/gcc/testsuite/gcc.dg/tree-ssa/bool-15.c
> > new file mode 100644
> > index 00000000000..1f496663863
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/bool-15.c
> > @@ -0,0 +1,18 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
> > +/* PR tree-optimization/110937 */
> > +
> > +_Bool f2(int x, int y, int w, int z)
> > +{
> > + _Bool a = x == y;
> > + _Bool b = w == z;
> > + if (a)
> > + return !b;
> > + return b;
> > +}
> > +
> > +/* We should be able to remove the conditional and convert it to an xor. */
> > +/* { dg-final { scan-tree-dump-not "gimple_cond " "optimized" } } */
> > +/* { dg-final { scan-tree-dump-not "gimple_phi " "optimized" } } */
> > +/* { dg-final { scan-tree-dump-not "ne_expr, " "optimized" } } */
> > +/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 1 "optimized" } } */
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c
> > b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c
> > new file mode 100644
> > index 00000000000..b79fe44187a
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/phi-opt-33.c
> > @@ -0,0 +1,13 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-O2 -fdump-tree-optimized-raw" } */
> > +/* PR tree-optimization/100798 */
> > +
> > +int f(int a, int t)
> > +{
> > + return (a=='s' ? ~t : t);
> > +}
> > +
> > +/* This should be convert into t^-(a=='s'). */
> > +/* { dg-final { scan-tree-dump-times "bit_xor_expr, " 1 "optimized" } } */
> > +/* { dg-final { scan-tree-dump-times "negate_expr, " 1 "optimized" } } */
> > +/* { dg-final { scan-tree-dump-not "bit_not_expr, " "optimized" } } */
> > --
> > 2.31.1
> >
