Handle EQ_EXPR relation for operator_lshift.
Commit Message
Knowing that X << X is non-zero means X is also non-zero. This patch
teaches this this to range-ops.
As usual, the big twiddling experts could come up with all sorts of
fancy enhancements in this area, and we welcome all patches :).
I will push this pending tests.
gcc/ChangeLog:
PR tree-optimization/102546
* range-op.cc (operator_lshift::op1_range): Handle EQ_EXPR
relation.
---
gcc/range-op.cc | 19 ++++++++++++++++---
gcc/testsuite/gcc.dg/tree-ssa/pr102546.c | 23 +++++++++++++++++++++++
2 files changed, 39 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr102546.c
Comments
Well, after talking with Andrew it seems that X << Y being non-zero
also implies X is non-zero. So we don't even need relationals here.
So, I leave gori relationals in his capable hands, while I test this
much simpler patch which fixes the PR with no additional
infrastructure ;-).
Will push pending tests.
Aldy
On Fri, Oct 1, 2021 at 2:43 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>
> Knowing that X << X is non-zero means X is also non-zero. This patch
> teaches this this to range-ops.
>
> As usual, the big twiddling experts could come up with all sorts of
> fancy enhancements in this area, and we welcome all patches :).
>
> I will push this pending tests.
>
> gcc/ChangeLog:
>
> PR tree-optimization/102546
> * range-op.cc (operator_lshift::op1_range): Handle EQ_EXPR
> relation.
> ---
> gcc/range-op.cc | 19 ++++++++++++++++---
> gcc/testsuite/gcc.dg/tree-ssa/pr102546.c | 23 +++++++++++++++++++++++
> 2 files changed, 39 insertions(+), 3 deletions(-)
> create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr102546.c
>
> diff --git a/gcc/range-op.cc b/gcc/range-op.cc
> index 5e37133026d..53f3be4266e 100644
> --- a/gcc/range-op.cc
> +++ b/gcc/range-op.cc
> @@ -2075,9 +2075,14 @@ operator_lshift::op1_range (irange &r,
> tree type,
> const irange &lhs,
> const irange &op2,
> - relation_kind rel ATTRIBUTE_UNUSED) const
> + relation_kind rel) const
> {
> tree shift_amount;
> + int_range<2> adjust (type);
> +
> + if (rel == EQ_EXPR && !lhs.contains_p (build_zero_cst (type)))
> + adjust.set_nonzero (type);
> +
> if (op2.singleton_p (&shift_amount))
> {
> wide_int shift = wi::to_wide (shift_amount);
> @@ -2086,10 +2091,11 @@ operator_lshift::op1_range (irange &r,
> if (wi::ge_p (shift, wi::uhwi (TYPE_PRECISION (type),
> TYPE_PRECISION (op2.type ())),
> UNSIGNED))
> - return false;
> + goto done;
> if (shift == 0)
> {
> r = lhs;
> + r.intersect (adjust);
> return true;
> }
>
> @@ -2126,9 +2132,16 @@ operator_lshift::op1_range (irange &r,
>
> if (utype != type)
> range_cast (r, type);
> + r.intersect (adjust);
> return true;
> }
> - return false;
> +
> + done:
> + if (adjust.varying_p ())
> + return false;
> +
> + r = adjust;
> + return true;
> }
>
> bool
> diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr102546.c b/gcc/testsuite/gcc.dg/tree-ssa/pr102546.c
> new file mode 100644
> index 00000000000..4bd98747732
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr102546.c
> @@ -0,0 +1,23 @@
> +// { dg-do compile }
> +// { dg-options "-O3 -fdump-tree-optimized" }
> +
> +static int a;
> +static char b, c, d;
> +void bar(void);
> +void foo(void);
> +
> +int main() {
> + int f = 0;
> + for (; f <= 5; f++) {
> + bar();
> + b = b && f;
> + d = f << f;
> + if (!(a >= d || f))
> + foo();
> + c = 1;
> + for (; c; c = 0)
> + ;
> + }
> +}
> +
> +// { dg-final { scan-tree-dump-not "foo" "optimized" } }
> --
> 2.31.1
>
Bah. The range was being clobbered half way through the calculation.
Tested on x86-64 Linux.
Pushed.
On Fri, Oct 1, 2021 at 4:52 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>
> Well, after talking with Andrew it seems that X << Y being non-zero
> also implies X is non-zero. So we don't even need relationals here.
>
> So, I leave gori relationals in his capable hands, while I test this
> much simpler patch which fixes the PR with no additional
> infrastructure ;-).
>
> Will push pending tests.
> Aldy
>
> On Fri, Oct 1, 2021 at 2:43 PM Aldy Hernandez <aldyh@redhat.com> wrote:
> >
> > Knowing that X << X is non-zero means X is also non-zero. This patch
> > teaches this this to range-ops.
> >
> > As usual, the big twiddling experts could come up with all sorts of
> > fancy enhancements in this area, and we welcome all patches :).
> >
> > I will push this pending tests.
> >
> > gcc/ChangeLog:
> >
> > PR tree-optimization/102546
> > * range-op.cc (operator_lshift::op1_range): Handle EQ_EXPR
> > relation.
> > ---
> > gcc/range-op.cc | 19 ++++++++++++++++---
> > gcc/testsuite/gcc.dg/tree-ssa/pr102546.c | 23 +++++++++++++++++++++++
> > 2 files changed, 39 insertions(+), 3 deletions(-)
> > create mode 100644 gcc/testsuite/gcc.dg/tree-ssa/pr102546.c
> >
> > diff --git a/gcc/range-op.cc b/gcc/range-op.cc
> > index 5e37133026d..53f3be4266e 100644
> > --- a/gcc/range-op.cc
> > +++ b/gcc/range-op.cc
> > @@ -2075,9 +2075,14 @@ operator_lshift::op1_range (irange &r,
> > tree type,
> > const irange &lhs,
> > const irange &op2,
> > - relation_kind rel ATTRIBUTE_UNUSED) const
> > + relation_kind rel) const
> > {
> > tree shift_amount;
> > + int_range<2> adjust (type);
> > +
> > + if (rel == EQ_EXPR && !lhs.contains_p (build_zero_cst (type)))
> > + adjust.set_nonzero (type);
> > +
> > if (op2.singleton_p (&shift_amount))
> > {
> > wide_int shift = wi::to_wide (shift_amount);
> > @@ -2086,10 +2091,11 @@ operator_lshift::op1_range (irange &r,
> > if (wi::ge_p (shift, wi::uhwi (TYPE_PRECISION (type),
> > TYPE_PRECISION (op2.type ())),
> > UNSIGNED))
> > - return false;
> > + goto done;
> > if (shift == 0)
> > {
> > r = lhs;
> > + r.intersect (adjust);
> > return true;
> > }
> >
> > @@ -2126,9 +2132,16 @@ operator_lshift::op1_range (irange &r,
> >
> > if (utype != type)
> > range_cast (r, type);
> > + r.intersect (adjust);
> > return true;
> > }
> > - return false;
> > +
> > + done:
> > + if (adjust.varying_p ())
> > + return false;
> > +
> > + r = adjust;
> > + return true;
> > }
> >
> > bool
> > diff --git a/gcc/testsuite/gcc.dg/tree-ssa/pr102546.c b/gcc/testsuite/gcc.dg/tree-ssa/pr102546.c
> > new file mode 100644
> > index 00000000000..4bd98747732
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/tree-ssa/pr102546.c
> > @@ -0,0 +1,23 @@
> > +// { dg-do compile }
> > +// { dg-options "-O3 -fdump-tree-optimized" }
> > +
> > +static int a;
> > +static char b, c, d;
> > +void bar(void);
> > +void foo(void);
> > +
> > +int main() {
> > + int f = 0;
> > + for (; f <= 5; f++) {
> > + bar();
> > + b = b && f;
> > + d = f << f;
> > + if (!(a >= d || f))
> > + foo();
> > + c = 1;
> > + for (; c; c = 0)
> > + ;
> > + }
> > +}
> > +
> > +// { dg-final { scan-tree-dump-not "foo" "optimized" } }
> > --
> > 2.31.1
> >
On 10/2/2021 1:50 PM, Aldy Hernandez via Gcc-patches wrote:
> Bah. The range was being clobbered half way through the calculation.
>
> Tested on x86-64 Linux.
>
> Pushed.
>
> On Fri, Oct 1, 2021 at 4:52 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>> Well, after talking with Andrew it seems that X << Y being non-zero
>> also implies X is non-zero. So we don't even need relationals here.
>>
>> So, I leave gori relationals in his capable hands, while I test this
>> much simpler patch which fixes the PR with no additional
>> infrastructure ;-).
>>
>> Will push pending tests.
>> Aldy
>>
>> On Fri, Oct 1, 2021 at 2:43 PM Aldy Hernandez <aldyh@redhat.com> wrote:
>>> Knowing that X << X is non-zero means X is also non-zero. This patch
>>> teaches this this to range-ops.
>>>
>>> As usual, the big twiddling experts could come up with all sorts of
>>> fancy enhancements in this area, and we welcome all patches :).
>>>
>>> I will push this pending tests.
>>>
>>> gcc/ChangeLog:
>>>
>>> PR tree-optimization/102546
>>> * range-op.cc (operator_lshift::op1_range): Handle EQ_EXPR
>>> relation.
I'm going to assume this also fixes a similar ICE building the linux
kernel. One less thing to bisect today :-)
jeff
@@ -2075,9 +2075,14 @@ operator_lshift::op1_range (irange &r,
tree type,
const irange &lhs,
const irange &op2,
- relation_kind rel ATTRIBUTE_UNUSED) const
+ relation_kind rel) const
{
tree shift_amount;
+ int_range<2> adjust (type);
+
+ if (rel == EQ_EXPR && !lhs.contains_p (build_zero_cst (type)))
+ adjust.set_nonzero (type);
+
if (op2.singleton_p (&shift_amount))
{
wide_int shift = wi::to_wide (shift_amount);
@@ -2086,10 +2091,11 @@ operator_lshift::op1_range (irange &r,
if (wi::ge_p (shift, wi::uhwi (TYPE_PRECISION (type),
TYPE_PRECISION (op2.type ())),
UNSIGNED))
- return false;
+ goto done;
if (shift == 0)
{
r = lhs;
+ r.intersect (adjust);
return true;
}
@@ -2126,9 +2132,16 @@ operator_lshift::op1_range (irange &r,
if (utype != type)
range_cast (r, type);
+ r.intersect (adjust);
return true;
}
- return false;
+
+ done:
+ if (adjust.varying_p ())
+ return false;
+
+ r = adjust;
+ return true;
}
bool
new file mode 100644
@@ -0,0 +1,23 @@
+// { dg-do compile }
+// { dg-options "-O3 -fdump-tree-optimized" }
+
+static int a;
+static char b, c, d;
+void bar(void);
+void foo(void);
+
+int main() {
+ int f = 0;
+ for (; f <= 5; f++) {
+ bar();
+ b = b && f;
+ d = f << f;
+ if (!(a >= d || f))
+ foo();
+ c = 1;
+ for (; c; c = 0)
+ ;
+ }
+}
+
+// { dg-final { scan-tree-dump-not "foo" "optimized" } }