* [COMMITTED] frange::maybe_isnan() should return FALSE for undefined ranges.
@ 2022-09-20 18:22 Aldy Hernandez
2022-09-21 7:38 ` Richard Biener
0 siblings, 1 reply; 4+ messages in thread
From: Aldy Hernandez @ 2022-09-20 18:22 UTC (permalink / raw)
To: GCC patches; +Cc: Andrew MacLeod, Aldy Hernandez
Undefined ranges have undefined NAN bits. We can't depend on them,
as they may contain garbage. This patch returns false from
maybe_isnan() for undefined ranges (the empty set).
gcc/ChangeLog:
* value-range.h (frange::maybe_isnan): Return false for
undefined ranges.
---
gcc/value-range.h | 2 ++
1 file changed, 2 insertions(+)
diff --git a/gcc/value-range.h b/gcc/value-range.h
index 7d5584a9294..325ed08f290 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -1210,6 +1210,8 @@ frange::known_isinf () const
inline bool
frange::maybe_isnan () const
{
+ if (undefined_p ())
+ return false;
return m_pos_nan || m_neg_nan;
}
--
2.37.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [COMMITTED] frange::maybe_isnan() should return FALSE for undefined ranges.
2022-09-20 18:22 [COMMITTED] frange::maybe_isnan() should return FALSE for undefined ranges Aldy Hernandez
@ 2022-09-21 7:38 ` Richard Biener
2022-09-21 7:52 ` Aldy Hernandez
0 siblings, 1 reply; 4+ messages in thread
From: Richard Biener @ 2022-09-21 7:38 UTC (permalink / raw)
To: Aldy Hernandez; +Cc: GCC patches
On Tue, Sep 20, 2022 at 8:23 PM Aldy Hernandez via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> Undefined ranges have undefined NAN bits. We can't depend on them,
> as they may contain garbage.
Ick ;) Can you add a comment at least?
> This patch returns false from
> maybe_isnan() for undefined ranges (the empty set).
>
> gcc/ChangeLog:
>
> * value-range.h (frange::maybe_isnan): Return false for
> undefined ranges.
> ---
> gcc/value-range.h | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/gcc/value-range.h b/gcc/value-range.h
> index 7d5584a9294..325ed08f290 100644
> --- a/gcc/value-range.h
> +++ b/gcc/value-range.h
> @@ -1210,6 +1210,8 @@ frange::known_isinf () const
> inline bool
> frange::maybe_isnan () const
> {
> + if (undefined_p ())
> + return false;
> return m_pos_nan || m_neg_nan;
> }
>
> --
> 2.37.1
>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [COMMITTED] frange::maybe_isnan() should return FALSE for undefined ranges.
2022-09-21 7:38 ` Richard Biener
@ 2022-09-21 7:52 ` Aldy Hernandez
2022-09-21 9:36 ` Richard Biener
0 siblings, 1 reply; 4+ messages in thread
From: Aldy Hernandez @ 2022-09-21 7:52 UTC (permalink / raw)
To: Richard Biener; +Cc: GCC patches
[-- Attachment #1: Type: text/plain, Size: 1314 bytes --]
The reason the flags were uninitialized was because they were unused,
similarly for m_type. But you're right, it is icky and prone to bugs.
I just thought it was cheap to set_undefined by just flipping
m_kind=VR_UNDEFINED, but it smells like premature optimization.
How about this?
Aldy
On Wed, Sep 21, 2022 at 9:39 AM Richard Biener
<richard.guenther@gmail.com> wrote:
>
> On Tue, Sep 20, 2022 at 8:23 PM Aldy Hernandez via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
> >
> > Undefined ranges have undefined NAN bits. We can't depend on them,
> > as they may contain garbage.
>
> Ick ;) Can you add a comment at least?
>
> > This patch returns false from
> > maybe_isnan() for undefined ranges (the empty set).
> >
> > gcc/ChangeLog:
> >
> > * value-range.h (frange::maybe_isnan): Return false for
> > undefined ranges.
> > ---
> > gcc/value-range.h | 2 ++
> > 1 file changed, 2 insertions(+)
> >
> > diff --git a/gcc/value-range.h b/gcc/value-range.h
> > index 7d5584a9294..325ed08f290 100644
> > --- a/gcc/value-range.h
> > +++ b/gcc/value-range.h
> > @@ -1210,6 +1210,8 @@ frange::known_isinf () const
> > inline bool
> > frange::maybe_isnan () const
> > {
> > + if (undefined_p ())
> > + return false;
> > return m_pos_nan || m_neg_nan;
> > }
> >
> > --
> > 2.37.1
> >
>
[-- Attachment #2: 0002-Clear-unused-flags-in-frange-for-undefined-ranges.patch --]
[-- Type: text/x-patch, Size: 2074 bytes --]
From f96eb8f4386f2cec67dbf20ab3650aa756fe218a Mon Sep 17 00:00:00 2001
From: Aldy Hernandez <aldyh@redhat.com>
Date: Wed, 21 Sep 2022 09:49:14 +0200
Subject: [PATCH] Clear unused flags in frange for undefined ranges.
gcc/ChangeLog:
* value-range.cc (frange::combine_zeros): Call set_undefined.
(frange::intersect_nans): Same.
(frange::intersect): Same.
(frange::verify_range): Undefined ranges do not have a type.
* value-range.h (frange::set_undefined): Clear NAN flags and type.
---
gcc/value-range.cc | 8 ++++----
gcc/value-range.h | 4 ++++
2 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/gcc/value-range.cc b/gcc/value-range.cc
index dc42b6d3120..505eb9211a7 100644
--- a/gcc/value-range.cc
+++ b/gcc/value-range.cc
@@ -422,7 +422,7 @@ frange::combine_zeros (const frange &r, bool union_p)
if (maybe_isnan ())
m_kind = VR_NAN;
else
- m_kind = VR_UNDEFINED;
+ set_undefined ();
changed = true;
}
return changed;
@@ -506,7 +506,7 @@ frange::intersect_nans (const frange &r)
if (maybe_isnan ())
m_kind = VR_NAN;
else
- m_kind = VR_UNDEFINED;
+ set_undefined ();
if (flag_checking)
verify_range ();
return true;
@@ -558,7 +558,7 @@ frange::intersect (const vrange &v)
if (maybe_isnan ())
m_kind = VR_NAN;
else
- m_kind = VR_UNDEFINED;
+ set_undefined ();
if (flag_checking)
verify_range ();
return true;
@@ -696,7 +696,7 @@ frange::verify_range ()
switch (m_kind)
{
case VR_UNDEFINED:
- // m_type is ignored.
+ gcc_checking_assert (!m_type);
return;
case VR_VARYING:
gcc_checking_assert (m_type);
diff --git a/gcc/value-range.h b/gcc/value-range.h
index 325ed08f290..3668b331187 100644
--- a/gcc/value-range.h
+++ b/gcc/value-range.h
@@ -1083,6 +1083,10 @@ inline void
frange::set_undefined ()
{
m_kind = VR_UNDEFINED;
+ m_type = NULL;
+ m_pos_nan = false;
+ m_neg_nan = false;
+ // m_min and m_min are unitialized as they are REAL_VALUE_TYPE ??.
if (flag_checking)
verify_range ();
}
--
2.37.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [COMMITTED] frange::maybe_isnan() should return FALSE for undefined ranges.
2022-09-21 7:52 ` Aldy Hernandez
@ 2022-09-21 9:36 ` Richard Biener
0 siblings, 0 replies; 4+ messages in thread
From: Richard Biener @ 2022-09-21 9:36 UTC (permalink / raw)
To: Aldy Hernandez; +Cc: GCC patches
On Wed, Sep 21, 2022 at 9:52 AM Aldy Hernandez <aldyh@redhat.com> wrote:
>
> The reason the flags were uninitialized was because they were unused,
> similarly for m_type. But you're right, it is icky and prone to bugs.
> I just thought it was cheap to set_undefined by just flipping
> m_kind=VR_UNDEFINED, but it smells like premature optimization.
>
> How about this?
LGTM
>
> Aldy
>
> On Wed, Sep 21, 2022 at 9:39 AM Richard Biener
> <richard.guenther@gmail.com> wrote:
> >
> > On Tue, Sep 20, 2022 at 8:23 PM Aldy Hernandez via Gcc-patches
> > <gcc-patches@gcc.gnu.org> wrote:
> > >
> > > Undefined ranges have undefined NAN bits. We can't depend on them,
> > > as they may contain garbage.
> >
> > Ick ;) Can you add a comment at least?
> >
> > > This patch returns false from
> > > maybe_isnan() for undefined ranges (the empty set).
> > >
> > > gcc/ChangeLog:
> > >
> > > * value-range.h (frange::maybe_isnan): Return false for
> > > undefined ranges.
> > > ---
> > > gcc/value-range.h | 2 ++
> > > 1 file changed, 2 insertions(+)
> > >
> > > diff --git a/gcc/value-range.h b/gcc/value-range.h
> > > index 7d5584a9294..325ed08f290 100644
> > > --- a/gcc/value-range.h
> > > +++ b/gcc/value-range.h
> > > @@ -1210,6 +1210,8 @@ frange::known_isinf () const
> > > inline bool
> > > frange::maybe_isnan () const
> > > {
> > > + if (undefined_p ())
> > > + return false;
> > > return m_pos_nan || m_neg_nan;
> > > }
> > >
> > > --
> > > 2.37.1
> > >
> >
^ permalink raw reply [flat|nested] 4+ messages in thread
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2022-09-20 18:22 [COMMITTED] frange::maybe_isnan() should return FALSE for undefined ranges Aldy Hernandez
2022-09-21 7:38 ` Richard Biener
2022-09-21 7:52 ` Aldy Hernandez
2022-09-21 9:36 ` Richard Biener
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