https://gcc.gnu.org/bugzilla/show_bug.cgi?id=126704
Drea Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Ever confirmed|0 |1
Target Milestone|--- |17.0
Last reconfirmed| |2026-08-12
Summary|Missing or not complete |[17 Regression] Missing or
|global range after VRP2 |not complete global range
|(with and without dom) |after VRP2 (with and
| |without dom) since r17-1845
Status|UNCONFIRMED |ASSIGNED
Assignee|unassigned at gcc dot gnu.org |pinskia at gcc dot
gnu.org
--- Comment #2 from Drea Pinski <pinskia at gcc dot gnu.org> ---
So the DCE issue is reassociation not removing statements no longer reference.
Let me look into that next.
Optimizing range tests i_4 +[, 99999] and +[0, 99999]
into (unsigned int) i_4 <= 99999
Transforming _8 = _6 | _7;
into _8 = _11;
Transforming:
i.0_1 = (unsigned int) i_4;
_6 = i.0_1 > 99999;
_7 = i_4 > 99999;
_8 = _6 | _7;
into:
i.0_1 = (unsigned int) i_4;
_6 = i.0_1 > 99999;
_12 = (unsigned int) i_4;
_11 = _12 > 99999;
_7 = i_4 > 99999;
_8 = _11;
if (_8 != 0)
Looks like the reassociation issue is the issue with DOM too.
But there looks like a missing match pattern here for:
i.0_1 = (unsigned int) i_4;
_6 = i.0_1 > 99999;
_7 = i_4 > 99999;
_8 = _6 | _7;
into:
i.0_1 > 99999
Which would have fixed the issue too.
The missed optimization is also a regression. It was exposed by
r17-1845-g23b6a9a41a5c05 .
So I will implement two patches, one for the missed match pattern and one for
the reassociation.
