https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110753
Aldy Hernandez <aldyh at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |aldyh at gcc dot gnu.org
Assignee|unassigned at gcc dot gnu.org |aldyh at gcc dot gnu.org
--- Comment #3 from Aldy Hernandez <aldyh at gcc dot gnu.org> ---
The intersection of two mask/value pairs is being pessimized incorrectly.
MASK 0x0 VALUE 0x1 (value is known to be 1)
MASK 0xfffffffffffffffc VALUE 0x0 (low 2 bits are known to be 1, everything
else is unknown).
irange_bitmask::intersect() is intersecting these to:
MASK 0xffffffffffffffff VALUE 0x0
(i.e. totally unknown value).
This is causing union_bitmask() to return a change when none actually occurred,
because we end up losing the bitmask.
Mine.
