https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112626
Bug ID: 112626
Summary: `ABS(a) CMP a` can be optimized
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: missed-optimization
Severity: enhancement
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
This assumes, non-wrapping types, non-signed zero types
`abs(a) >= a` -> true
`abs(a) < a` -> false
`abs(a) <= a` -> `a >= 0`
`abs(a) == a` -> `a >= 0`
`abs(a) != a` -> `a < 0`
`abs(a) > a` -> `a < 0`
For wrapping types (non-signed zero types) or `((type)absu)`:
`abs(a) >= a` -> `a != TYPE_MIN`
`abs(a) < a` -> `a == TYPE_MIN`
`abs(a) != a` -> `a < 0 & a != TYPE_MIN`
`abs(a) > a` -> `a < 0 & a != TYPE_MIN`
`abs(a) == a` -> `a >= 0 | a == TYPE_MIN`
`abs(a) <= a` -> `a >= 0 | a == TYPE_MIN`
