https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110873
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Last reconfirmed| |2023-08-03
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
GCC 13 had:
```
Registering value_relation (h_29 == h_13) (bb10) at h_29 = PHI <h_13(9)>
Loops range found for h_29: [irange] unsigned char [5, 5] NONZERO 0x5 and
calculated range :[irange] unsigned char [0, 5] NONZERO 0x7
Global Exported: h_29 = [irange] unsigned char [5, 5] NONZERO 0x5
Folding PHI node: h_29 = PHI <h_13(9)>
Queued PHI for removal. Folds to: 5
Folding statement: if (h_29 <= 4)
gimple_simplified to if (0 != 0)
gimple_simplified to if (0 != 0)
Folded into: if (0 != 0)
``
While trunk does:
```
redicate evaluates to: DON'T KNOW
Not folded
Registering value_relation (h_29 == h_13) (bb10) at h_29 = PHI <h_13(9)>
Global Exported: h_29 = [irange] unsigned char [0, 5] MASK 0xfe VALUE 0xe7
Folding PHI node: h_29 = PHI <h_13(9)>
No folding possible
Folding statement: if (h_29 <= 4)
Visiting conditional with predicate: if (h_29 <= 4)
With known ranges
h_29: [irange] unsigned char [0, 5] MASK 0xfe VALUE 0xe7
Predicate evaluates to: DON'T KNOW
Simplified relational if (h_29 <= 4)
into if (h_29 != 5)
Folded into: if (h_29 != 5)
```
Which totally misses that h_29 was just 5.
