https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110450
Andrew Pinski <pinskia at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Ever confirmed|0 |1
Last reconfirmed| |2023-07-01
--- Comment #1 from Andrew Pinski <pinskia at gcc dot gnu.org> ---
In VRP:
trunk:
```
Folding statement: _11 = _9 % 11;
Matching expression match.pd:2480, gimple-match-4.cc:35
Matching expression match.pd:2483, gimple-match-3.cc:66
Matching expression match.pd:2490, gimple-match-2.cc:58
Matching expression match.pd:1991, gimple-match-5.cc:23
Matching expression match.pd:2480, gimple-match-4.cc:35
Matching expression match.pd:2483, gimple-match-3.cc:66
Matching expression match.pd:2490, gimple-match-2.cc:58
Matching expression match.pd:1948, gimple-match-7.cc:20
Matching expression match.pd:2480, gimple-match-4.cc:35
Matching expression match.pd:2483, gimple-match-3.cc:66
Matching expression match.pd:2490, gimple-match-2.cc:58
Applying pattern match.pd:5319, gimple-match-8.cc:2688
Applying pattern match.pd:6000, gimple-match-10.cc:587
Applying pattern match.pd:2102, gimple-match-1.cc:6289
Applying pattern match.pd:6000, gimple-match-10.cc:587
Applying pattern match.pd:5284, gimple-match-4.cc:1099
Applying pattern match.pd:1378, gimple-match-3.cc:7680
Applying pattern match.pd:4720, gimple-match-1.cc:16033
gimple_simplified to _14 = a.1_2 <= 0;
_15 = (int) _14;
_11 = _15 << 3;
Global Exported: _11 = [irange] int [0, 0][8, 8] NONZERO 0x8
Folded into: _11 = _15 << 3;
```
And the relationship between _5 and _11 is completely lost.
while in GCC 13:
```
Folding statement: _11 = _9 % 11;
Global Exported: _11 = [irange] int [0, 0][8, 8] NONZERO 0x8
Folded into: _11 = _9;
```
And then we remove the __builtin_unreachable even though we infer that _5 would
be 0 and therefore _11 would never be 8 .
