https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111431
Bug ID: 111431
Summary: a & (a == 0) is not optimized to 0
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Keywords: missed-optimization, xfail
Severity: normal
Priority: P3
Component: tree-optimization
Assignee: unassigned at gcc dot gnu.org
Reporter: pinskia at gcc dot gnu.org
Target Milestone: ---
Take:
```
int
foo (int a)
{
int b = !a;
return (a & b);
}
```
The general rule is:
(a == CST) & a
transform into:
(CST & 1) ? (a == CST) : 0
So
(simplify
(bit_and:c (convert@2 (eq @0 INTEGER_CST@1)) @0)
(if ((wi::to_wide (@1) & 1) != 0)
@2
{ build_zero_cst (type); }))
