[Bug target/115086] New: bic is not used when the non-not part is a constant

[pinskia at gcc dot gnu.org via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115086

            Bug ID: 115086
           Summary: bic is not used when the non-not part is a constant
           Product: gcc
           Version: 15.0
            Status: UNCONFIRMED
          Keywords: missed-optimization
          Severity: enhancement
          Priority: P3
         Component: target
          Assignee: unassigned at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org
  Target Milestone: ---
            Target: aarch64

Take:
```
int g2(int a,int c)
{
  int b = 4 & ~c;
  return b;
}
```

Currently GCC produces:
```
g2:
        mvn     w0, w1
        and     w0, w0, 4
        ret
```
But producing bic is better for most (if not all) modern cores due to the
instruction that generates the constant would be "free". That is GCC should
produce:
```
g2:
        mov     w8, 4
        bic     w0, w8, w1
        ret
```

Which is what clang/LLVM produces.