[libc-commits] [libc] [libc][C23][math] Implement cospif function correctly rounded for all rounding modes (PR #97464)

[via libc-commits]

lntue wrote:

@HendrikHuebner you can add the following test cases to smoke tests:
```
  EXPECT_FP_EQ_ALL_ROUNDING(zero, LIBC_NAMESPACE::cospif(0.5f));
  EXPECT_FP_EQ_ALL_ROUNDING(neg_zero, LIBC_NAMESPACE::cospif(-0.5f));
```


https://github.com/llvm/llvm-project/pull/97464