[clang-tools-extra] [libc] [compiler-rt] [lldb] [flang] [clang] [llvm] [mlir] [DAGCombiner] Combine frem into fdiv+ftrunc+fma (PR #67642)

[Qiu Chaofan via cfe-commits]

ecnelises wrote:

I tested with a number of random floating values. In most of the cases, the expanded result is exactly the same as libcall result.

But when `fmod(a,b)` is very close to `b` (smaller than `1e-10`, for example, `fmod(521862.045173469, 31.048432006988875)`), the result would be totally wrong..  I'm thinking about a solution.

https://github.com/llvm/llvm-project/pull/67642