[clang] `__builtin_elementwise_exp` and `__builtin_exp` behave different when controlling FP behavior explicitly

[FantasqueX]

https://godbolt.org/z/ne66d34Ga

When controlling FP behavior explicitly, __builtin_elementwise_exp doesn't honor it while __builtin_exp does. I think they should behave consistently.

[llvmbot]

@llvm/issue-subscribers-clang-codegen

Author: Letu Ren (FantasqueX)

https://godbolt.org/z/ne66d34Ga

When controlling FP behavior explicitly, __builtin_elementwise_exp doesn't honor it while __builtin_exp does. I think they should behave consistently.