[PATCH] D77815: [flang] Fix setting mxcsr on MSVC

[Jean Perier via Phabricator via llvm-commits]

jeanPerier added a comment.

> Looks like `originalFenv_` is still used for restoring the original state. Shall I change the type of `originalFenv_` to be `unsigned int` on x86_64? (Or maybe a union?)
>  From what I understand `originalFenv_` is used for changing and restoring the `__mxcsr` value (or its equivalents on aarch64).

In host.cpp,  `originalFenv_` is more than just the `__mxcsr`, it also backs-up the whole fp environment (original rounding mode, exceptions that were raised,...) before calling the run-time to fold. Interrupts are also disabled between the related `feholdexcept` / `fesetenv` (we do not want the compiler to crash if the Fortran code being folded is wrong and triggers a division by zero or such), so it should be kept.
`currentFenv_` however was only about manipulating the `__mxcsr` (or `__fpcr `/...), so you can remove it where you do not need it anymore.


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  https://reviews.llvm.org/D77815/new/

https://reviews.llvm.org/D77815