math: remove ieee_arithmetic import

[VincentVanlaer]

Importing any of the ieee modules has a somewhat unexpected effect. Each procedure that has an ieee module in scope will (1) save the FPU state at the start and (2) restore it at the end, adding any flags that were raised by the procedure. Since the use ieee_arithmetic is included in the main math module directly, everything that imports math will be effectively be importing an ieee module. This has a large impact on performance (for example, the low_z test case runs in 2/3 the time with this patch).

[rhdtownsend]

I’m thinking more about Vincent’s interpretation here: "Each procedure that has an ieee module in scope will (1) save the FPU state at the start and (2) restore it at the end, adding any flags that were raised by the procedure. Since the use ieee_arithmetic is included in the main math module directly, everything that imports math will be effectively be importing an ieee module. This has a large impact on performance (for example, the low_z test case runs in 2/3 the time with this patch).” But none of the IEEE functions are made public from the math module, so surely importing the math module should not mean that the IEEE module is in scope?

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On Feb 17, 2026, at 8:18 AM, Vincent Vanlaer ***@***.***> wrote: Merged #920 into main. — Reply to this email directly, view it on GitHub, or unsubscribe. You are receiving this because your review was requested.Message ID: ***@***.***>

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[VincentVanlaer]

so surely importing the math module should not mean that the IEEE module is in scope?

gfortran seems to think otherwise. I tracked down where in the code it was adding the save/restore functions, and from what I can tell it just checks whether any symbols from any ieee modules are in scope (for whatever definition of scope is used within gfortran). Perhaps worthy of a bug report, but that might take a while to go through the pipeline.