[Bug c/114746] With FLT_EVAL_METHOD = 2, -fexcess-precision=fast reduces the precision of floating-point constants and floating-point constant expressions

[vincent-gcc at vinc17 dot net via Gcc-bugs]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=114746

--- Comment #6 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
(In reply to Jakub Jelinek from comment #5)
> FLT_EVAL_METHOD = 0 is on some hw like the pre-SSE2 ia32 extremely
> expensive, far more so than even the very expensive -ffloat-store.  That is
> certainly not a good default.  Plus I'm afraid it would suffer from double
> rounding, unless the floating point state is switched each time one needs to
> perform some floating point instruction in a different precision.

I would think that in general, users would choose a FP type and stick to it.
However, there is the problem of libraries.

But I would be interested to know what would be the actual loss in practice,
for the use of such machines nowadays (if users want performance, there are
faster processors, with SSE2 support).