Re: FWD: FLOATING-POINT CONSISTENCY, -FFLOAT-STORE, AND X86

[Craig Burley <burley@gnu.org>]

>> A little thought, planning, and lack of -O flags, and you can get huge
>> benefits from the 80-bit cells.
>
>It would seem that if we did 80-bit spills, then the -O flags would not
>affect the results (assuming that the original code uses parentheses
>to constrain the order of evaluation of FP expressions and that the
>optimizer avoids transformations that can change numerical results,
>such as pre-evaluating expressions with 64-bit that would otherwise
>be evaluated using 80-bit precision at runtime).

I wouldn't want us to say that, even assuming my proposal was adopted,
until we'd done at least a minimal audit of the compiler to reassure
ourselves that it was true.  Certainly I don't have enough confidence
or expertise to say it.

But it'd probably be nice if it was true, or could at least be made true
using an option or two!

        tq vm, (burley)