GCC beaten by ICC in stupid trig test!

[Robert Dewar]

Joe Buck wrote:

>>I'm aware of the usual examples.  Do you think that we need yet another 
>>fast-math flag to allow the compiler to reassociate values in 
>>floating-point arithmetic? -freally-unsafe-math-optimizations perhaps?  
>>Or maybe such a programmer as you describe will just turn off 
>>-funsafe-math-optimizations.
> 
> 
> No.  Why would we need such a thing?  If the user does not care about
> order of evaluation, the user can write a+b+c .

That's an appropriate statement for Fortran, but not for other languages
like C, C++ and Ada, where a+b+c is semantically equivalent to (a+b)+c
and the reassociation is not allowed in either case.

I dislike anything being called an optimization, unsafe or not, when it
is not an optimization but in fact a distortion of required language
semantics.