On 22 August 2007 11:13, Andrew Pinski wrote:
> On 8/21/07, tbp <[EMAIL PROTECTED]> wrote:
>> # /usr/local/gcc-4.3-svn.old6/bin/g++ vecop.cc
>> vecop.cc: In function 'T foo() [with T = float __vector__]':
>> vecop.cc:13: instantiated from here
>> vecop.cc:4: error: invalid operands of types 'float __vector__' and
>> 'float __vector__' to binary 'operator|'
>> vecop.cc:5: error: invalid operands of types 'float __vector__' and
>> 'float __vector__' to binary 'operator&'
>> vecop.cc:6: error: invalid operands of types 'float __vector__' and
>> 'float __vector__' to binary 'operator^'
>>
>> Apparently it's still there as of right now, on x86-64 at least. I think
>> this is not supposed to happen but i'm not sure, hence the mail.
>
> This is internally, float|float does not make sense so how can vector
> float | vector float make sense (likewise for & and ^).
float InvSqrt (float x){
float xhalf = 0.5f*x;
int i = *(int*)&x;
i = 0x5f3759df - (i>>1);
x = *(float*)&i;
x = x*(1.5f - xhalf*x*x);
return x;
}
It's not exactly what you're referring to, but it's evidence in favour of the
argument that we should never presume anything, no matter how unusual, might
not have a reasonable use. (However as I said, I'm not arguing against the
error message, since it's still possible to express this intent using casts.)
cheers,
DaveK
--
Can't think of a witty .sigline today....
