Given code such as
#include <math.h>
float dz[100];
int foo()
{
int i;
for (i=0; i<100; i++) {
dz[i] = sqrtf(dz[i]);
}
}
Open64 generates (on X86) a sqrt instruction followed by a conditional
call to the sqrtf library function.
__sqrt_arg_temp_0 = dz[i];
__save_sqrt_temp_1 = _F4SQRT(__sqrt_arg_temp_0);
if(__save_sqrt_temp_1 != __save_sqrt_temp_1)
{
__save_sqrt_temp_1 = sqrtf(__sqrt_arg_temp_0);
}
Does anyone know the motivation for the library call? Is something
missing in the X86 hardware instruction, some error value in the library
that needs to be set, something else?
Seems like a pretty high performance penalty for this behavior.
Dror
PS gcc seems to do the same thing
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