SSE addition producing garbage - c++

Question

I am trying to compare SSE float[4] addition to standard float[4] addition. I tried this:
#include <iostream>
#include <vector>
struct Point4
{
Point4()
{
data[0] = 0;
data[1] = 0;
data[2] = 0;
data[3] = 0;
}
float data[4];
};
static float SumOfDifferences(const Point4& a, const Point4& b)
{
// This function only returns the sum of the sum of the components
float sumValues = 0.0f;
for(unsigned int i = 0; i < 4; ++i)
{
sumValues += a.data[i] + b.data[i];
}
return sumValues;
}
void Standard()
{
Point4 a;
a.data[0] = 1;
a.data[1] = 2;
a.data[2] = 3;
a.data[3] = 4;
Point4 b;
b.data[0] = 1;
b.data[1] = 6;
b.data[2] = 3;
b.data[3] = 5;
float total = 0.0f;
for(unsigned int i = 0; i < 1e6; ++i)
{
total += SumOfDifferences(a, b);
}
std::cout << "total: " << total << std::endl;
}
void Vectorized()
{
typedef int v4sf __attribute__ (( vector_size(4*sizeof(float)) ));
v4sf a;
float* aPointer = (float*)&a;
aPointer[0] = 1; aPointer[1] = 2; aPointer[2] = 3; aPointer[3] = 4;
v4sf b;
float* bPointer = (float*)&b;
bPointer[0] = 1; bPointer[1] = 2; bPointer[2] = 3; bPointer[3] = 4;
float total = 0.0f;
v4sf result;
float* resultPointer = (float*)&result;
for(unsigned int i = 0; i < 1e6; ++i)
{
result = a + b; // Vectorized operation
// Sum the components of the result (this is done with the "total += " in the Standard() loop
for(unsigned int component = 0; component < 4; ++component)
{
total += resultPointer[component];
}
}
std::cout << "total: " << total << std::endl;
}
int main()
{
// Standard();
Vectorized();
return 0;
}
but the output is 'inf' for the Vectorized() function. When I stepped through with a debugger, the values of 'result' seem to be garbage (i'd expect them to be (0, 4, 0, 1) ). Where am I going wrong here?

Answer 1

Try typedef float v4sf __attribute__ (( vector_size(4*sizeof(float)) ));
I get 2e+07 as the result.