CODEWITHSUNDEEP
c++simdintrinsicsavx
user1315172
user1315172

Reputation: 147

Intel SIMD - How can I check if an __m256* contains any non-zero values

I am using the Microsoft Visual Studio compiler. I am trying to find out if a 256 bit vector contains any non-zero values. I have tried res_simd = ! _mm256_testz_ps(*pSrc1, *pSrc1); but it does not work.

Upvotes: 6

Views: 2927

Answers (1)

Paul R
Paul R

Reputation: 212979

_mm256_testz_ps just tests the sign bits - in order to test the values you'll need to compare against 0 and then extract the resulting mask, e.g.

__m256 vcmp = _mm256_cmp_ps(*pSrc1, _mm256_set1_ps(0.0f), _CMP_EQ_OQ);
int mask = _mm256_movemask_ps(vcmp);
bool any_nz = mask != 0xff;

Upvotes: 9

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