https://gcc.gnu.org/bugzilla/show_bug.cgi?id=88713
--- Comment #27 from Chris Elrod <elrodc at gmail dot com> --- g++ -mrecip=all -O3 -fno-signed-zeros -fassociative-math -freciprocal-math -fno-math-errno -ffinite-math-only -fno-trapping-math -fdump-tree-optimized -S -march=native -shared -fPIC -mprefer-vector-width=512 -fno-semantic-interposition -o gppvectorization_test.s vectorization_test.cpp is not enough to get vrsqrt. I need -funsafe-math-optimizations for the instruction to appear in the asm.