This is a special case of Z / (X / Y) => (Y * Z) / X, with X = 1.0. The m_OneUse check is avoided because even in the case of the multiple uses for 1.0/Y, the number of instructions remain the same and a division is replaced by a multiplication.
The following testcase is added.
test/Transforms/InstCombine/fdiv-to-fmul-opt.ll