Thiago Macieira of Intel is coordinating a proposal to enable SSE2 by default for the 32-bit builds of the Qt tool-kit beginning with the Qt 5.3 release. This likely change is due to the V4 JIT engine generating floating-point math for Qt's QML only using SSE x86 registers...
November 11, 2013
Qt 5.3 Might Depend On SSE2 CPUs
Read more at Phoronix