The IA-32 instruction set does distignuish between integer and floating point bitiwse operations. In addition to the single-precision floating-point bitwise instructions that tbp mentioned (ORPS, ANDPS, ANDNPS and XORPS) there are both distinct double-precision floating-point bitwise instructions (ORPD, ANDPD, ANDNPD and XORPD) and integer bitwise instructions (POR, PAND, PANDN and PXOR). While these operations all do the same thing, they can differ in performance depending on the context.
Oops, I only remembered PS vs. PD (I remembered POR as MMX instructions only). I believe that optimizing this should be a task for the x86 machine dependent reorg.
Paolo
