I'm looking at the AVX programming reference. The new Haswell instructions include some eagerly awaited "gather" loads. However, I can't figure out what the alignment restrictions are on the indexed data items. Section 2.5 "Memory alignment" of the reference seems like it ought to list the various VGATHER* instructions in one of tables 2.4 or 2.5... but it doesn't.
Background: while gather instructions' supported data sizes are 4 and 8 bytes, my application could benefit from gather-loading adjacent 16-bit data value pairs to DWORDS. Odd indices with a 2-byte scale will produce 2-byte aligned 4-byte loads and it's not clear to me from the manual whether this will fault or otherwise fail to work as intended (I do rather suspect I'm out of luck given all the instructions supporting unaligned accesses seem to have a 'U' in them).
Thanks for any clarification