This generates bitcode which is indistinguishable from what was
hand-written for int32 types in v[load|store]_impl.ll.
v4: Use vec2+scalar for vec3 load/stores to prevent corruption (per Tom)
v3: Also remove unused generic/lib/shared/v[load|store]_impl.ll
v2: (Per Matt Arsenault) Fix alignment issues with vector load stores
Signed-off-by: Aaron Watry <email@example.com>