SIMD shift instructions: shl, sshr, ushr are incorrectly encoded. Shift bits are currently directly written into bitfield. However, according to spec, it should be
"<type-dependent-constant> - UInt(immh:immb)" for right shifts and UInt(immh:immb) - "<type-dependent-constant>" for left shift.

These instructions are not used in current codebase, so, this problem wasn't found earlier.