This patch introduces the ROLBRd and RORBRd pseudo-instructions, which implemenent the "traditional" rotate operations; instead of the AVR rotate instructions that use the carry bit. The code is not optimized at all. Especially when dealing with loops of rotate instructions, this codegen should be improved some day.
Related bug: 41358 https://bugs.llvm.org/show_bug.cgi?id=41358
Note: This is my first submitted patch.