Around 5% of the instructions in a C program are register reordering code introduced by the register allocator (assuming x86 and an optimizing compiler). I do n

Around 5% of the instructions in a C program are register reordering code introduced by the register allocator (assuming x86 and an optimizing compiler). I do not know the percentage of the register spilling code, which comes on top of this. Effectively, an LLVM JIT also produces shuffle code, but the programmer can use variable names instead of stack reorder operations.