CCS/MSP430FR5969: Do processors work better on Byte and Words than Bits?

When you want to change a single bit, you either have to use separate one-byte variables for each bit, or you have to mask out the bit so that the other bits in the variable are not affected.

The MSP430 has BIS/BIC instructions to set/clear bits, but this would still require two instructions:

// one byte
a = new_value;

// one bit
a &= ~BIT_MASK;
a |= new_bit;

If you do not know the bit number, you have to add more instructions for shitfting.

The MSP430 does not have a barrel shifter; more shift steps need more cycles.

I am sorry but my concern remain still at the same state. Allow me to share an example to explain the doubt I have.

Suppose, int x = 2; and in another variable int result=0; I am supposed to get the twice of variable x. Now, in (Case 1) I make the use of arithmetic operators and I write something like:

result = x * 2; 

whereas in (Case 2) I make the use of shift operator and write something like:

 result = x<<1;

Could you please elaborate that which case is likely to execute faster and why?
Is the statement in the CRC pdf Document, applicable for most of the CPU's or just MSP430's ?

Clemens Ladisch said:

But CRC does not use multiplication; it is defined on a bit stream, and that is what the application note is talking about.

Thanks. Pretty much puts most of my questions to rest.