load effective address
x86-64's lea instruction, which works out an address with the memory-operand rules and puts the number in a register without touching memory.
lea dest, [address expression] writes the effective address to dest and performs no memory access and changes no other state, which compilers also exploit for adds and small multiplies.
Examples
lea rax, [rdi + rdi*2]computesrdi× 3 without reading memory.
See also