According to Intel's Optimization Reference Manual for SNB+: " For LEA instructions with three source operands and some specific situations, instruction latency has increased to 3 cycles, and must dispatch via port 1: - LEA that has all three source operands: base, index, and offset - LEA that uses base and index registers where the base is EBP, RBP,or R13 - LEA that uses RIP relative addressing mode - LEA that uses 16-bit addressing mode "
This patch currently handles the first 2 cases only.