1. A branch prediction feature in a computer system for improving branch prediction rate when utilizing a branch history table (BHT) with an instruction cache, and being able to use branch history developed for instruction lines replaced in the instruction cache, comprising the instruction cache (I-cache) comprised of I-cache rows for respectively storing instruction lines fetched from a second level cache (L 2 cache) in a storage hierarchy of the computer system, the L 2 cache comprised of L 2 rows for respectively storing instruction lines fetched from a system main storage in the storage hierarchy of the computer system, a hint instruction location being provided in each I-cache row, and a hint instruction location being provided in each L 2 -cache row, in response to an I-cache hit for a current instruction in an I-cache line, a hint processor for generating a hint instruction associated with the I-cache line, the hint instruction containing: a BHT entry and a branch mask indicating the location(s) of each branch instruction in the associated I-cache line, and a current index of the I-cache line in the I-cache, the hint processor storing the hint instruction in the hint instruction location in the current I-cache row for the current instruction, in response to an I-cache miss, an L 2 row containing a copy of the current I-cache instruction line and an associated hint instruction being located in the L 2 cache and copied into the current I-cache row, and forwarding the hint instruction to the hint processor to be executed, and a current BHT entry containing a prediction bit for the current instruction when the current instruction is a branch instruction, and the prediction bit being changed if the current instruction is determined to be incorrectly predicted for the current instruction.