When the scavenger is not allowed to spill, the only difference between forward and backward should be the heuristics used to pick an available register. Forwards scavenging tries to pick a register that can be used again later in the BB; backwards scavenging tries to pick one that can be used earlier. Backwards scavenging is preferred because it does not rely on accurate kill flags. Differential Revision: https://reviews.llvm.org/D151323
310 KiB
310 KiB