On Fri, Apr 05, 2013 at 02:42:19PM -0600, Jeff Law wrote: > ? I must be missing something, the change causes an early bail out > from try_crossjump_to_edge. > > We don't want to raise the min to > 0 as that doesn't allow the user > to turn on this specific transformation.
The condition is if (nmatch < PARAM_VALUE (PARAM_MIN_CROSSJUMP_INSNS)) return false; // aka "don't crossjump" So, the smaller the N in --param min-crossjump-insns=N is, the more likely we crossjump. Thus N=0 should mean that it is most likely we crossjump, and as N=1 requires that at least one insn matches, N=0 would mean that even zero insns can match. If we for --param min-crossjump-insns=0 always return false, it means we never crossjump, so it is least likely that we crossjump, which corresponds to largest possible N, not smallest one. Jakub