improve r53741

* Remove branching by a==0 case

Before r53741:
% perf stat ./miniruby -e'a=100;i=0;while i<0xfffffff;i+=1;a=(a*557+2)%100000;end'

 Performance counter stats for './miniruby -vea=100;i=0;while
i<0xfffffff;i+=1;a=(a*557+2)%100000;end':

      16412.994492 task-clock (msec)         #    0.999 CPUs utilized
               195 context-switches          #    0.012 K/sec
                 2 cpu-migrations            #    0.000 K/sec
               876 page-faults               #    0.053 K/sec
       48488588328 cycles                    #    2.954 GHz
       18464835712 stalled-cycles-frontend   #   38.08% frontend cycles
idle
   <not supported> stalled-cycles-backend
       85665428518 instructions              #    1.77  insns per cycle
                                             #    0.22  stalled cycles
                                             #    per insn
       10207419707 branches                  #  621.911 M/sec
           6334713 branch-misses             #    0.06% of all branches

      16.426858699 seconds time elapsed

After this:
% perf stat ./miniruby -ve'a=100;i=0;while i<0xfffffff;i+=1;a=(a*557+2)%100000;end'

 Performance counter stats for './miniruby -vea=100;i=0;while i<0xfffffff;i+=1;a=(a*557+2)%100000;end':

      13363.540634 task-clock (msec)         #    0.999 CPUs utilized
               137 context-switches          #    0.010 K/sec
                 2 cpu-migrations            #    0.000 K/sec
               874 page-faults               #    0.065 K/sec
       39477429278 cycles                    #    2.954 GHz
       14615402375 stalled-cycles-frontend   #   37.02% frontend cycles idle
   <not supported> stalled-cycles-backend
       83514678452 instructions              #    2.12  insns per cycle
                                             #    0.18  stalled cycles per insn
        9401528135 branches                  #  703.521 M/sec
            432567 branch-misses             #    0.00% of all branches

      13.371484310 seconds time elapsed

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@53744 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

0 files changed, 0 insertions, 0 deletions