YJIT: Handle rest+splat where non-splat < required

[jimmyhmiller]

Here are the stats of railsbench and liquid-render before and after these changes

Highlight here is railsbench

Before:
 iseq_has_rest_and_splat_fewer:     10,610 ( 3.3%)
After:
 n/a

Rails Bench Before

         ***YJIT: Printing YJIT statistics on exit***
method call exit reasons: 
                          block_arg:     64,789 (20.2%)
                        iseq_zsuper:     60,078 (18.7%)
            iseq_has_rest_and_block:     54,471 (17.0%)
                   iseq_arity_error:     30,685 ( 9.6%)
                iseq_ruby2_keywords:     25,058 ( 7.8%)
                     iseq_has_no_kw:     17,298 ( 5.4%)
          args_splat_cfunc_var_args:     16,295 ( 5.1%)
                           kw_splat:     12,997 ( 4.1%)
      iseq_has_rest_and_splat_fewer:     10,610 ( 3.3%)
                    iseq_has_kwrest:      7,319 ( 2.3%)
                  klass_megamorphic:      7,069 ( 2.2%)
           iseq_missing_optional_kw:      4,054 ( 1.3%)
               iseq_has_rest_and_kw:      2,183 ( 0.7%)
         iseq_has_rest_and_optional:      2,015 ( 0.6%)
             args_splat_cfunc_zuper:      2,002 ( 0.6%)
                      iseq_has_post:      1,988 ( 0.6%)
              cfunc_ruby_array_varg:      1,360 ( 0.4%)
                           keywords:        102 ( 0.0%)
    args_splat_cfunc_ruby2_keywords:         62 ( 0.0%)
                    args_splat_ivar:         50 ( 0.0%)
                      zsuper_method:         14 ( 0.0%)
                        send_getter:         12 ( 0.0%)
                args_splat_opt_call:          5 ( 0.0%)
        splatarray_length_not_equal:          2 ( 0.0%)
                    ivar_set_method:          2 ( 0.0%)
                  bmethod_block_arg:          2 ( 0.0%)
invokeblock exit reasons: 
      proc:      2,248 (92.7%)
    symbol:        176 ( 7.3%)
invokesuper exit reasons: 
    me_changed:      4,792 (68.6%)
         block:      2,194 (31.4%)
leave exit reasons: 
        interp_return:  1,754,442 (97.6%)
    start_pc_non_zero:     43,884 ( 2.4%)
         se_interrupt:         28 ( 0.0%)
getblockparamproxy exit reasons: 
    block_param_modified:          3 (100.0%)
getinstancevariable exit reasons:
    (all relevant counters are zero)
setinstancevariable exit reasons:
    (all relevant counters are zero)
opt_aref exit reasons: 
    (all relevant counters are zero)
expandarray exit reasons: 
            splat:      9,974 (99.8%)
    rhs_too_small:         23 ( 0.2%)
opt_getinlinecache exit reasons: 
    miss:         11 (100.0%)
invalidation reasons: 
       constant_ic_fill:      2,055 (58.1%)
          method_lookup:      1,140 (32.2%)
    constant_state_bump:        341 ( 9.6%)
num_send:                 13,804,774
num_send_known_class:        491,792 ( 3.6%)
num_send_polymorphic:      1,804,070 (13.1%)
iseq_stack_too_large:              0
iseq_too_long:                     0
bindings_allocations:            186
bindings_set:                      0
compiled_iseq_count:           9,297
compiled_block_count:         55,713
compiled_branch_count:        90,125
block_next_count:             15,333
defer_count:                  17,270
defer_empty_count:             2,838
freed_iseq_count:              4,058
invalidation_count:            3,536
constant_state_bumps:              0
get_ivar_max_depth:           10,068
inline_code_size:         10,302,980
outlined_code_size:       10,300,948
freed_code_size:                   0
code_region_size:         20,611,072
yjit_alloc_size:          16,436,061
live_context_size:         1,499,008
live_context_count:           53,536
live_page_count:               1,258
freed_page_count:                  0
code_gc_count:                     0
num_gc_obj_refs:              47,455
object_shape_count:            2,452
side_exit_count:             433,049
total_exit_count:          2,187,491
total_insns_count:        89,323,315
vm_insns_count:            7,751,075
yjit_insns_count:         82,005,289
ratio_in_yjit:                 91.3%
avg_len_in_yjit:                37.3
Top-20 most frequent exit ops (100.0% of exits):
               invokesuper:    105,390 (24.3%)
                      send:     98,084 (22.6%)
    opt_send_without_block:     92,015 (21.2%)
      opt_getconstant_path:     53,905 (12.4%)
               invokeblock:     31,108 ( 7.2%)
                  opt_aref:     14,088 ( 3.3%)
                     throw:     10,655 ( 2.5%)
               expandarray:      9,997 ( 2.3%)
             setlocal_WC_0:      8,401 ( 1.9%)
                    opt_eq:      4,991 ( 1.2%)
        getblockparamproxy:      2,271 ( 0.5%)
          putspecialobject:        729 ( 0.2%)
               objtostring:        432 ( 0.1%)
                 opt_nil_p:        313 ( 0.1%)
             definesmethod:        237 ( 0.1%)
                checkmatch:        205 ( 0.0%)
                      once:        104 ( 0.0%)
               opt_empty_p:         30 ( 0.0%)
                     leave:         29 ( 0.0%)
             setblockparam:         25 ( 0.0%)

Rails Bench After

         ***YJIT: Printing YJIT statistics on exit***
method call exit reasons: 
                          block_arg:     64,788 (20.3%)
                        iseq_zsuper:     60,077 (18.9%)
            iseq_has_rest_and_block:     54,470 (17.1%)
                   iseq_arity_error:     30,685 ( 9.6%)
                iseq_ruby2_keywords:     25,058 ( 7.9%)
                     iseq_has_no_kw:     17,298 ( 5.4%)
          args_splat_cfunc_var_args:     16,295 ( 5.1%)
                           kw_splat:     12,997 ( 4.1%)
         iseq_has_rest_and_optional:     10,626 ( 3.3%)
                    iseq_has_kwrest:      7,320 ( 2.3%)
                  klass_megamorphic:      7,068 ( 2.2%)
           iseq_missing_optional_kw:      4,054 ( 1.3%)
               iseq_has_rest_and_kw:      2,183 ( 0.7%)
             args_splat_cfunc_zuper:      2,002 ( 0.6%)
                      iseq_has_post:      1,988 ( 0.6%)
              cfunc_ruby_array_varg:      1,360 ( 0.4%)
                           keywords:        102 ( 0.0%)
    args_splat_cfunc_ruby2_keywords:         62 ( 0.0%)
                    args_splat_ivar:         50 ( 0.0%)
                      zsuper_method:         14 ( 0.0%)
                        send_getter:         12 ( 0.0%)
                args_splat_opt_call:          5 ( 0.0%)
                    ivar_set_method:          2 ( 0.0%)
                  bmethod_block_arg:          2 ( 0.0%)
        splatarray_length_not_equal:          2 ( 0.0%)
invokeblock exit reasons: 
      proc:      2,248 (92.7%)
    symbol:        176 ( 7.3%)
invokesuper exit reasons: 
    me_changed:      4,793 (68.6%)
         block:      2,194 (31.4%)
leave exit reasons: 
        interp_return:  1,754,414 (97.6%)
    start_pc_non_zero:     43,884 ( 2.4%)
         se_interrupt:         31 ( 0.0%)
getblockparamproxy exit reasons: 
    block_param_modified:          3 (100.0%)
getinstancevariable exit reasons:
    (all relevant counters are zero)
setinstancevariable exit reasons:
    (all relevant counters are zero)
opt_aref exit reasons: 
    (all relevant counters are zero)
expandarray exit reasons: 
            splat:      9,973 (99.8%)
    rhs_too_small:         23 ( 0.2%)
opt_getinlinecache exit reasons: 
    miss:         11 (100.0%)
invalidation reasons: 
       constant_ic_fill:      2,055 (58.1%)
          method_lookup:      1,144 (32.3%)
    constant_state_bump:        338 ( 9.6%)
num_send:                 13,818,721
num_send_known_class:        491,790 ( 3.6%)
num_send_polymorphic:      1,818,020 (13.2%)
iseq_stack_too_large:              0
iseq_too_long:                     0
bindings_allocations:            186
bindings_set:                      0
compiled_iseq_count:           9,297
compiled_block_count:         55,693
compiled_branch_count:        90,098
block_next_count:             15,334
defer_count:                  17,268
defer_empty_count:             2,839
freed_iseq_count:              4,058
invalidation_count:            3,537
constant_state_bumps:              0
get_ivar_max_depth:           10,069
inline_code_size:         10,303,984
outlined_code_size:       10,301,888
freed_code_size:                   0
code_region_size:         20,611,072
yjit_alloc_size:          16,437,457
live_context_size:         1,498,560
live_context_count:           53,520
live_page_count:               1,258
freed_page_count:                  0
code_gc_count:                     0
num_gc_obj_refs:              47,443
object_shape_count:            2,452
side_exit_count:             431,055
total_exit_count:          2,185,469
total_insns_count:        89,524,957
vm_insns_count:            7,749,203
yjit_insns_count:         82,206,809
ratio_in_yjit:                 91.3%
avg_len_in_yjit:                37.4
Top-20 most frequent exit ops (100.0% of exits):
               invokesuper:    105,392 (24.4%)
                      send:     98,083 (22.8%)
    opt_send_without_block:     90,019 (20.9%)
      opt_getconstant_path:     53,906 (12.5%)
               invokeblock:     31,108 ( 7.2%)
                  opt_aref:     14,086 ( 3.3%)
                     throw:     10,655 ( 2.5%)
               expandarray:      9,996 ( 2.3%)
             setlocal_WC_0:      8,401 ( 1.9%)
                    opt_eq:      4,990 ( 1.2%)
        getblockparamproxy:      2,271 ( 0.5%)
          putspecialobject:        729 ( 0.2%)
               objtostring:        430 ( 0.1%)
                 opt_nil_p:        313 ( 0.1%)
             definesmethod:        237 ( 0.1%)
                checkmatch:        204 ( 0.0%)
                      once:        104 ( 0.0%)
                     leave:         32 ( 0.0%)
               opt_empty_p:         30 ( 0.0%)
             setblockparam:         25 ( 0.0%)

Liquid Render Before

         ***YJIT: Printing YJIT statistics on exit***
method call exit reasons: 
                    block_arg:      1,470 (60.8%)
                zsuper_method:        832 (34.4%)
        cfunc_ruby_array_varg:         35 ( 1.4%)
            klass_megamorphic:         32 ( 1.3%)
         iseq_has_rest_and_kw:         14 ( 0.6%)
                  send_getter:         12 ( 0.5%)
     iseq_missing_optional_kw:          9 ( 0.4%)
    args_splat_cfunc_var_args:          8 ( 0.3%)
                     kw_splat:          3 ( 0.1%)
      iseq_has_rest_and_block:          1 ( 0.0%)
              ivar_set_method:          1 ( 0.0%)
invokeblock exit reasons: 
      proc:        344 (81.3%)
    symbol:         79 (18.7%)
invokesuper exit reasons: 
    block:         81 (100.0%)
leave exit reasons: 
        interp_return:    275,761 (100.0%)
    start_pc_non_zero:        110 ( 0.0%)
         se_interrupt:          9 ( 0.0%)
getblockparamproxy exit reasons: 
    (all relevant counters are zero)
getinstancevariable exit reasons:
    (all relevant counters are zero)
setinstancevariable exit reasons:
    (all relevant counters are zero)
opt_aref exit reasons: 
    (all relevant counters are zero)
expandarray exit reasons: 
    rhs_too_small:         10 (100.0%)
opt_getinlinecache exit reasons: 
    (all relevant counters are zero)
invalidation reasons: 
       constant_ic_fill:        583 (81.7%)
    constant_state_bump:         91 (12.7%)
          method_lookup:         40 ( 5.6%)
num_send:                  3,024,118
num_send_known_class:        135,743 ( 4.5%)
num_send_polymorphic:        584,808 (19.3%)
iseq_stack_too_large:              0
iseq_too_long:                     0
bindings_allocations:            152
bindings_set:                      0
compiled_iseq_count:           1,689
compiled_block_count:         11,963
compiled_branch_count:        19,756
block_next_count:              4,219
defer_count:                   3,900
defer_empty_count:               773
freed_iseq_count:                560
invalidation_count:              714
constant_state_bumps:              0
get_ivar_max_depth:               10
inline_code_size:          1,998,512
outlined_code_size:        1,995,712
freed_code_size:                   0
code_region_size:          3,997,696
yjit_alloc_size:           5,496,381
live_context_size:           514,248
live_context_count:           18,366
live_page_count:                 244
freed_page_count:                  0
code_gc_count:                     0
num_gc_obj_refs:               7,955
object_shape_count:              770
side_exit_count:              23,050
total_exit_count:            298,811
total_insns_count:        20,332,079
vm_insns_count:            2,298,855
yjit_insns_count:         18,056,274
ratio_in_yjit:                 88.7%
avg_len_in_yjit:                60.3
Top-17 most frequent exit ops (100.0% of exits):
                     throw:     19,105 (82.9%)
                      send:      1,493 ( 6.5%)
    opt_send_without_block:        924 ( 4.0%)
      opt_getconstant_path:        751 ( 3.3%)
               invokeblock:        423 ( 1.8%)
                    opt_eq:         89 ( 0.4%)
                      once:         87 ( 0.4%)
               invokesuper:         82 ( 0.4%)
          putspecialobject:         37 ( 0.2%)
             setlocal_WC_0:         12 ( 0.1%)
        getblockparamproxy:         11 ( 0.0%)
               expandarray:         10 ( 0.0%)
                  opt_aref:         10 ( 0.0%)
                     leave:          9 ( 0.0%)
                opt_length:          3 ( 0.0%)
                checkmatch:          2 ( 0.0%)
                  opt_ltlt:          2 ( 0.0%)

Liquid Render After

         ***YJIT: Printing YJIT statistics on exit***
method call exit reasons: 
                    block_arg:      1,470 (60.8%)
                zsuper_method:        832 (34.4%)
        cfunc_ruby_array_varg:         35 ( 1.4%)
            klass_megamorphic:         32 ( 1.3%)
         iseq_has_rest_and_kw:         14 ( 0.6%)
                  send_getter:         12 ( 0.5%)
     iseq_missing_optional_kw:          9 ( 0.4%)
    args_splat_cfunc_var_args:          8 ( 0.3%)
                     kw_splat:          3 ( 0.1%)
      iseq_has_rest_and_block:          1 ( 0.0%)
              ivar_set_method:          1 ( 0.0%)
invokeblock exit reasons: 
      proc:        344 (81.3%)
    symbol:         79 (18.7%)
invokesuper exit reasons: 
    block:         81 (100.0%)
leave exit reasons: 
        interp_return:    275,783 (100.0%)
    start_pc_non_zero:        110 ( 0.0%)
         se_interrupt:         15 ( 0.0%)
getblockparamproxy exit reasons: 
    (all relevant counters are zero)
getinstancevariable exit reasons:
    (all relevant counters are zero)
setinstancevariable exit reasons:
    (all relevant counters are zero)
opt_aref exit reasons: 
    (all relevant counters are zero)
expandarray exit reasons: 
    rhs_too_small:         10 (100.0%)
opt_getinlinecache exit reasons: 
    (all relevant counters are zero)
invalidation reasons: 
       constant_ic_fill:        583 (81.7%)
    constant_state_bump:         91 (12.7%)
          method_lookup:         40 ( 5.6%)
num_send:                  3,023,933
num_send_known_class:        135,728 ( 4.5%)
num_send_polymorphic:        584,785 (19.3%)
iseq_stack_too_large:              0
iseq_too_long:                     0
bindings_allocations:            152
bindings_set:                      0
compiled_iseq_count:           1,689
compiled_block_count:         11,964
compiled_branch_count:        19,751
block_next_count:              4,220
defer_count:                   3,900
defer_empty_count:               773
freed_iseq_count:                560
invalidation_count:              714
constant_state_bumps:              0
get_ivar_max_depth:               10
inline_code_size:          1,999,512
outlined_code_size:        1,999,216
freed_code_size:                   0
code_region_size:          4,014,080
yjit_alloc_size:           5,497,073
live_context_size:           514,276
live_context_count:           18,367
live_page_count:                 245
freed_page_count:                  0
code_gc_count:                     0
num_gc_obj_refs:               7,956
object_shape_count:              770
side_exit_count:              23,056
total_exit_count:            298,839
total_insns_count:        20,331,889
vm_insns_count:            2,299,558
yjit_insns_count:         18,055,387
ratio_in_yjit:                 88.7%
avg_len_in_yjit:                60.3
Top-16 most frequent exit ops (100.0% of exits):
                     throw:     19,105 (82.9%)
                      send:      1,491 ( 6.5%)
    opt_send_without_block:        928 ( 4.0%)
      opt_getconstant_path:        751 ( 3.3%)
               invokeblock:        423 ( 1.8%)
                    opt_eq:         89 ( 0.4%)
                      once:         87 ( 0.4%)
               invokesuper:         82 ( 0.4%)
          putspecialobject:         37 ( 0.2%)
                     leave:         15 ( 0.1%)
             setlocal_WC_0:         12 ( 0.1%)
        getblockparamproxy:         11 ( 0.0%)
               expandarray:         10 ( 0.0%)
                  opt_aref:         10 ( 0.0%)
                  opt_ltlt:          3 ( 0.0%)
                checkmatch:          2 ( 0.0%)