Add a specialized instruction for .nil? calls

This commit adds a specialized instruction for called to `.nil?`. It is about 27% faster than master in the case where the object is nil or not nil. In the case where an object implements `nil?`, I think it may be slightly slower. Here is a benchmark: ```ruby require "benchmark/ips" class Niller def nil?; true; end end not_nil = Object.new xnil = nil niller = Niller.new Benchmark.ips do |x| x.report("nil?") { xnil.nil? } x.report("not nil") { not_nil.nil? } x.report("niller") { niller.nil? } end ``` On Ruby master: ``` [aaron@TC ~/g/ruby (master)]$ ./ruby compil.rb Warming up -------------------------------------- nil? 429.195k i/100ms not nil 437.889k i/100ms niller 437.935k i/100ms Calculating ------------------------------------- nil? 20.166M (± 8.1%) i/s - 100.002M in 5.002794s not nil 20.046M (± 7.6%) i/s - 99.839M in 5.020086s niller 22.467M (± 6.1%) i/s - 112.111M in 5.013817s [aaron@TC ~/g/ruby (master)]$ ./ruby compil.rb Warming up -------------------------------------- nil? 449.660k i/100ms not nil 433.836k i/100ms niller 443.073k i/100ms Calculating ------------------------------------- nil? 19.997M (± 8.8%) i/s - 99.375M in 5.020458s not nil 20.529M (± 7.0%) i/s - 102.385M in 5.020689s niller 21.796M (± 8.0%) i/s - 108.110M in 5.002300s [aaron@TC ~/g/ruby (master)]$ ./ruby compil.rb Warming up -------------------------------------- nil? 402.119k i/100ms not nil 438.968k i/100ms niller 398.226k i/100ms Calculating ------------------------------------- nil? 20.050M (±12.2%) i/s - 98.519M in 5.008817s not nil 20.614M (± 8.0%) i/s - 102.280M in 5.004531s niller 22.223M (± 8.8%) i/s - 110.309M in 5.013106s ``` On this branch: ``` [aaron@TC ~/g/ruby (specialized-nilp)]$ ./ruby compil.rb Warming up -------------------------------------- nil? 468.371k i/100ms not nil 456.517k i/100ms niller 454.981k i/100ms Calculating ------------------------------------- nil? 27.849M (± 7.8%) i/s - 138.169M in 5.001730s not nil 26.417M (± 8.7%) i/s - 131.020M in 5.011674s niller 21.561M (± 7.5%) i/s - 107.376M in 5.018113s [aaron@TC ~/g/ruby (specialized-nilp)]$ ./ruby compil.rb Warming up -------------------------------------- nil? 477.259k i/100ms not nil 428.712k i/100ms niller 446.109k i/100ms Calculating ------------------------------------- nil? 28.071M (± 7.3%) i/s - 139.837M in 5.016590s not nil 25.789M (±12.9%) i/s - 126.470M in 5.011144s niller 20.002M (±12.2%) i/s - 98.144M in 5.001737s [aaron@TC ~/g/ruby (specialized-nilp)]$ ./ruby compil.rb Warming up -------------------------------------- nil? 467.676k i/100ms not nil 445.791k i/100ms niller 415.024k i/100ms Calculating ------------------------------------- nil? 26.907M (± 8.0%) i/s - 133.755M in 5.013915s not nil 25.319M (± 7.9%) i/s - 125.713M in 5.007758s niller 19.569M (±11.8%) i/s - 96.286M in 5.008533s ``` Co-Authored-By: Ashe Connor <[email protected]>
github · tenderlove · Mar 14, 2019 · Mar 18, 2019 · Dec 12, 2018 · Mar 18, 2019
commit f5adc780ef510e5cb9486dd777adaa102826b536
diff --git a/benchmark/nil_p.yml b/benchmark/nil_p.yml
@@ -0,0 +1,9 @@
+prelude: |
+  class Niller; def nil?; true; end; end
+  xnil, notnil = nil, Object.new
+  niller = Niller.new
+benchmark:
+  - xnil.nil?
+  - notnil.nil?
+  - niller.nil?
+loop_count: 10000000
diff --git a/compile.c b/compile.c
@@ -3255,6 +3255,7 @@ iseq_specialized_instruction(rb_iseq_t *iseq, INSN *iobj)
 		  case idLength: SP_INSN(length); return COMPILE_OK;
 		  case idSize:	 SP_INSN(size);	  return COMPILE_OK;
 		  case idEmptyP: SP_INSN(empty_p);return COMPILE_OK;
+		  case idNilP:   SP_INSN(nil_p);  return COMPILE_OK;
 		  case idSucc:	 SP_INSN(succ);	  return COMPILE_OK;
 		  case idNot:	 SP_INSN(not);	  return COMPILE_OK;
 		}

diff --git a/defs/id.def b/defs/id.def
@@ -3,6 +3,7 @@ firstline, predefined = __LINE__+1, %[\
   max
   min
   freeze
+  nil?
   inspect
   intern
   object_id

diff --git a/insns.def b/insns.def
@@ -808,6 +808,20 @@ opt_str_freeze
     }
 }
 
+/* optimized nil? */
+DEFINE_INSN
+opt_nil_p
+(CALL_INFO ci, CALL_CACHE cc)
+(VALUE recv)
+(VALUE val)
+{
+    val = vm_opt_nil_p(ci, cc, recv);
+
+    if (val == Qundef) {
+        CALL_SIMPLE_METHOD();
+    }
+}
+
 DEFINE_INSN
 opt_str_uminus
 (VALUE str, CALL_INFO ci, CALL_CACHE cc)

diff --git a/object.c b/object.c
@@ -1687,7 +1687,7 @@ rb_true(VALUE obj)
  */
 
 
-static VALUE
+VALUE
 rb_false(VALUE obj)
 {
     return Qfalse;

diff --git a/vm.c b/vm.c
@@ -1656,6 +1656,7 @@ vm_init_redefined_flag(void)
     OP(Call, CALL), (C(Proc));
     OP(And, AND), (C(Integer));
     OP(Or, OR), (C(Integer));
+    OP(NilP, NIL_P), (C(NilClass));
 #undef C
 #undef OP
 }

diff --git a/vm_core.h b/vm_core.h
@@ -550,6 +550,7 @@ enum ruby_basic_operators {
     BOP_LENGTH,
     BOP_SIZE,
     BOP_EMPTY_P,
+    BOP_NIL_P,
     BOP_SUCC,
     BOP_GT,
     BOP_GE,

diff --git a/vm_insnhelper.c b/vm_insnhelper.c
@@ -4228,6 +4228,26 @@ vm_opt_empty_p(VALUE recv)
     }
 }
 
+VALUE rb_false(VALUE obj);
+
+static VALUE
+vm_opt_nil_p(CALL_INFO ci, CALL_CACHE cc, VALUE recv)
+{
+    if (recv == Qnil) {
+        if (BASIC_OP_UNREDEFINED_P(BOP_NIL_P, NIL_REDEFINED_OP_FLAG)) {
+            return Qtrue;
+        } else {
+            return Qundef;
+        }
+    } else {
+        if (vm_method_cfunc_is(ci, cc, recv, rb_false)) {
+            return Qfalse;
+        } else {
+            return Qundef;
+        }
+    }
+}
+
 static VALUE
 fix_succ(VALUE x)
 {
-Original file line number
+Diff line change
@@ Expand Up / @@ -3,6 +3,7 @@ firstline, predefined = __LINE__+1, %[\ @@
       max
       min
       freeze
+      nil?
       inspect
       intern
       object_id
@@ Expand Down @@