Merge pull request #4286 from BuckleScript/optimize_array_for_loop

optimize array for loop

Author: bobzhang

jscomp/core/j.ml

@@ -94,7 +94,7 @@ and exception_ident = ident
 
 and for_ident = ident 
 
-and for_direction = Asttypes.direction_flag
+and for_direction = Js_op.direction_flag
 
 and property_map = 
     (property_name * expression) list

jscomp/core/js_dump.ml

@@ -265,6 +265,7 @@ let pp_var_declare cxt f id =
 
 let pp_direction f (direction : J.for_direction) =   
   match direction with
+  | Up
   | Upto -> P.string f L.plus_plus
   | Downto -> P.string f L.minus_minus 
 
@@ -1171,6 +1172,10 @@ and statement_desc top cxt f (s : J.statement_desc) : cxt =
                       let (_,_,right) = Js_op_util.op_prec Le  in
                       P.string f L.le;
                       right
+                    | Up ->  
+                      let (_,_,right) = Js_op_util.op_prec Lt  in
+                      P.string f L.lt;
+                      right
                     | Downto ->
                       let (_,_,right) = Js_op_util.op_prec Ge in
                       P.string f L.ge ;

jscomp/core/js_dump_lit.ml

@@ -81,7 +81,9 @@ let string_cap = "String"
 let fromCharcode = "fromCharCode"
 let eq = "="
 let le = "<="
+let lt = "<"
 let ge = ">="
+let gt = ">"
 let plus_plus = "++" 
 (*  FIXME: use (i = i + 1 | 0) instead  *)
 let minus_minus = "--"

jscomp/core/js_op.ml

@@ -184,6 +184,10 @@ type mutable_flag =
   | Mutable
   | Immutable
   | NA
+type direction_flag = 
+  | Upto
+  | Downto
+  | Up
 
 (* 
     {[

jscomp/core/lam_compile.ml

@@ -954,7 +954,13 @@ and compile_while (predicate : Lam.t) (body : Lam.t) (lambda_cxt : Lam_compile_c
 *)
 
 and compile_for 
-    id start finish direction body (lambda_cxt : Lam_compile_context.t) = 
+    (id : J.for_ident) 
+    (start : Lam.t) 
+    (finish : Lam.t) 
+    (direction : Js_op.direction_flag) 
+    (body : Lam.t)
+    (lambda_cxt : Lam_compile_context.t) 
+    = 
     let new_cxt = {lambda_cxt with continuation = NeedValue Not_tail} in 
     let block =
       match compile_lambda new_cxt start,
@@ -1599,8 +1605,13 @@ and compile_lambda
       compile_staticcatch cur_lam lambda_cxt      
     | Lwhile(p,body) ->
       compile_while p body lambda_cxt
-    | Lfor (id,start,finish,direction,body) ->
-      compile_for id start finish direction body lambda_cxt
+    | Lfor (id,start,finish,direction,body) ->  
+      begin match direction,finish with 
+        | Upto, Lprim {primitive = Psubint ; args = [ new_finish ; Lconst (Const_int 1) ]} ->
+          compile_for id start new_finish Up body lambda_cxt
+        | _ -> 
+          compile_for id start finish (if direction = Upto then Upto else Downto) body lambda_cxt
+      end
     | Lassign(id,lambda) ->
       compile_assign id lambda lambda_cxt
     | Ltrywith(lam,id, catch) ->  (* generate documentation *)

jscomp/test/array_test.js

@@ -18,7 +18,7 @@ function starts_with(xs, prefix, p) {
     return false;
   }
   try {
-    for(var i = 0 ,i_finish = len2 - 1 | 0; i <= i_finish; ++i){
+    for(var i = 0; i < len2; ++i){
       if (!Curry._2(p, Caml_array.caml_array_get(xs, i), Caml_array.caml_array_get(prefix, i))) {
         throw H;
       }

jscomp/test/bdd.js

@@ -331,7 +331,7 @@ function random(param) {
 
 function random_vars(n) {
   var vars = Caml_array.caml_make_vect(n, false);
-  for(var i = 0 ,i_finish = n - 1 | 0; i <= i_finish; ++i){
+  for(var i = 0; i < n; ++i){
     Caml_array.caml_array_set(vars, i, random(undefined));
   }
   return vars;
@@ -353,7 +353,7 @@ function bool_equal(a, b) {
 
 function test_hwb(bdd, vars) {
   var ntrue = 0;
-  for(var i = 0 ,i_finish = vars.length - 1 | 0; i <= i_finish; ++i){
+  for(var i = 0 ,i_finish = vars.length; i < i_finish; ++i){
     if (Caml_array.caml_array_get(vars, i)) {
       ntrue = ntrue + 1 | 0;
     }

jscomp/test/bench.js

@@ -12,7 +12,7 @@ function map(f, a) {
     return [];
   }
   var r = Caml_array.caml_make_vect(l, f$1(a[0]));
-  for(var i = 1 ,i_finish = l - 1 | 0; i <= i_finish; ++i){
+  for(var i = 1; i < l; ++i){
     r[i] = f$1(a[i]);
   }
   return r;
@@ -39,7 +39,7 @@ function init(l, f) {
 function fold_left(f, x, a) {
   var f$1 = Curry.__2(f);
   var r = x;
-  for(var i = 0 ,i_finish = a.length - 1 | 0; i <= i_finish; ++i){
+  for(var i = 0 ,i_finish = a.length; i < i_finish; ++i){
     r = f$1(r, a[i]);
   }
   return r;

jscomp/test/bigarray_test.js

@@ -5,14 +5,14 @@ var Caml_external_polyfill = require("../../lib/js/caml_external_polyfill.js");
 
 function sum(v) {
   var result = 0;
-  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v) - 1 | 0; i <= i_finish; ++i){
+  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v); i < i_finish; ++i){
     result = result + Caml_external_polyfill.resolve("caml_ba_get_1")(v, i) | 0;
   }
 
 }
 
 function init(v) {
-  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v) - 1 | 0; i <= i_finish; ++i){
+  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v); i < i_finish; ++i){
     v[i] = {
       re: Caml_int32.imul(i, i),
       im: Caml_int32.imul(Caml_int32.imul(i, i), i)
@@ -22,14 +22,14 @@ function init(v) {
 }
 
 function init2(v) {
-  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v) - 1 | 0; i <= i_finish; ++i){
+  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v); i < i_finish; ++i){
     v[i] = i;
   }
 
 }
 
 function init3(v) {
-  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v) - 1 | 0; i <= i_finish; ++i){
+  for(var i = 0 ,i_finish = Caml_external_polyfill.resolve("caml_ba_dim_1")(v); i < i_finish; ++i){
     Caml_external_polyfill.resolve("caml_ba_set_1")(v, i, i);
   }
 

jscomp/test/bs_array_test.js

@@ -392,9 +392,9 @@ function makeMatrixExn(sx, sy, init) {
     throw new Error("File \"bs_array_test.ml\", line 109, characters 4-10");
   }
   var res = new Array(sx);
-  for(var x = 0 ,x_finish = sx - 1 | 0; x <= x_finish; ++x){
+  for(var x = 0; x < sx; ++x){
     var initY = new Array(sy);
-    for(var y = 0 ,y_finish = sy - 1 | 0; y <= y_finish; ++y){
+    for(var y = 0; y < sy; ++y){
       initY[y] = init;
     }
     res[x] = initY;