wasm2js: more js optimization (#2050)

* Emit ints as signed, so -1 isn't a big unsigned number.
* x - -c (where c is a constant) is larger than x + c in js (but not wasm)
* +(+x) => +x
* Avoid unnecessary coercions on calls, return, load, etc. - we just need coercions when entering or exiting "wasm" (not internally), and on actual operations that need them.

1 files changed, 30 insertions, 73 deletions

diff --git a/test/wasm2js/float-ops.2asm.js b/test/wasm2js/float-ops.2asm.js
index ca6079c19..4d691213a 100644
--- a/test/wasm2js/float-ops.2asm.js
+++ b/test/wasm2js/float-ops.2asm.js
@@ -167,7 +167,7 @@ function asmFunc(global, env, buffer) {
  
  function $25($0) {
   $0 = Math_fround($0);
-  return +(+$0);
+  return +$0;
  }
  
  function $26($0) {
@@ -212,7 +212,7 @@ function asmFunc(global, env, buffer) {
  
  function $36($0) {
   $0 = $0 | 0;
-  return +(+($0 | 0));
+  return +($0 | 0);
  }
  
  function $37($0) {
@@ -222,7 +222,7 @@ function asmFunc(global, env, buffer) {
  
  function $38($0) {
   $0 = $0 | 0;
-  return +(+($0 >>> 0));
+  return +($0 >>> 0);
  }
  
  function $39($0) {
@@ -358,125 +358,90 @@ function asmFunc(global, env, buffer) {
  }
  
  function legalstub$1($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return +(+Math_fround($1(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1)))));
+  return +$1(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$2($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return +(+Math_fround($2(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1)))));
+  return +$2(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$3($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return +(+Math_fround($3(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1)))));
+  return +$3(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$4($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return +(+Math_fround($4(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1)))));
+  return +$4(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$9($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return $9(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1))) | 0;
+  return $9(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$10($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return $10(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1))) | 0;
+  return $10(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$11($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return $11(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1))) | 0;
+  return $11(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$12($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return $12(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1))) | 0;
+  return $12(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$13($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return $13(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1))) | 0;
+  return $13(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$14($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return $14(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1))) | 0;
+  return $14(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$21($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return +(+Math_fround($21(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1)))));
+  return +$21(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$22($0, $1_1) {
-  $0 = +$0;
-  $1_1 = +$1_1;
-  return +(+Math_fround($22(Math_fround(Math_fround($0)), Math_fround(Math_fround($1_1)))));
+  return +$22(Math_fround($0), Math_fround($1_1));
  }
  
  function legalstub$25($0) {
-  $0 = +$0;
-  return +(+$25(Math_fround(Math_fround($0))));
+  return $25(Math_fround($0));
  }
  
  function legalstub$26($0) {
-  $0 = +$0;
-  return +(+Math_fround($26(+$0)));
+  return +$26($0);
  }
  
  function legalstub$27($0) {
-  $0 = +$0;
-  return +(+Math_fround($27(Math_fround(Math_fround($0)))));
+  return +$27(Math_fround($0));
  }
  
  function legalstub$28($0) {
-  $0 = +$0;
-  return +(+Math_fround($28(Math_fround(Math_fround($0)))));
+  return +$28(Math_fround($0));
  }
  
  function legalstub$31($0) {
-  $0 = +$0;
-  return +(+Math_fround($31(Math_fround(Math_fround($0)))));
+  return +$31(Math_fround($0));
  }
  
  function legalstub$35($0) {
-  $0 = $0 | 0;
-  return +(+Math_fround($35($0 | 0)));
+  return +$35($0);
  }
  
  function legalstub$37($0) {
-  $0 = $0 | 0;
-  return +(+Math_fround($37($0 | 0)));
+  return +$37($0);
  }
  
  function legalstub$39($0) {
-  $0 = +$0;
-  return $39(Math_fround(Math_fround($0))) | 0;
+  return $39(Math_fround($0));
  }
  
  function legalstub$41($0) {
-  $0 = +$0;
-  return $41(Math_fround(Math_fround($0))) | 0;
+  return $41(Math_fround($0));
  }
  
  function legalstub$43($0, $1_1) {
-  $0 = $0 | 0;
-  $1_1 = $1_1 | 0;
   var i64toi32_i32$2 = 0, i64toi32_i32$0 = 0, i64toi32_i32$1 = 0, i64toi32_i32$4 = 0, i64toi32_i32$3 = 0, $10_1 = 0, $3_1 = 0, $3$hi = 0, $6$hi = 0;
   i64toi32_i32$0 = 0;
   $3_1 = $0;
@@ -503,12 +468,10 @@ function asmFunc(global, env, buffer) {
   i64toi32_i32$2 = $6$hi;
   i64toi32_i32$3 = $10_1;
   i64toi32_i32$2 = i64toi32_i32$1 | i64toi32_i32$2;
-  return +(+Math_fround($43(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2 | 0)));
+  return +$43(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2);
  }
  
  function legalstub$44($0, $1_1) {
-  $0 = $0 | 0;
-  $1_1 = $1_1 | 0;
   var i64toi32_i32$2 = 0, i64toi32_i32$0 = 0, i64toi32_i32$1 = 0, i64toi32_i32$4 = 0, i64toi32_i32$3 = 0, $10_1 = 0, $3_1 = 0, $3$hi = 0, $6$hi = 0;
   i64toi32_i32$0 = 0;
   $3_1 = $0;
@@ -535,12 +498,10 @@ function asmFunc(global, env, buffer) {
   i64toi32_i32$2 = $6$hi;
   i64toi32_i32$3 = $10_1;
   i64toi32_i32$2 = i64toi32_i32$1 | i64toi32_i32$2;
-  return +(+$44(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2 | 0));
+  return $44(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2);
  }
  
  function legalstub$45($0, $1_1) {
-  $0 = $0 | 0;
-  $1_1 = $1_1 | 0;
   var i64toi32_i32$2 = 0, i64toi32_i32$0 = 0, i64toi32_i32$1 = 0, i64toi32_i32$4 = 0, i64toi32_i32$3 = 0, $10_1 = 0, $3_1 = 0, $3$hi = 0, $6$hi = 0;
   i64toi32_i32$0 = 0;
   $3_1 = $0;
@@ -567,12 +528,10 @@ function asmFunc(global, env, buffer) {
   i64toi32_i32$2 = $6$hi;
   i64toi32_i32$3 = $10_1;
   i64toi32_i32$2 = i64toi32_i32$1 | i64toi32_i32$2;
-  return +(+Math_fround($45(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2 | 0)));
+  return +$45(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2);
  }
  
  function legalstub$46($0, $1_1) {
-  $0 = $0 | 0;
-  $1_1 = $1_1 | 0;
   var i64toi32_i32$2 = 0, i64toi32_i32$0 = 0, i64toi32_i32$1 = 0, i64toi32_i32$4 = 0, i64toi32_i32$3 = 0, $10_1 = 0, $3_1 = 0, $3$hi = 0, $6$hi = 0;
   i64toi32_i32$0 = 0;
   $3_1 = $0;
@@ -599,17 +558,15 @@ function asmFunc(global, env, buffer) {
   i64toi32_i32$2 = $6$hi;
   i64toi32_i32$3 = $10_1;
   i64toi32_i32$2 = i64toi32_i32$1 | i64toi32_i32$2;
-  return +(+$46(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2 | 0));
+  return $46(i64toi32_i32$0 | i64toi32_i32$3, i64toi32_i32$2);
  }
  
  function legalstub$47($0) {
-  $0 = +$0;
-  return $47(Math_fround(Math_fround($0))) | 0;
+  return $47(Math_fround($0));
  }
  
  function legalstub$49($0) {
-  $0 = +$0;
-  return $49(Math_fround(Math_fround($0))) | 0;
+  return $49(Math_fround($0));
  }
  
  var FUNCTION_TABLE = [];