[wasm2js] Use native JavaScript Math.trunc (#3329)

5 files changed, 9 insertions, 48 deletions

diff --git a/src/asmjs/shared-constants.cpp b/src/asmjs/shared-constants.cpp
index 2cb7d901c..20b148155 100644
--- a/src/asmjs/shared-constants.cpp
+++ b/src/asmjs/shared-constants.cpp
@@ -52,6 +52,7 @@ cashew::IString I32U_REM("i32u-rem");
 cashew::IString ABS("abs");
 cashew::IString FLOOR("floor");
 cashew::IString CEIL("ceil");
+cashew::IString TRUNC("trunc");
 cashew::IString SQRT("sqrt");
 cashew::IString POW("pow");
 cashew::IString I32_TEMP("asm2wasm_i32_temp");
@@ -86,8 +87,6 @@ cashew::IString WASM_FETCH_HIGH_BITS("__wasm_fetch_high_bits");
 cashew::IString INT64_TO_32_HIGH_BITS("i64toi32_i32$HIGH_BITS");
 cashew::IString WASM_NEAREST_F32("__wasm_nearest_f32");
 cashew::IString WASM_NEAREST_F64("__wasm_nearest_f64");
-cashew::IString WASM_TRUNC_F32("__wasm_trunc_f32");
-cashew::IString WASM_TRUNC_F64("__wasm_trunc_f64");
 cashew::IString WASM_I64_MUL("__wasm_i64_mul");
 cashew::IString WASM_I64_SDIV("__wasm_i64_sdiv");
 cashew::IString WASM_I64_UDIV("__wasm_i64_udiv");
diff --git a/src/asmjs/shared-constants.h b/src/asmjs/shared-constants.h
index d458db684..20edacb7e 100644
--- a/src/asmjs/shared-constants.h
+++ b/src/asmjs/shared-constants.h
@@ -55,6 +55,7 @@ extern cashew::IString I32U_REM;
 extern cashew::IString ABS;
 extern cashew::IString FLOOR;
 extern cashew::IString CEIL;
+extern cashew::IString TRUNC;
 extern cashew::IString SQRT;
 extern cashew::IString POW;
 extern cashew::IString I32_TEMP;
@@ -66,8 +67,8 @@ extern cashew::IString STACK_MAX;
 extern cashew::IString INSTRUMENT;
 extern cashew::IString MATH_IMUL;
 extern cashew::IString MATH_ABS;
-extern cashew::IString MATH_CEIL;
 extern cashew::IString MATH_CLZ32;
+extern cashew::IString MATH_CEIL;
 extern cashew::IString MATH_FLOOR;
 extern cashew::IString MATH_TRUNC;
 extern cashew::IString MATH_SQRT;
@@ -89,8 +90,6 @@ extern cashew::IString WASM_FETCH_HIGH_BITS;
 extern cashew::IString INT64_TO_32_HIGH_BITS;
 extern cashew::IString WASM_NEAREST_F32;
 extern cashew::IString WASM_NEAREST_F64;
-extern cashew::IString WASM_TRUNC_F32;
-extern cashew::IString WASM_TRUNC_F64;
 extern cashew::IString WASM_I64_MUL;
 extern cashew::IString WASM_I64_SDIV;
 extern cashew::IString WASM_I64_UDIV;
diff --git a/src/passes/RemoveNonJSOps.cpp b/src/passes/RemoveNonJSOps.cpp
index abd3526c4..08e6e6482 100644
--- a/src/passes/RemoveNonJSOps.cpp
+++ b/src/passes/RemoveNonJSOps.cpp
@@ -299,13 +299,6 @@ struct RemoveNonJSOpsPass : public WalkerPass<PostWalker<RemoveNonJSOpsPass>> {
         functionCall = WASM_NEAREST_F64;
         break;
 
-      case TruncFloat32:
-        functionCall = WASM_TRUNC_F32;
-        break;
-      case TruncFloat64:
-        functionCall = WASM_TRUNC_F64;
-        break;
-
       case PopcntInt64:
         functionCall = WASM_POPCNT64;
         break;
diff --git a/src/passes/wasm-intrinsics.wat b/src/passes/wasm-intrinsics.wat
index 17bf0d649..185bef961 100644
--- a/src/passes/wasm-intrinsics.wat
+++ b/src/passes/wasm-intrinsics.wat
@@ -26,8 +26,6 @@
  (export "__wasm_i64_srem" (func $__wasm_i64_srem))
  (export "__wasm_i64_urem" (func $__wasm_i64_urem))
  (export "__wasm_i64_mul" (func $__wasm_i64_mul))
- (export "__wasm_trunc_f32" (func $__wasm_trunc_f32))
- (export "__wasm_trunc_f64" (func $__wasm_trunc_f64))
  (export "__wasm_ctz_i32" (func $__wasm_ctz_i32))
  (export "__wasm_ctz_i64" (func $__wasm_ctz_i64))
  (export "__wasm_rotl_i32" (func $__wasm_rotl_i32))
@@ -144,38 +142,6 @@
    (local.get $var$1)
   )
  )
- ;; lowering of the f32.trunc instruction, rounds to the nearest integer,
- ;; towards zero
- (func $__wasm_trunc_f32 (; 5 ;) (type $1) (param $var$0 f32) (result f32)
-  (select
-   (f32.ceil
-    (local.get $var$0)
-   )
-   (f32.floor
-    (local.get $var$0)
-   )
-   (f32.lt
-    (local.get $var$0)
-    (f32.const 0)
-   )
-  )
- )
- ;; lowering of the f64.trunc instruction, rounds to the nearest integer,
- ;; towards zero
- (func $__wasm_trunc_f64 (; 6 ;) (type $2) (param $var$0 f64) (result f64)
-  (select
-   (f64.ceil
-    (local.get $var$0)
-   )
-   (f64.floor
-    (local.get $var$0)
-   )
-   (f64.lt
-    (local.get $var$0)
-    (f64.const 0)
-   )
-  )
- )
  ;; lowering of the i32.ctz instruction, counting the number of zeros in $var$0
  (func $__wasm_ctz_i32 (; 7 ;) (type $3) (param $var$0 i32) (result i32)
   (if
diff --git a/src/wasm2js.h b/src/wasm2js.h
index bdaa2f9f7..b31886329 100644
--- a/src/wasm2js.h
+++ b/src/wasm2js.h
@@ -519,6 +519,7 @@ void Wasm2JSBuilder::addBasics(Ref ast, Module* wasm) {
   addMath(MATH_MAX, MAX);
   addMath(MATH_FLOOR, FLOOR);
   addMath(MATH_CEIL, CEIL);
+  addMath(MATH_TRUNC, TRUNC);
   addMath(MATH_SQRT, SQRT);
   // abort function
   Ref abortVar = ValueBuilder::makeVar();
@@ -1613,6 +1614,11 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
               ret = ValueBuilder::makeCall(
                 MATH_FLOOR, visit(curr->value, EXPRESSION_RESULT));
               break;
+            case TruncFloat32:
+            case TruncFloat64:
+              ret = ValueBuilder::makeCall(
+                MATH_TRUNC, visit(curr->value, EXPRESSION_RESULT));
+              break;
             case SqrtFloat32:
             case SqrtFloat64:
               ret = ValueBuilder::makeCall(
@@ -1666,8 +1672,6 @@ Ref Wasm2JSBuilder::processFunctionBody(Module* m,
             // TODO: more complex unary conversions
             case NearestFloat32:
             case NearestFloat64:
-            case TruncFloat32:
-            case TruncFloat64:
               WASM_UNREACHABLE(
                 "operation should have been removed in previous passes");