wasm2js: Fix a bug with adjacent reinterprets (#2964)

i64 reinterprets were lowered in the i64 pass, and i32s at the very end, in
wasm2js itself. This could break since in between the i64 pass and wasm2js
we run optimizations, and the optimizer was not aware of what we lower
the i32 reinterprets to - calls to use scratch memory. Those calls have a
side effect of altering scratch memory. The optimizer just saw an i32
reinterpret, and moved it across the i64 reinterpret's scratch memory calls.

This makes 32-bit reinterprets use separate scratch memory from 64-bit ones,
which means they can never interfere with each other.

18 files changed, 220 insertions, 80 deletions

diff --git a/test/wasm2js/atomics_32.2asm.js b/test/wasm2js/atomics_32.2asm.js
index 21f280e4b..bbc599423 100644
--- a/test/wasm2js/atomics_32.2asm.js
+++ b/test/wasm2js/atomics_32.2asm.js
@@ -1,6 +1,6 @@
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
diff --git a/test/wasm2js/atomics_32.2asm.js.opt b/test/wasm2js/atomics_32.2asm.js.opt
index f662c0ad2..d3b9cd1bb 100644
--- a/test/wasm2js/atomics_32.2asm.js.opt
+++ b/test/wasm2js/atomics_32.2asm.js.opt
@@ -1,6 +1,6 @@
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
diff --git a/test/wasm2js/bulk-memory.2asm.js b/test/wasm2js/bulk-memory.2asm.js
index cea852c98..379f919fa 100644
--- a/test/wasm2js/bulk-memory.2asm.js
+++ b/test/wasm2js/bulk-memory.2asm.js
@@ -30,7 +30,7 @@ var memasmFunc = new ArrayBuffer(65536);
 var retasmFunc = asmFunc({Math,Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,Float32Array,Float64Array,NaN,Infinity}, {abort:function() { throw new Error('abort'); }},memasmFunc);
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -115,7 +115,7 @@ export var fill = retasmFunc.fill;
 export var load8_u = retasmFunc.load8_u;
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -196,7 +196,7 @@ export var copy = retasmFunc.copy;
 export var load8_u = retasmFunc.load8_u;
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -301,7 +301,7 @@ export var init = retasmFunc.init;
 export var load8_u = retasmFunc.load8_u;
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
diff --git a/test/wasm2js/bulk-memory.2asm.js.opt b/test/wasm2js/bulk-memory.2asm.js.opt
index 620a7bbc7..a4da19a5d 100644
--- a/test/wasm2js/bulk-memory.2asm.js.opt
+++ b/test/wasm2js/bulk-memory.2asm.js.opt
@@ -30,7 +30,7 @@ var memasmFunc = new ArrayBuffer(65536);
 var retasmFunc = asmFunc({Math,Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,Float32Array,Float64Array,NaN,Infinity}, {abort:function() { throw new Error('abort'); }},memasmFunc);
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -115,7 +115,7 @@ export var fill = retasmFunc.fill;
 export var load8_u = retasmFunc.load8_u;
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -196,7 +196,7 @@ export var copy = retasmFunc.copy;
 export var load8_u = retasmFunc.load8_u;
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
diff --git a/test/wasm2js/conversions-modified.2asm.js b/test/wasm2js/conversions-modified.2asm.js
index 693c287fd..4829bb49f 100644
--- a/test/wasm2js/conversions-modified.2asm.js
+++ b/test/wasm2js/conversions-modified.2asm.js
@@ -1,7 +1,7 @@
 import { setTempRet0 } from 'env';
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -23,11 +23,11 @@ import { setTempRet0 } from 'env';
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
 function asmFunc(global, env, buffer) {
@@ -240,7 +240,7 @@ function asmFunc(global, env, buffer) {
  
  function $21(x) {
   x = x | 0;
-  return Math_fround((wasm2js_scratch_store_i32(0, x), wasm2js_scratch_load_f32()));
+  return Math_fround((wasm2js_scratch_store_i32(2, x), wasm2js_scratch_load_f32()));
  }
  
  function $22(x, x$hi) {
@@ -255,7 +255,7 @@ function asmFunc(global, env, buffer) {
  
  function $23(x) {
   x = Math_fround(x);
-  return (wasm2js_scratch_store_f32(x), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(x), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $24(x) {
diff --git a/test/wasm2js/conversions-modified.2asm.js.opt b/test/wasm2js/conversions-modified.2asm.js.opt
index b30a95a8e..5efd1966d 100644
--- a/test/wasm2js/conversions-modified.2asm.js.opt
+++ b/test/wasm2js/conversions-modified.2asm.js.opt
@@ -1,7 +1,7 @@
 import { setTempRet0 } from 'env';
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -23,11 +23,11 @@ import { setTempRet0 } from 'env';
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
 function asmFunc(global, env, buffer) {
@@ -117,12 +117,12 @@ function asmFunc(global, env, buffer) {
  
  function $21($0) {
   $0 = $0 | 0;
-  return Math_fround((wasm2js_scratch_store_i32(0, $0), wasm2js_scratch_load_f32()));
+  return Math_fround((wasm2js_scratch_store_i32(2, $0), wasm2js_scratch_load_f32()));
  }
  
  function $23($0) {
   $0 = Math_fround($0);
-  return (wasm2js_scratch_store_f32($0), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32($0), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function legalstub$0($0) {
diff --git a/test/wasm2js/endianness.2asm.js b/test/wasm2js/endianness.2asm.js
index 2146a9840..171af7d6c 100644
--- a/test/wasm2js/endianness.2asm.js
+++ b/test/wasm2js/endianness.2asm.js
@@ -1,7 +1,7 @@
 import { setTempRet0 } from 'env';
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -23,11 +23,11 @@ import { setTempRet0 } from 'env';
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
 function asmFunc(global, env, buffer) {
@@ -209,7 +209,7 @@ function asmFunc(global, env, buffer) {
  
  function $14(value) {
   value = Math_fround(value);
-  i32_store_little(0 | 0, (wasm2js_scratch_store_f32(value), wasm2js_scratch_load_i32(0)) | 0);
+  i32_store_little(0 | 0, (wasm2js_scratch_store_f32(value), wasm2js_scratch_load_i32(2)) | 0);
   return Math_fround(Math_fround(HEAPF32[0 >> 2]));
  }
  
@@ -275,7 +275,7 @@ function asmFunc(global, env, buffer) {
  function $21(value) {
   value = Math_fround(value);
   HEAPF32[0 >> 2] = value;
-  return Math_fround((wasm2js_scratch_store_i32(0, i32_load_little(0 | 0) | 0), wasm2js_scratch_load_f32()));
+  return Math_fround((wasm2js_scratch_store_i32(2, i32_load_little(0 | 0) | 0), wasm2js_scratch_load_f32()));
  }
  
  function $22(value) {
diff --git a/test/wasm2js/float_literals-modified.2asm.js b/test/wasm2js/float_literals-modified.2asm.js
index d03cbf0b9..d75781a88 100644
--- a/test/wasm2js/float_literals-modified.2asm.js
+++ b/test/wasm2js/float_literals-modified.2asm.js
@@ -1,7 +1,7 @@
 import { setTempRet0 } from 'env';
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -15,7 +15,7 @@ import { setTempRet0 } from 'env';
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
 function asmFunc(global, env, buffer) {
@@ -42,123 +42,123 @@ function asmFunc(global, env, buffer) {
  var setTempRet0 = env.setTempRet0;
  var i64toi32_i32$HIGH_BITS = 0;
  function $0() {
-  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $1() {
-  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $2() {
-  return (wasm2js_scratch_store_f32(Math_fround(-nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(-nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $3() {
-  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $4() {
-  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $5() {
-  return (wasm2js_scratch_store_f32(Math_fround(-nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(-nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $6() {
-  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $7() {
-  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $8() {
-  return (wasm2js_scratch_store_f32(Math_fround(-nan)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(-nan)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $9() {
-  return (wasm2js_scratch_store_f32(Math_fround(infinity)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(infinity)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $10() {
-  return (wasm2js_scratch_store_f32(Math_fround(infinity)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(infinity)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $11() {
-  return (wasm2js_scratch_store_f32(Math_fround(-infinity)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(-infinity)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $12() {
-  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $13() {
-  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $14() {
-  return (wasm2js_scratch_store_f32(Math_fround(-0.0)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(-0.0)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $15() {
-  return (wasm2js_scratch_store_f32(Math_fround(6.2831854820251465)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(6.2831854820251465)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $16() {
-  return (wasm2js_scratch_store_f32(Math_fround(1.401298464324817e-45)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1.401298464324817e-45)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $17() {
-  return (wasm2js_scratch_store_f32(Math_fround(1.1754943508222875e-38)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1.1754943508222875e-38)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $18() {
-  return (wasm2js_scratch_store_f32(Math_fround(3402823466385288598117041.0e14)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(3402823466385288598117041.0e14)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $19() {
-  return (wasm2js_scratch_store_f32(Math_fround(1.1754942106924411e-38)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1.1754942106924411e-38)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $20() {
-  return (wasm2js_scratch_store_f32(Math_fround(1024.0)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1024.0)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $21() {
-  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $22() {
-  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $23() {
-  return (wasm2js_scratch_store_f32(Math_fround(-0.0)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(-0.0)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $24() {
-  return (wasm2js_scratch_store_f32(Math_fround(6.2831854820251465)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(6.2831854820251465)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $25() {
-  return (wasm2js_scratch_store_f32(Math_fround(1.401298464324817e-45)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1.401298464324817e-45)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $26() {
-  return (wasm2js_scratch_store_f32(Math_fround(1.1754943508222875e-38)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1.1754943508222875e-38)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $27() {
-  return (wasm2js_scratch_store_f32(Math_fround(1.1754942106924411e-38)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1.1754942106924411e-38)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $28() {
-  return (wasm2js_scratch_store_f32(Math_fround(3402823466385288598117041.0e14)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(3402823466385288598117041.0e14)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $29() {
-  return (wasm2js_scratch_store_f32(Math_fround(1.0e10)), wasm2js_scratch_load_i32(0)) | 0;
+  return (wasm2js_scratch_store_f32(Math_fround(1.0e10)), wasm2js_scratch_load_i32(2)) | 0;
  }
  
  function $30() {
diff --git a/test/wasm2js/float_literals-modified.2asm.js.opt b/test/wasm2js/float_literals-modified.2asm.js.opt
index d7aaa2a0d..b055b21f4 100644
--- a/test/wasm2js/float_literals-modified.2asm.js.opt
+++ b/test/wasm2js/float_literals-modified.2asm.js.opt
@@ -1,7 +1,7 @@
 import { setTempRet0 } from 'env';
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
diff --git a/test/wasm2js/float_misc.2asm.js b/test/wasm2js/float_misc.2asm.js
index 8c5b7b0a3..f5b768e61 100644
--- a/test/wasm2js/float_misc.2asm.js
+++ b/test/wasm2js/float_misc.2asm.js
@@ -1,6 +1,6 @@
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -22,11 +22,11 @@
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
 function asmFunc(global, env, buffer) {
@@ -92,7 +92,7 @@ function asmFunc(global, env, buffer) {
  function $7(x, y) {
   x = Math_fround(x);
   y = Math_fround(y);
-  return Math_fround((wasm2js_scratch_store_i32(0, (wasm2js_scratch_store_f32(x), wasm2js_scratch_load_i32(0)) & 2147483647 | 0 | ((wasm2js_scratch_store_f32(y), wasm2js_scratch_load_i32(0)) & -2147483648 | 0) | 0), wasm2js_scratch_load_f32()));
+  return Math_fround((wasm2js_scratch_store_i32(2, (wasm2js_scratch_store_f32(x), wasm2js_scratch_load_i32(2)) & 2147483647 | 0 | ((wasm2js_scratch_store_f32(y), wasm2js_scratch_load_i32(2)) & -2147483648 | 0) | 0), wasm2js_scratch_load_f32()));
  }
  
  function $8(x) {
diff --git a/test/wasm2js/left-to-right.2asm.js b/test/wasm2js/left-to-right.2asm.js
index 5a2826c59..f5f19a1cd 100644
--- a/test/wasm2js/left-to-right.2asm.js
+++ b/test/wasm2js/left-to-right.2asm.js
@@ -1,6 +1,6 @@
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -22,7 +22,7 @@
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
 function asmFunc(global, env, buffer) {
@@ -1019,7 +1019,7 @@ function asmFunc(global, env, buffer) {
  
  function $98() {
   reset();
-  (wasm2js_scratch_store_f32(Math_fround(f32_left())), wasm2js_scratch_load_i32(0)) & 2147483647 | 0 | ((wasm2js_scratch_store_f32(Math_fround(f32_right())), wasm2js_scratch_load_i32(0)) & -2147483648 | 0) | 0;
+  (wasm2js_scratch_store_f32(Math_fround(f32_left())), wasm2js_scratch_load_i32(2)) & 2147483647 | 0 | ((wasm2js_scratch_store_f32(Math_fround(f32_right())), wasm2js_scratch_load_i32(2)) & -2147483648 | 0) | 0;
   return get() | 0 | 0;
  }
  
diff --git a/test/wasm2js/reinterpret.2asm.js b/test/wasm2js/reinterpret.2asm.js
index 64e9161e0..e237552df 100644
--- a/test/wasm2js/reinterpret.2asm.js
+++ b/test/wasm2js/reinterpret.2asm.js
@@ -1,6 +1,6 @@
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -22,11 +22,11 @@
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
 function asmFunc(global, env, buffer) {
@@ -52,7 +52,7 @@ function asmFunc(global, env, buffer) {
  var infinity = global.Infinity;
  function $1($0) {
   $0 = $0 | 0;
-  return ((wasm2js_scratch_store_f32((wasm2js_scratch_store_i32(0, $0), wasm2js_scratch_load_f32())), wasm2js_scratch_load_i32(0)) | 0) == ($0 | 0) | 0;
+  return ((wasm2js_scratch_store_f32((wasm2js_scratch_store_i32(2, $0), wasm2js_scratch_load_f32())), wasm2js_scratch_load_i32(2)) | 0) == ($0 | 0) | 0;
  }
  
  function $2($0, $0$hi) {
diff --git a/test/wasm2js/reinterpret.2asm.js.opt b/test/wasm2js/reinterpret.2asm.js.opt
index 0a8408ff2..5015533ba 100644
--- a/test/wasm2js/reinterpret.2asm.js.opt
+++ b/test/wasm2js/reinterpret.2asm.js.opt
@@ -1,6 +1,6 @@
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -22,11 +22,11 @@
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
 function asmFunc(global, env, buffer) {
@@ -52,7 +52,7 @@ function asmFunc(global, env, buffer) {
  var infinity = global.Infinity;
  function $1($0) {
   $0 = $0 | 0;
-  return ((wasm2js_scratch_store_f32((wasm2js_scratch_store_i32(0, $0), wasm2js_scratch_load_f32())), wasm2js_scratch_load_i32(0)) | 0) == ($0 | 0) | 0;
+  return ((wasm2js_scratch_store_f32((wasm2js_scratch_store_i32(2, $0), wasm2js_scratch_load_f32())), wasm2js_scratch_load_i32(2)) | 0) == ($0 | 0) | 0;
  }
  
  function $2($0, $1_1) {
diff --git a/test/wasm2js/reinterpret_scratch.2asm.js b/test/wasm2js/reinterpret_scratch.2asm.js
new file mode 100644
index 000000000..51c4565f5
--- /dev/null
+++ b/test/wasm2js/reinterpret_scratch.2asm.js
@@ -0,0 +1,64 @@
+
+
+  var scratchBuffer = new ArrayBuffer(16);
+  var i32ScratchView = new Int32Array(scratchBuffer);
+  var f32ScratchView = new Float32Array(scratchBuffer);
+  var f64ScratchView = new Float64Array(scratchBuffer);
+  
+  function wasm2js_scratch_load_i32(index) {
+    return i32ScratchView[index];
+  }
+      
+  function wasm2js_scratch_store_f64(value) {
+    f64ScratchView[0] = value;
+  }
+      
+  function wasm2js_scratch_store_f32(value) {
+    f32ScratchView[2] = value;
+  }
+      
+function asmFunc(global, env, buffer) {
+ var HEAP8 = new global.Int8Array(buffer);
+ var HEAP16 = new global.Int16Array(buffer);
+ var HEAP32 = new global.Int32Array(buffer);
+ var HEAPU8 = new global.Uint8Array(buffer);
+ var HEAPU16 = new global.Uint16Array(buffer);
+ var HEAPU32 = new global.Uint32Array(buffer);
+ var HEAPF32 = new global.Float32Array(buffer);
+ var HEAPF64 = new global.Float64Array(buffer);
+ var Math_imul = global.Math.imul;
+ var Math_fround = global.Math.fround;
+ var Math_abs = global.Math.abs;
+ var Math_clz32 = global.Math.clz32;
+ var Math_min = global.Math.min;
+ var Math_max = global.Math.max;
+ var Math_floor = global.Math.floor;
+ var Math_ceil = global.Math.ceil;
+ var Math_sqrt = global.Math.sqrt;
+ var abort = env.abort;
+ var nan = global.NaN;
+ var infinity = global.Infinity;
+ function $0() {
+  var i64toi32_i32$1 = 0, i64toi32_i32$0 = 0, $0_1 = Math_fround(0);
+  wasm2js_scratch_store_f64(+(305419896.0));
+  i64toi32_i32$0 = wasm2js_scratch_load_i32(1 | 0) | 0;
+  i64toi32_i32$1 = (wasm2js_scratch_store_f32($0_1), wasm2js_scratch_load_i32(2));
+  HEAP32[i64toi32_i32$1 >> 2] = wasm2js_scratch_load_i32(0 | 0) | 0;
+  HEAP32[(i64toi32_i32$1 + 4 | 0) >> 2] = i64toi32_i32$0;
+  return HEAP32[0 >> 2] | 0 | 0;
+ }
+ 
+ var FUNCTION_TABLE = [];
+ function __wasm_memory_size() {
+  return buffer.byteLength / 65536 | 0;
+ }
+ 
+ return {
+  "foo": $0
+ };
+}
+
+var memasmFunc = new ArrayBuffer(65536);
+var bufferView = new Uint8Array(memasmFunc);
+var retasmFunc = asmFunc({Math,Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,Float32Array,Float64Array,NaN,Infinity}, {abort:function() { throw new Error('abort'); }},memasmFunc);
+export var foo = retasmFunc.foo;
diff --git a/test/wasm2js/reinterpret_scratch.2asm.js.opt b/test/wasm2js/reinterpret_scratch.2asm.js.opt
new file mode 100644
index 000000000..03052fa92
--- /dev/null
+++ b/test/wasm2js/reinterpret_scratch.2asm.js.opt
@@ -0,0 +1,59 @@
+
+
+  var scratchBuffer = new ArrayBuffer(16);
+  var i32ScratchView = new Int32Array(scratchBuffer);
+  var f32ScratchView = new Float32Array(scratchBuffer);
+  var f64ScratchView = new Float64Array(scratchBuffer);
+  
+  function wasm2js_scratch_load_i32(index) {
+    return i32ScratchView[index];
+  }
+      
+  function wasm2js_scratch_store_f64(value) {
+    f64ScratchView[0] = value;
+  }
+      
+function asmFunc(global, env, buffer) {
+ var HEAP8 = new global.Int8Array(buffer);
+ var HEAP16 = new global.Int16Array(buffer);
+ var HEAP32 = new global.Int32Array(buffer);
+ var HEAPU8 = new global.Uint8Array(buffer);
+ var HEAPU16 = new global.Uint16Array(buffer);
+ var HEAPU32 = new global.Uint32Array(buffer);
+ var HEAPF32 = new global.Float32Array(buffer);
+ var HEAPF64 = new global.Float64Array(buffer);
+ var Math_imul = global.Math.imul;
+ var Math_fround = global.Math.fround;
+ var Math_abs = global.Math.abs;
+ var Math_clz32 = global.Math.clz32;
+ var Math_min = global.Math.min;
+ var Math_max = global.Math.max;
+ var Math_floor = global.Math.floor;
+ var Math_ceil = global.Math.ceil;
+ var Math_sqrt = global.Math.sqrt;
+ var abort = env.abort;
+ var nan = global.NaN;
+ var infinity = global.Infinity;
+ function $0() {
+  var $0_1 = 0;
+  wasm2js_scratch_store_f64(305419896.0);
+  $0_1 = wasm2js_scratch_load_i32(1) | 0;
+  HEAP32[0] = wasm2js_scratch_load_i32(0);
+  HEAP32[1] = $0_1;
+  return HEAP32[0];
+ }
+ 
+ var FUNCTION_TABLE = [];
+ function __wasm_memory_size() {
+  return buffer.byteLength / 65536 | 0;
+ }
+ 
+ return {
+  "foo": $0
+ };
+}
+
+var memasmFunc = new ArrayBuffer(65536);
+var bufferView = new Uint8Array(memasmFunc);
+var retasmFunc = asmFunc({Math,Int8Array,Uint8Array,Int16Array,Uint16Array,Int32Array,Uint32Array,Float32Array,Float64Array,NaN,Infinity}, {abort:function() { throw new Error('abort'); }},memasmFunc);
+export var foo = retasmFunc.foo;
diff --git a/test/wasm2js/reinterpret_scratch.wast b/test/wasm2js/reinterpret_scratch.wast
new file mode 100644
index 000000000..bfaf68380
--- /dev/null
+++ b/test/wasm2js/reinterpret_scratch.wast
@@ -0,0 +1,17 @@
+(module
+ (memory $0 1 1)
+ (func "foo" (result i32)
+  (local $0 f32)
+  (i64.store align=4
+   (i32.reinterpret_f32 ;; i32 0
+    (local.get $0)      ;; f32 0
+   )
+   (i64.reinterpret_f64    ;; these two reinterprets must not interfere with
+    (f64.const 0x12345678) ;; each other, even though both use scratch memory
+   )
+  )
+  (i32.load
+   (i32.const 0)
+  )
+ )
+)
diff --git a/test/wasm2js/unaligned.2asm.js b/test/wasm2js/unaligned.2asm.js
index 2bf7da493..7bcd22aad 100644
--- a/test/wasm2js/unaligned.2asm.js
+++ b/test/wasm2js/unaligned.2asm.js
@@ -1,7 +1,7 @@
 import { setTempRet0 } from 'env';
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -23,11 +23,11 @@ import { setTempRet0 } from 'env';
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
   function wasm2js_scratch_store_f32(value) {
-    f32ScratchView[0] = value;
+    f32ScratchView[2] = value;
   }
       
 function asmFunc(global, env, buffer) {
@@ -71,7 +71,7 @@ function asmFunc(global, env, buffer) {
  function $2() {
   var $0_1 = 0;
   $0_1 = 0;
-  return Math_fround((wasm2js_scratch_store_i32(0, HEAPU8[$0_1 >> 0] | 0 | ((HEAPU8[($0_1 + 1 | 0) >> 0] | 0) << 8 | 0) | 0 | ((HEAPU8[($0_1 + 2 | 0) >> 0] | 0) << 16 | 0 | ((HEAPU8[($0_1 + 3 | 0) >> 0] | 0) << 24 | 0) | 0) | 0), wasm2js_scratch_load_f32()));
+  return Math_fround((wasm2js_scratch_store_i32(2, HEAPU8[$0_1 >> 0] | 0 | ((HEAPU8[($0_1 + 1 | 0) >> 0] | 0) << 8 | 0) | 0 | ((HEAPU8[($0_1 + 2 | 0) >> 0] | 0) << 16 | 0 | ((HEAPU8[($0_1 + 3 | 0) >> 0] | 0) << 24 | 0) | 0) | 0), wasm2js_scratch_load_f32()));
  }
  
  function $3() {
@@ -111,7 +111,7 @@ function asmFunc(global, env, buffer) {
  function $6() {
   var $0_1 = 0, $1_1 = 0;
   $0_1 = 0;
-  $1_1 = (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(0));
+  $1_1 = (wasm2js_scratch_store_f32(Math_fround(0.0)), wasm2js_scratch_load_i32(2));
   HEAP8[$0_1 >> 0] = $1_1;
   HEAP8[($0_1 + 1 | 0) >> 0] = $1_1 >>> 8 | 0;
   HEAP8[($0_1 + 2 | 0) >> 0] = $1_1 >>> 16 | 0;
diff --git a/test/wasm2js/unaligned.2asm.js.opt b/test/wasm2js/unaligned.2asm.js.opt
index 8ab514e8f..45627f215 100644
--- a/test/wasm2js/unaligned.2asm.js.opt
+++ b/test/wasm2js/unaligned.2asm.js.opt
@@ -1,7 +1,7 @@
 import { setTempRet0 } from 'env';
 
 
-  var scratchBuffer = new ArrayBuffer(8);
+  var scratchBuffer = new ArrayBuffer(16);
   var i32ScratchView = new Int32Array(scratchBuffer);
   var f32ScratchView = new Float32Array(scratchBuffer);
   var f64ScratchView = new Float64Array(scratchBuffer);
@@ -23,7 +23,7 @@ import { setTempRet0 } from 'env';
   }
       
   function wasm2js_scratch_load_f32() {
-    return f32ScratchView[0];
+    return f32ScratchView[2];
   }
       
 function asmFunc(global, env, buffer) {
@@ -59,7 +59,7 @@ function asmFunc(global, env, buffer) {
  }
  
  function $2() {
-  return Math_fround((wasm2js_scratch_store_i32(0, HEAPU8[0] | HEAPU8[1] << 8 | (HEAPU8[2] << 16 | HEAPU8[3] << 24)), wasm2js_scratch_load_f32()));
+  return Math_fround((wasm2js_scratch_store_i32(2, HEAPU8[0] | HEAPU8[1] << 8 | (HEAPU8[2] << 16 | HEAPU8[3] << 24)), wasm2js_scratch_load_f32()));
  }
  
  function $3() {