diff --git a/src/growableHeap.js b/src/growableHeap.js
index 6169ab5909ef6..099df836d0768 100644
--- a/src/growableHeap.js
+++ b/src/growableHeap.js
@@ -42,6 +42,18 @@ function GROWABLE_HEAP_U32() {
   }
   return HEAPU32;
 }
+function GROWABLE_HEAP_I64() {
+  if (wasmMemory.buffer != HEAP8.buffer) {
+    updateMemoryViews();
+  }
+  return HEAP64;
+}
+function GROWABLE_HEAP_U64() {
+  if (wasmMemory.buffer != HEAP8.buffer) {
+    updateMemoryViews();
+  }
+  return HEAPU64;
+}
 function GROWABLE_HEAP_F32() {
   if (wasmMemory.buffer != HEAP8.buffer) {
     updateMemoryViews();
diff --git a/src/lib/liblittle_endian_heap.js b/src/lib/liblittle_endian_heap.js
index 571cea68f462d..1f97eb6530010 100644
--- a/src/lib/liblittle_endian_heap.js
+++ b/src/lib/liblittle_endian_heap.js
@@ -11,6 +11,12 @@ var LibraryLittleEndianHeap = {
   $LE_HEAP_STORE_I32: (byteOffset, value) =>
     HEAP_DATA_VIEW.setInt32(byteOffset, value, true),
 
+  $LE_HEAP_STORE_U64: (byteOffset, value) =>
+    HEAP_DATA_VIEW.setBigUint64(byteOffset, value, true),
+
+  $LE_HEAP_STORE_I64: (byteOffset, value) =>
+    HEAP_DATA_VIEW.setBigInt64(byteOffset, value, true),
+
   $LE_HEAP_STORE_F32: (byteOffset, value) =>
     HEAP_DATA_VIEW.setFloat32(byteOffset, value, true),
 
@@ -29,6 +35,12 @@ var LibraryLittleEndianHeap = {
   $LE_HEAP_LOAD_I32: (byteOffset) =>
     HEAP_DATA_VIEW.getInt32(byteOffset, true),
 
+  $LE_HEAP_LOAD_U64: (byteOffset) =>
+    HEAP_DATA_VIEW.getBigUint64(byteOffset, true),
+
+  $LE_HEAP_LOAD_I64: (byteOffset) =>
+    HEAP_DATA_VIEW.getBigInt64(byteOffset, true),
+
   $LE_HEAP_LOAD_F32: (byteOffset) =>
     HEAP_DATA_VIEW.getFloat32(byteOffset, true),
 
diff --git a/src/modules.mjs b/src/modules.mjs
index b03cdfe9008d9..cd5ef5fc51694 100644
--- a/src/modules.mjs
+++ b/src/modules.mjs
@@ -462,6 +462,8 @@ function exportRuntimeSymbols() {
       'GROWABLE_HEAP_U16',
       'GROWABLE_HEAP_I32',
       'GROWABLE_HEAP_U32',
+      'GROWABLE_HEAP_I64',
+      'GROWABLE_HEAP_U64',
       'GROWABLE_HEAP_F32',
       'GROWABLE_HEAP_F64',
     );
diff --git a/src/runtime_asan.js b/src/runtime_asan.js
index babc684d04ffc..dd32df2aab2b7 100644
--- a/src/runtime_asan.js
+++ b/src/runtime_asan.js
@@ -43,6 +43,16 @@ function _asan_js_load_4u(ptr) {
   return HEAPU32[ptr];
 }
 /** @suppress{duplicate} */
+function _asan_js_load_8(ptr) {
+  if (runtimeInitialized) return __asan_c_load_8(ptr);
+  return HEAP64[ptr];
+}
+/** @suppress{duplicate} */
+function _asan_js_load_8u(ptr) {
+  if (runtimeInitialized) return BigInt.asUintN(64, __asan_c_load_8u(ptr));
+  return HEAPU64[ptr];
+}
+/** @suppress{duplicate} */
 function _asan_js_load_f(ptr) {
   if (runtimeInitialized) return __asan_c_load_f(ptr);
   return HEAPF32[ptr];
@@ -84,6 +94,19 @@ function _asan_js_store_4u(ptr, val) {
   return HEAPU32[ptr] = val;
 }
 /** @suppress{duplicate} */
+function _asan_js_store_8(ptr, val) {
+  if (runtimeInitialized) return __asan_c_store_8(ptr, val);
+  return HEAP64[ptr] = val;
+}
+/** @suppress{duplicate} */
+function _asan_js_store_8u(ptr, val) {
+  if (runtimeInitialized) {
+    __asan_c_store_8u(ptr, val);
+    return val;
+  }
+  return HEAPU64[ptr] = val;
+}
+/** @suppress{duplicate} */
 function _asan_js_store_f(ptr, val) {
   if (runtimeInitialized) return __asan_c_store_f(ptr, val);
   return HEAPF32[ptr] = val;
diff --git a/system/lib/asan_js.c b/system/lib/asan_js.c
index 58e4e97dc24cd..a349270479ea6 100644
--- a/system/lib/asan_js.c
+++ b/system/lib/asan_js.c
@@ -45,6 +45,14 @@ uint32_t _asan_c_load_4u(uintptr_t shifted) {
   uint32_t* ptr = (uint32_t*)(shifted << 2);
   return *ptr;
 }
+int64_t _asan_c_load_8(uintptr_t shifted) {
+  int64_t* ptr = (int64_t*)(shifted << 3);
+  return *ptr;
+}
+uint64_t _asan_c_load_8u(uintptr_t shifted) {
+  uint64_t* ptr = (uint64_t*)(shifted << 3);
+  return *ptr;
+}
 float _asan_c_load_f(uintptr_t shifted) {
   float* ptr = (float*)(shifted << 2);
   return *ptr;
@@ -79,6 +87,14 @@ uint32_t _asan_c_store_4u(uintptr_t shifted, uint32_t val) {
   uint32_t* ptr = (uint32_t*)(shifted << 2);
   return *ptr = val;
 }
+int64_t _asan_c_store_8(uintptr_t shifted, int64_t val) {
+  int64_t* ptr = (int64_t*)(shifted << 3);
+  return *ptr = val;
+}
+uint64_t _asan_c_store_8u(uintptr_t shifted, uint64_t val) {
+  uint64_t* ptr = (uint64_t*)(shifted << 3);
+  return *ptr = val;
+}
 float _asan_c_store_f(uintptr_t shifted, float val) {
   float* ptr = (float*)(shifted << 2);
   return *ptr = val;
diff --git a/test/js_optimizer/asanify-output.js b/test/js_optimizer/asanify-output.js
index 099b88c616f25..6308bf7e8afc8 100644
--- a/test/js_optimizer/asanify-output.js
+++ b/test/js_optimizer/asanify-output.js
@@ -14,6 +14,10 @@ _asan_js_store_f(x, 7);
 
 _asan_js_store_d(x, 8);
 
+_asan_js_store_8(x, 9n);
+
+_asan_js_store_8u(x, 10n);
+
 a1 = _asan_js_load_1(x);
 
 a2 = _asan_js_load_2(x);
@@ -30,6 +34,10 @@ a7 = _asan_js_load_f(x);
 
 a8 = _asan_js_load_d(x);
 
+a9 = _asan_js_load_8(x);
+
+a10 = _asan_js_load_8u(x);
+
 foo = _asan_js_store_1u(1337, 42);
 
 _asan_js_load_2(bar(_asan_js_load_d(5)));
diff --git a/test/js_optimizer/asanify.js b/test/js_optimizer/asanify.js
index 6d8ff13cddb89..bba03a1d5da90 100644
--- a/test/js_optimizer/asanify.js
+++ b/test/js_optimizer/asanify.js
@@ -7,6 +7,8 @@ HEAPU16[x] = 5;
 HEAPU32[x] = 6;
 HEAPF32[x] = 7;
 HEAPF64[x] = 8;
+HEAP64[x] = 9n;
+HEAPU64[x] = 10n;
 
 // loads
 a1 = HEAP8[x];
@@ -17,6 +19,8 @@ a5 = HEAPU16[x];
 a6 = HEAPU32[x];
 a7 = HEAPF32[x];
 a8 = HEAPF64[x];
+a9 = HEAP64[x];
+a10 = HEAPU64[x];
 
 // store return value
 foo = HEAPU8[1337] = 42;
diff --git a/test/js_optimizer/growableHeap-output.js b/test/js_optimizer/growableHeap-output.js
index 8ad2f21f2afec..0e70a486b170c 100644
--- a/test/js_optimizer/growableHeap-output.js
+++ b/test/js_optimizer/growableHeap-output.js
@@ -3,6 +3,7 @@ function f() {
   GROWABLE_HEAP_I32()[$0 >> 2] = $2 + 1;
   $9 = GROWABLE_HEAP_U8()[$2 >> 0] | 0;
   +GROWABLE_HEAP_F64()[x >> 3];
+  GROWABLE_HEAP_I64()[x >> 3] = GROWABLE_HEAP_I64()[y >> 3];
 }
 
 function libraryFunc(ptr, val) {
diff --git a/test/js_optimizer/growableHeap.js b/test/js_optimizer/growableHeap.js
index e7b92ec8e8a9e..c14766733c7bd 100644
--- a/test/js_optimizer/growableHeap.js
+++ b/test/js_optimizer/growableHeap.js
@@ -3,6 +3,7 @@ function f() {
     HEAP32[$0 >> 2] = $2 + 1;
     $9 = HEAPU8[$2 >> 0] | 0;
     +HEAPF64[x >> 3];
+    HEAP64[x >> 3] = HEAP64[y >> 3];
 }
 
 function libraryFunc(ptr, val) {
diff --git a/test/js_optimizer/safeHeap-output.js b/test/js_optimizer/safeHeap-output.js
index e6e06c7740e50..cc7bfddca7e77 100644
--- a/test/js_optimizer/safeHeap-output.js
+++ b/test/js_optimizer/safeHeap-output.js
@@ -14,6 +14,10 @@ SAFE_HEAP_STORE_D(x * 4, 7, 4);
 
 SAFE_HEAP_STORE_D(x * 8, 8, 8);
 
+SAFE_HEAP_STORE(x * 8, 9n, 8);
+
+SAFE_HEAP_STORE(x * 8, 10n, 8);
+
 a1 = SAFE_HEAP_LOAD(x, 1, 0);
 
 a2 = SAFE_HEAP_LOAD(x * 2, 2, 0);
@@ -30,6 +34,10 @@ a7 = SAFE_HEAP_LOAD_D(x * 4, 4, 0);
 
 a8 = SAFE_HEAP_LOAD_D(x * 8, 8, 0);
 
+a9 = SAFE_HEAP_LOAD(x * 8, 8, 0);
+
+a10 = SAFE_HEAP_LOAD(x * 8, 8, 1);
+
 foo = SAFE_HEAP_STORE(1337, 42, 1);
 
 SAFE_HEAP_LOAD(bar(SAFE_HEAP_LOAD_D(5 * 8, 8, 0)) * 2, 2, 0);
diff --git a/test/js_optimizer/safeHeap.js b/test/js_optimizer/safeHeap.js
index 8f5e567101257..0f6a88b108b06 100644
--- a/test/js_optimizer/safeHeap.js
+++ b/test/js_optimizer/safeHeap.js
@@ -7,6 +7,8 @@ HEAPU16[x] = 5;
 HEAPU32[x] = 6;
 HEAPF32[x] = 7;
 HEAPF64[x] = 8;
+HEAP64[x] = 9n;
+HEAPU64[x] = 10n;
 
 // loads
 a1 = HEAP8[x];
@@ -17,6 +19,8 @@ a5 = HEAPU16[x];
 a6 = HEAPU32[x];
 a7 = HEAPF32[x];
 a8 = HEAPF64[x];
+a9 = HEAP64[x];
+a10 = HEAPU64[x];
 
 // store return value
 foo = HEAPU8[1337] = 42;
diff --git a/test/js_optimizer/unsignPointers-output.js b/test/js_optimizer/unsignPointers-output.js
index 69f9beaa63506..3a87c8980708c 100644
--- a/test/js_optimizer/unsignPointers-output.js
+++ b/test/js_optimizer/unsignPointers-output.js
@@ -27,13 +27,16 @@ HEAPU8.subarray(x >>> 0);
 
 HEAPU8.subarray(x >>> 0, y >>> 0);
 
+// something completely different
 process.versions.node;
 
-// something completely different
 insideCall(HEAP32[x >>> 2]);
 
 heap[x >>> 0];
 
 HEAP[x >>> 0];
 
+// but not this
 HeAp[x];
+
+HEAP64[x >>> 3] = HEAPU64[y >>> 0];
diff --git a/test/js_optimizer/unsignPointers.js b/test/js_optimizer/unsignPointers.js
index 93159f496571e..7494d3c94d59c 100644
--- a/test/js_optimizer/unsignPointers.js
+++ b/test/js_optimizer/unsignPointers.js
@@ -30,7 +30,8 @@ HEAPU8.subarray(x);
 
 HEAPU8.subarray(x, y);
 
-process.versions.node; // something completely different
+// something completely different
+process.versions.node;
 
 insideCall(HEAP32[x >> 2]);
 
@@ -38,4 +39,7 @@ heap[x];
 
 HEAP[x];
 
-HeAp[x]; // but not this
+// but not this
+HeAp[x];
+
+HEAP64[x >> 3] = HEAPU64[y];
diff --git a/tools/acorn-optimizer.mjs b/tools/acorn-optimizer.mjs
index 50e5cb9de3d17..379412e20349f 100755
--- a/tools/acorn-optimizer.mjs
+++ b/tools/acorn-optimizer.mjs
@@ -1114,6 +1114,8 @@ function isEmscriptenHEAP(name) {
     case 'HEAPU16':
     case 'HEAP32':
     case 'HEAPU32':
+    case 'HEAP64':
+    case 'HEAPU64':
     case 'HEAPF32':
     case 'HEAPF64': {
       return true;
@@ -1182,6 +1184,16 @@ function littleEndianHeap(ast) {
             makeCallExpression(node, 'LE_HEAP_STORE_U32', [multiply(idx, 4), value]);
             break;
           }
+          case 'HEAP64': {
+            // change "name[idx] = value" to "LE_HEAP_STORE_I64(idx*8, value)"
+            makeCallExpression(node, 'LE_HEAP_STORE_I64', [multiply(idx, 8), value]);
+            break;
+          }
+          case 'HEAPU64': {
+            // change "name[idx] = value" to "LE_HEAP_STORE_U64(idx*8, value)"
+            makeCallExpression(node, 'LE_HEAP_STORE_U64', [multiply(idx, 8), value]);
+            break;
+          }
           case 'HEAPF32': {
             // change "name[idx] = value" to "LE_HEAP_STORE_F32(idx*4, value)"
             makeCallExpression(node, 'LE_HEAP_STORE_F32', [multiply(idx, 4), value]);
@@ -1250,6 +1262,16 @@ function littleEndianHeap(ast) {
             makeCallExpression(node, 'LE_HEAP_LOAD_U32', [multiply(idx, 4)]);
             break;
           }
+          case 'HEAP64': {
+            // change "name[idx]" to "LE_HEAP_LOAD_I64(idx*8)"
+            makeCallExpression(node, 'LE_HEAP_LOAD_I64', [multiply(idx, 8)]);
+            break;
+          }
+          case 'HEAPU64': {
+            // change "name[idx]" to "LE_HEAP_LOAD_U64(idx*8)"
+            makeCallExpression(node, 'LE_HEAP_LOAD_U64', [multiply(idx, 8)]);
+            break;
+          }
           case 'HEAPF32': {
             // change "name[idx]" to "LE_HEAP_LOAD_F32(idx*4)"
             makeCallExpression(node, 'LE_HEAP_LOAD_F32', [multiply(idx, 4)]);
@@ -1328,6 +1350,14 @@ function growableHeap(ast) {
             makeCallExpression(node, 'GROWABLE_HEAP_U32', []);
             break;
           }
+          case 'HEAP64': {
+            makeCallExpression(node, 'GROWABLE_HEAP_I64', []);
+            break;
+          }
+          case 'HEAPU64': {
+            makeCallExpression(node, 'GROWABLE_HEAP_U64', []);
+            break;
+          }
           case 'HEAPF32': {
             makeCallExpression(node, 'GROWABLE_HEAP_F32', []);
             break;
@@ -1470,6 +1500,14 @@ function asanify(ast) {
             makeCallExpression(node, '_asan_js_store_4u', [ptr, value]);
             break;
           }
+          case 'HEAP64': {
+            makeCallExpression(node, '_asan_js_store_8', [ptr, value]);
+            break;
+          }
+          case 'HEAPU64': {
+            makeCallExpression(node, '_asan_js_store_8u', [ptr, value]);
+            break;
+          }
           case 'HEAPF32': {
             makeCallExpression(node, '_asan_js_store_f', [ptr, value]);
             break;
@@ -1515,6 +1553,14 @@ function asanify(ast) {
             makeCallExpression(node, '_asan_js_load_4u', [ptr]);
             break;
           }
+          case 'HEAP64': {
+            makeCallExpression(node, '_asan_js_load_8', [ptr]);
+            break;
+          }
+          case 'HEAPU64': {
+            makeCallExpression(node, '_asan_js_load_8u', [ptr]);
+            break;
+          }
           case 'HEAPF32': {
             makeCallExpression(node, '_asan_js_load_f', [ptr]);
             break;
@@ -1585,6 +1631,15 @@ function safeHeap(ast) {
             ]);
             break;
           }
+          case 'HEAP64':
+          case 'HEAPU64': {
+            makeCallExpression(node, 'SAFE_HEAP_STORE', [
+              multiply(ptr, 8),
+              value,
+              createLiteral(8),
+            ]);
+            break;
+          }
           case 'HEAPF32': {
             makeCallExpression(node, 'SAFE_HEAP_STORE_D', [
               multiply(ptr, 4),
@@ -1654,6 +1709,22 @@ function safeHeap(ast) {
             ]);
             break;
           }
+          case 'HEAP64': {
+            makeCallExpression(node, 'SAFE_HEAP_LOAD', [
+              multiply(ptr, 8),
+              createLiteral(8),
+              createLiteral(0),
+            ]);
+            break;
+          }
+          case 'HEAPU64': {
+            makeCallExpression(node, 'SAFE_HEAP_LOAD', [
+              multiply(ptr, 8),
+              createLiteral(8),
+              createLiteral(1),
+            ]);
+            break;
+          }
           case 'HEAPF32': {
             makeCallExpression(node, 'SAFE_HEAP_LOAD_D', [
               multiply(ptr, 4),
diff --git a/tools/emscripten.py b/tools/emscripten.py
index b3c2801f2370a..b1660fd6b0e75 100644
--- a/tools/emscripten.py
+++ b/tools/emscripten.py
@@ -44,10 +44,12 @@
   '_asan_c_load_1', '_asan_c_load_1u',
   '_asan_c_load_2', '_asan_c_load_2u',
   '_asan_c_load_4', '_asan_c_load_4u',
+  '_asan_c_load_8', '_asan_c_load_8u',
   '_asan_c_load_f', '_asan_c_load_d',
   '_asan_c_store_1', '_asan_c_store_1u',
   '_asan_c_store_2', '_asan_c_store_2u',
   '_asan_c_store_4', '_asan_c_store_4u',
+  '_asan_c_store_8', '_asan_c_store_8u',
   '_asan_c_store_f', '_asan_c_store_d',
 ]