diff --git a/lld/test/wasm/data-segments.ll b/lld/test/wasm/data-segments.ll
--- a/lld/test/wasm/data-segments.ll
+++ b/lld/test/wasm/data-segments.ll
@@ -122,7 +122,7 @@
 ; PASSIVE64-PIC-NEXT:          - Type:            I64
 ; PASSIVE-PIC-NEXT:            Count:           1
 ; PASSIVE32-PIC-NEXT:        Body:            230141B4CE006A2100200041004101FE480200044020004101427FFE0102001A05410023016A4100410DFC080000411023016A41004114FC08010020004102FE1702002000417FFE0002001A0BFC0900FC09010B
-; PASSIVE64-PIC-NEXT:        Body:            230142B4CE006A2100200041004101FE480200044020004101427FFE0102001A05420023016A4100410DFC080000421023016A41004114FC08010020004102FE1702002000417FFE0002001A0BFC0900FC09010B
+; PASSIVE64-PIC-NEXT:        Body:            230142B4CE007C2100200041004101FE480200044020004101427FFE0102001A05420023017C4100410DFC080000421023017C41004114FC08010020004102FE1702002000417FFE0002001A0BFC0900FC09010B
 ; PASSIVE-PIC-NEXT:      - Index:           3
 ; PASSIVE-PIC-NEXT:        Locals:          []
 ; PASSIVE-PIC-NEXT:        Body:            0B
diff --git a/lld/wasm/Writer.cpp b/lld/wasm/Writer.cpp
--- a/lld/wasm/Writer.cpp
+++ b/lld/wasm/Writer.cpp
@@ -1057,7 +1057,7 @@
       writeU8(os, WASM_OPCODE_GLOBAL_GET, "GLOBAL_GET");
       writeUleb128(os, WasmSym::memoryBase->getGlobalIndex(), "memory_base");
       writePtrConst(os, flagAddress, is64, "flag address");
-      writeU8(os, WASM_OPCODE_I32_ADD, "add");
+      writeU8(os, is64 ? WASM_OPCODE_I64_ADD : WASM_OPCODE_I32_ADD, "add");
       writeU8(os, WASM_OPCODE_LOCAL_SET, "local.set");
       writeUleb128(os, 0, "local 0");
     } else {
@@ -1104,7 +1104,8 @@
           writeU8(os, WASM_OPCODE_GLOBAL_GET, "GLOBAL_GET");
           writeUleb128(os, WasmSym::memoryBase->getGlobalIndex(),
                        "memory_base");
-          writeU8(os, WASM_OPCODE_I32_ADD, "i32.add");
+          writeU8(os, is64 ? WASM_OPCODE_I64_ADD : WASM_OPCODE_I32_ADD,
+                  "i32.add");
         }
         // source segment offset
         writeI32Const(os, 0, "segment offset");