diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
index dcc393d..c33c21f 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -169,6 +169,9 @@
 
   // Mark registers as representing wasm's expression stack.
   addPass(createWebAssemblyRegStackify());
+  // The register coalescing pass has a bad interaction with COPY MIs which have
+  // EXPR_STACK as an extra operand
+  //disablePass(&RegisterCoalescerID);
 }
 
 void WebAssemblyPassConfig::addPostRegAlloc() {