1 files changed, 4 insertions, 3 deletions
diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
index 2e2a1194502..ac185890903 100644
--- a/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyTargetMachine.cpp
@@ -58,9 +58,9 @@ WebAssemblyTargetMachine::WebAssemblyTargetMachine(
 
   initAsmInfo();
 
-  // We need a reducible CFG, so disable some optimizations which tend to
-  // introduce irreducibility.
-  setRequiresStructuredCFG(true);
+  // Note that we don't use setRequiresStructuredCFG(true). It disables
+  // optimizations than we're ok with, and want, such as critical edge
+  // splitting and tail merging.
 }
 
 WebAssemblyTargetMachine::~WebAssemblyTargetMachine() {}
@@ -184,6 +184,7 @@ void WebAssemblyPassConfig::addPostRegAlloc() {
   disablePass(&PrologEpilogCodeInserterID);
   // Fails with: should be run after register allocation.
   disablePass(&MachineCopyPropagationID);
+  disablePass(&TailDuplicateID);
 
   if (getOptLevel() != CodeGenOpt::None) {
     // Mark registers as representing wasm's expression stack.