diff --git a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
--- a/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
+++ b/llvm/lib/Target/WebAssembly/WebAssemblyISelLowering.cpp
@@ -644,13 +644,31 @@
   if (CLI.IsPatchPoint)
     fail(DL, DAG, "WebAssembly doesn't support patch point yet");
 
-  // Fail if tail calls are required but not enabled
-  if (!Subtarget->hasTailCall()) {
-    if ((CallConv == CallingConv::Fast && CLI.IsTailCall &&
-         MF.getTarget().Options.GuaranteedTailCallOpt) ||
-        (CLI.CS && CLI.CS.isMustTailCall()))
-      fail(DL, DAG, "WebAssembly 'tail-call' feature not enabled");
-    CLI.IsTailCall = false;
+  if (CLI.IsTailCall) {
+    bool MustTail = (CallConv == CallingConv::Fast && CLI.IsTailCall &&
+                     MF.getTarget().Options.GuaranteedTailCallOpt) ||
+                    (CLI.CS && CLI.CS.isMustTailCall());
+    if (Subtarget->hasTailCall()) {
+      // Do not tail call unless caller and callee return types match
+      const Function &F = MF.getFunction();
+      const TargetMachine &TM = getTargetMachine();
+      Type *RetTy = F.getReturnType();
+      SmallVector<MVT, 4> CallerRetTys;
+      SmallVector<MVT, 4> CalleeRetTys;
+      computeLegalValueVTs(F, TM, RetTy, CallerRetTys);
+      computeLegalValueVTs(F, TM, CLI.RetTy, CalleeRetTys);
+      bool TypesMatch = CallerRetTys.size() == CalleeRetTys.size() &&
+                        std::equal(CallerRetTys.begin(), CallerRetTys.end(),
+                                   CalleeRetTys.begin());
+      if (!TypesMatch) {
+        assert(!MustTail);
+        CLI.IsTailCall = false;
+      }
+    } else {
+      CLI.IsTailCall = false;
+      if (MustTail)
+        fail(DL, DAG, "WebAssembly 'tail-call' feature not enabled");
+    }
   }
 
   SmallVectorImpl<ISD::InputArg> &Ins = CLI.Ins;
diff --git a/llvm/test/CodeGen/WebAssembly/tailcall.ll b/llvm/test/CodeGen/WebAssembly/tailcall.ll
--- a/llvm/test/CodeGen/WebAssembly/tailcall.ll
+++ b/llvm/test/CodeGen/WebAssembly/tailcall.ll
@@ -124,6 +124,23 @@
   ret i32 %v
 }
 
+; CHECK-LABEL: mismatched_return_void:
+; CHECK: i32.call $drop=, baz, $pop{{[0-9]+}}, $pop{{[0-9]+}}, $pop{{[0-9]+}}{{$}}
+; CHECK: return{{$}}
+define void @mismatched_return_void() {
+  %v = tail call i32 @baz(i32 0, i32 42, i32 6)
+  ret void
+}
+
+; CHECK-LABEL: mismatched_return_f32:
+; CHECK: i32.call $drop=, baz, $pop{{[0-9]+}}, $pop{{[0-9]+}}, $pop{{[0-9]+}}{{$}}
+; CHECK: f32.const $push[[L:[0-9]+]]=, 0x1p0{{$}}
+; CHECK: return $pop[[L]]{{$}}
+define float @mismatched_return_f32() {
+  %v = tail call i32 @baz(i32 0, i32 42, i32 6)
+  ret float 1.
+}
+
 ; CHECK-LABEL: mismatched_byval:
 ; CHECK: i32.store
 ; CHECK: return_call quux, $pop{{[0-9]+}}{{$}}