Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyCFGStackify.cpp
@@ -694,8 +694,26 @@
   }
 }
 
+// When MBB is split into MBB and Split, we should unstackify defs in MBB that
+// have their uses in Split.
+static void unstackifyVRegsUsedInSplitBB(MachineBasicBlock &MBB,
+                                         MachineBasicBlock &Split,
+                                         WebAssemblyFunctionInfo &MFI,
+                                         MachineRegisterInfo &MRI) {
+  for (auto &MI : Split) {
+    for (auto &MO : MI.explicit_uses()) {
+      if (!MO.isReg() || Register::isPhysicalRegister(MO.getReg()))
+        continue;
+      if (MachineInstr *Def = MRI.getUniqueVRegDef(MO.getReg()))
+        if (Def->getParent() == &MBB)
+          MFI.unstackifyVReg(MO.getReg());
+    }
+  }
+}
+
 bool WebAssemblyCFGStackify::fixUnwindMismatches(MachineFunction &MF) {
   const auto &TII = *MF.getSubtarget<WebAssemblySubtarget>().getInstrInfo();
+  auto &MFI = *MF.getInfo<WebAssemblyFunctionInfo>();
   MachineRegisterInfo &MRI = MF.getRegInfo();
 
   // Linearizing the control flow by placing TRY / END_TRY markers can create
@@ -1007,6 +1025,7 @@
     BrDest->insert(BrDest->end(), EndTry->removeFromParent());
     // Take out the handler body from EH pad to the new branch destination BB.
     BrDest->splice(BrDest->end(), EHPad, SplitPos, EHPad->end());
+    unstackifyVRegsUsedInSplitBB(*EHPad, *BrDest, MFI, MRI);
     // Fix predecessor-successor relationship.
     BrDest->transferSuccessors(EHPad);
     EHPad->addSuccessor(BrDest);
@@ -1122,6 +1141,7 @@
       // new nested continuation BB.
       NestedCont->splice(NestedCont->end(), MBB,
                          std::next(RangeEnd->getIterator()), MBB->end());
+      unstackifyVRegsUsedInSplitBB(*MBB, *NestedCont, MFI, MRI);
       registerTryScope(NestedTry, NestedEndTry, NestedEHPad);
 
       // Fix predecessor-successor relationship.
Index: llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
===================================================================
--- llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
+++ llvm/trunk/lib/Target/WebAssembly/WebAssemblyMachineFunctionInfo.h
@@ -101,6 +101,11 @@
       VRegStackified.resize(I + 1);
     VRegStackified.set(I);
   }
+  void unstackifyVReg(unsigned VReg) {
+    auto I = Register::virtReg2Index(VReg);
+    if (I < VRegStackified.size())
+      VRegStackified.reset(I);
+  }
   bool isVRegStackified(unsigned VReg) const {
     auto I = Register::virtReg2Index(VReg);
     if (I >= VRegStackified.size())
Index: llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
===================================================================
--- llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
+++ llvm/trunk/test/CodeGen/WebAssembly/cfg-stackify-eh.ll
@@ -436,13 +436,17 @@
 ; the right destination (label4), from which we rethrow the exception to the
 ; caller.
 
+; And the return value of 'baz' should NOT be stackified because the BB is split
+; during fixing unwind mismatches.
+
 ; NOSORT-LABEL: test6
 ; NOSORT:   try
 ; NOSORT:     call      foo
 ; --- Nested try/catch/end_try starts
 ; NOSORT:     try
 ; NOSORT:       call      bar
-; NOSORT:       call      bar
+; NOSORT:       i32.call  ${{[0-9]+}}=, baz
+; NOSORT-NOT:   i32.call  $push{{.*}}=, baz
 ; NOSORT:     catch     $[[REG:[0-9]+]]=
 ; NOSORT:       br        1                            # 1: down to label35
 ; NOSORT:     end_try
@@ -460,7 +464,8 @@
 
 bb1:                                              ; preds = %bb0
   call void @bar()
-  call void @bar()
+  %call = call i32 @baz()
+  call void @nothrow(i32 %call) #0
   ret void
 
 catch.dispatch0:                                  ; preds = %bb0
@@ -618,6 +623,9 @@
 
 declare void @foo()
 declare void @bar()
+declare i32 @baz()
+; Function Attrs: nounwind
+declare void @nothrow(i32) #0
 declare i32 @__gxx_wasm_personality_v0(...)
 declare i8* @llvm.wasm.get.exception(token)
 declare i32 @llvm.wasm.get.ehselector(token)
@@ -627,3 +635,5 @@
 declare void @__cxa_end_catch()
 declare void @__clang_call_terminate(i8*)
 declare void @_ZSt9terminatev()
+
+attributes #0 = { nounwind }