Index: llvm/lib/Transforms/IPO/FunctionAttrs.cpp
===================================================================
--- llvm/lib/Transforms/IPO/FunctionAttrs.cpp
+++ llvm/lib/Transforms/IPO/FunctionAttrs.cpp
@@ -1376,10 +1376,38 @@
          !SCCNodes.contains(CB->getCalledFunction());
 }
 
+static bool canUnwindPastLandingPad(const LandingPadInst *LP) {
+  // Because phase one unwinding skips cleanup landingpads, we effectively
+  // unwind past this frame, and callers need to have valid unwind info.
+  if (LP->isCleanup())
+    return true;
+
+  for (unsigned I = 0; I < LP->getNumClauses(); ++I) {
+    Constant *Clause = LP->getClause(I);
+    // catch ptr null catches all exceptions.
+    if (LP->isCatch(I) && isa<ConstantPointerNull>(Clause))
+      return false;
+    // filter [0 x ptr] catches all exceptions.
+    if (LP->isFilter(I) && Clause->getType()->getArrayNumElements() == 0)
+      return false;
+  }
+
+  // May catch only some subset of exceptions, in which case other exceptions
+  // will continue unwinding.
+  return true;
+}
+
 /// Helper for NoUnwind inference predicate InstrBreaksAttribute.
 static bool InstrBreaksNonThrowing(Instruction &I, const SCCNodeSet &SCCNodes) {
-  if (!I.mayThrow())
+  if (!I.mayThrow()) {
+    if (auto *LP = dyn_cast<LandingPadInst>(&I))
+      return canUnwindPastLandingPad(LP);
+    // Treat cleanuppad as unwinding, for the same reasons as cleanup
+    // landingpad.
+    if (isa<CleanupPadInst>(&I))
+      return true;
     return false;
+  }
   if (const auto *CI = dyn_cast<CallInst>(&I)) {
     if (Function *Callee = CI->getCalledFunction()) {
       // I is a may-throw call to a function inside our SCC. This doesn't
Index: llvm/test/Transforms/FunctionAttrs/nounwind.ll
===================================================================
--- llvm/test/Transforms/FunctionAttrs/nounwind.ll
+++ llvm/test/Transforms/FunctionAttrs/nounwind.ll
@@ -130,7 +130,7 @@
 @catch_ty = external global ptr
 
 define void @catch_specific_landingpad() personality ptr @__gxx_personality_v0 {
-; CHECK: Function Attrs: noreturn nounwind
+; CHECK: Function Attrs: noreturn
 ; CHECK-LABEL: define {{[^@]+}}@catch_specific_landingpad
 ; CHECK-SAME: () #[[ATTR3:[0-9]+]] personality ptr @__gxx_personality_v0 {
 ; CHECK-NEXT:    invoke void @do_throw()
@@ -159,7 +159,7 @@
 define void @catch_all_landingpad() personality ptr @__gxx_personality_v0 {
 ; CHECK: Function Attrs: noreturn nounwind
 ; CHECK-LABEL: define {{[^@]+}}@catch_all_landingpad
-; CHECK-SAME: () #[[ATTR3]] personality ptr @__gxx_personality_v0 {
+; CHECK-SAME: () #[[ATTR4:[0-9]+]] personality ptr @__gxx_personality_v0 {
 ; CHECK-NEXT:    invoke void @do_throw()
 ; CHECK-NEXT:    to label [[UNREACHABLE:%.*]] unwind label [[LPAD:%.*]]
 ; CHECK:       lpad:
@@ -184,7 +184,7 @@
 }
 
 define void @filter_specific_landingpad() personality ptr @__gxx_personality_v0 {
-; CHECK: Function Attrs: noreturn nounwind
+; CHECK: Function Attrs: noreturn
 ; CHECK-LABEL: define {{[^@]+}}@filter_specific_landingpad
 ; CHECK-SAME: () #[[ATTR3]] personality ptr @__gxx_personality_v0 {
 ; CHECK-NEXT:    invoke void @do_throw()
@@ -213,7 +213,7 @@
 define void @filter_none_landingpad() personality ptr @__gxx_personality_v0 {
 ; CHECK: Function Attrs: noreturn nounwind
 ; CHECK-LABEL: define {{[^@]+}}@filter_none_landingpad
-; CHECK-SAME: () #[[ATTR3]] personality ptr @__gxx_personality_v0 {
+; CHECK-SAME: () #[[ATTR4]] personality ptr @__gxx_personality_v0 {
 ; CHECK-NEXT:    invoke void @do_throw()
 ; CHECK-NEXT:    to label [[UNREACHABLE:%.*]] unwind label [[LPAD:%.*]]
 ; CHECK:       lpad:
@@ -238,7 +238,7 @@
 }
 
 define void @cleanup_landingpad() personality ptr @__gxx_personality_v0 {
-; CHECK: Function Attrs: noreturn nounwind
+; CHECK: Function Attrs: noreturn
 ; CHECK-LABEL: define {{[^@]+}}@cleanup_landingpad
 ; CHECK-SAME: () #[[ATTR3]] personality ptr @__gxx_personality_v0 {
 ; CHECK-NEXT:    invoke void @do_throw()
@@ -265,7 +265,7 @@
 }
 
 define void @cleanuppad() personality ptr @__gxx_personality_v0 {
-; CHECK: Function Attrs: noreturn nounwind
+; CHECK: Function Attrs: noreturn
 ; CHECK-LABEL: define {{[^@]+}}@cleanuppad
 ; CHECK-SAME: () #[[ATTR3]] personality ptr @__gxx_personality_v0 {
 ; CHECK-NEXT:    invoke void @do_throw()