diff --git a/llvm/lib/CodeGen/WinEHPrepare.cpp b/llvm/lib/CodeGen/WinEHPrepare.cpp
--- a/llvm/lib/CodeGen/WinEHPrepare.cpp
+++ b/llvm/lib/CodeGen/WinEHPrepare.cpp
@@ -155,11 +155,13 @@
       HT.TypeDescriptor = cast<GlobalVariable>(TypeInfo->stripPointerCasts());
     HT.Adjectives = cast<ConstantInt>(CPI->getArgOperand(1))->getZExtValue();
     HT.Handler = CPI->getParent();
-    if (auto *AI =
-            dyn_cast<AllocaInst>(CPI->getArgOperand(2)->stripPointerCasts()))
+    HT.CatchObj.Alloca = nullptr;
+    Value *V = CPI->getArgOperand(2)->stripPointerCasts();
+    auto *AI = dyn_cast<AllocaInst>(V);
+    assert((AI || isa<ConstantPointerNull>(V)) && "must be alloc or null ptr");
+    // Silently ignore dynamic allocas.
+    if (AI && AI->isStaticAlloca())
       HT.CatchObj.Alloca = AI;
-    else
-      HT.CatchObj.Alloca = nullptr;
     TBME.HandlerArray.push_back(HT);
   }
   FuncInfo.TryBlockMap.push_back(TBME);
diff --git a/llvm/test/CodeGen/X86/win-catchpad.ll b/llvm/test/CodeGen/X86/win-catchpad.ll
--- a/llvm/test/CodeGen/X86/win-catchpad.ll
+++ b/llvm/test/CodeGen/X86/win-catchpad.ll
@@ -353,3 +353,37 @@
 ; X64-NEXT: .long   -1
 ; X64-NEXT: .long   "?catch$[[catchbb]]@?0?branch_to_normal_dest@4HA"@IMGREL
 ; X64-NEXT: .long   1
+
+%struct.widget = type { i8**, i8*, [8 x i8] }
+
+@global = external global %struct.widget
+
+;; Check no crash if catch object is a dynamic alloca.
+define dso_local void @baz() local_unnamed_addr #0 personality i8* bitcast (i32 (...)* @__CxxFrameHandler3 to i8*) {
+bb:
+  br i1 poison, label %bb1, label %bb7
+
+bb1:                                              ; preds = %bb
+  %tmp = alloca i32, align 4
+  invoke void @foo()
+          to label %bb6 unwind label %bb2
+
+bb2:                                              ; preds = %bb1
+  %tmp3 = catchswitch within none [label %bb4] unwind label %bb8
+
+bb4:                                              ; preds = %bb2
+  %tmp5 = catchpad within %tmp3 [%struct.widget* @global, i32 0, i32* %tmp]
+  unreachable
+
+bb6:                                              ; preds = %bb1
+  unreachable
+
+bb7:                                              ; preds = %bb
+  ret void
+
+bb8:                                              ; preds = %bb2
+  %tmp9 = cleanuppad within none []
+  unreachable
+}
+
+declare dso_local void @foo() local_unnamed_addr