Index: llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp
===================================================================
--- llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp
+++ llvm/trunk/lib/Analysis/MemorySSAUpdater.cpp
@@ -339,6 +339,9 @@
       ForwardIDFCalculator IDFs(*MSSA->DT);
       SmallVector<BasicBlock *, 32> IDFBlocks;
       SmallPtrSet<BasicBlock *, 2> DefiningBlocks;
+      for (const auto &VH : InsertedPHIs)
+        if (const auto *RealPHI = cast_or_null<MemoryPhi>(VH))
+          DefiningBlocks.insert(RealPHI->getBlock());
       DefiningBlocks.insert(MD->getBlock());
       IDFs.setDefiningBlocks(DefiningBlocks);
       IDFs.calculate(IDFBlocks);
Index: llvm/trunk/test/Analysis/MemorySSA/pr43320.ll
===================================================================
--- llvm/trunk/test/Analysis/MemorySSA/pr43320.ll
+++ llvm/trunk/test/Analysis/MemorySSA/pr43320.ll
@@ -0,0 +1,33 @@
+; RUN: opt -licm -enable-mssa-loop-dependency -verify-memoryssa -S < %s | FileCheck %s
+; REQUIRES: asserts
+
+target datalayout = "e-m:e-i8:8:32-i16:16:32-i64:64-i128:128-n32:64-S128"
+target triple = "aarch64-unknown-none-eabi"
+
+; CHECK-LABEL: @e()
+define void @e() {
+entry:
+  br label %g
+
+g:                                                ; preds = %cleanup, %entry
+  %0 = load i32, i32* null, align 4
+  %and = and i32 %0, undef
+  store i32 %and, i32* null, align 4
+  br i1 undef, label %if.end8, label %if.then
+
+if.then:                                          ; preds = %g
+  br i1 undef, label %k, label %cleanup
+
+k:                                                ; preds = %if.end8, %if.then
+  br i1 undef, label %if.end8, label %cleanup
+
+if.end8:                                          ; preds = %k, %g
+  br i1 undef, label %for.cond.preheader, label %k
+
+for.cond.preheader:                               ; preds = %if.end8
+  unreachable
+
+cleanup:                                          ; preds = %k, %if.then
+  br label %g
+}
+