diff --git a/llvm/include/llvm/IR/Value.h b/llvm/include/llvm/IR/Value.h
--- a/llvm/include/llvm/IR/Value.h
+++ b/llvm/include/llvm/IR/Value.h
@@ -484,7 +484,7 @@
   void dropDroppableUsesIn(User &Usr);
 
   /// Remove the droppable use \p U.
-  void dropDroppableUse(Use &U);
+  static void dropDroppableUse(Use &U);
 
   /// Check if this value is used in the specified basic block.
   bool isUsedInBasicBlock(const BasicBlock *BB) const;
diff --git a/llvm/lib/IR/Value.cpp b/llvm/lib/IR/Value.cpp
--- a/llvm/lib/IR/Value.cpp
+++ b/llvm/lib/IR/Value.cpp
@@ -205,7 +205,7 @@
     else {
       U.set(UndefValue::get(U.get()->getType()));
       CallInst::BundleOpInfo &BOI = Assume->getBundleOpInfoForOperand(OpNo);
-      BOI.Tag = getContext().pImpl->getOrInsertBundleTag("ignore");
+      BOI.Tag = Assume->getContext().pImpl->getOrInsertBundleTag("ignore");
     }
     return;
   }
diff --git a/llvm/lib/Transforms/Scalar/SROA.cpp b/llvm/lib/Transforms/Scalar/SROA.cpp
--- a/llvm/lib/Transforms/Scalar/SROA.cpp
+++ b/llvm/lib/Transforms/Scalar/SROA.cpp
@@ -268,6 +268,11 @@
   /// Access the dead users for this alloca.
   ArrayRef<Instruction *> getDeadUsers() const { return DeadUsers; }
 
+  /// Access Uses that should be dropped if the alloca is promotable.
+  ArrayRef<Use *> getDeadUsesIfPromotable() const {
+    return DeadUseIfPromotable;
+  }
+
   /// Access the dead operands referring to this alloca.
   ///
   /// These are operands which have cannot actually be used to refer to the
@@ -322,6 +327,9 @@
   /// they come from outside of the allocated space.
   SmallVector<Instruction *, 8> DeadUsers;
 
+  /// Uses which will become dead if can promote the alloca.
+  SmallVector<Use *, 8> DeadUseIfPromotable;
+
   /// Operands which will become dead if we rewrite the alloca.
   ///
   /// These are operands that in their particular use can be replaced with
@@ -926,8 +934,10 @@
   // FIXME: What about debug intrinsics? This matches old behavior, but
   // doesn't make sense.
   void visitIntrinsicInst(IntrinsicInst &II) {
-    if (II.isDroppable())
+    if (II.isDroppable()) {
+      AS.DeadUseIfPromotable.push_back(U);
       return;
+    }
 
     if (!IsOffsetKnown)
       return PI.setAborted(&II);
@@ -4350,6 +4360,13 @@
     }
 
   if (Promotable) {
+    for (Use *U : AS.getDeadUsesIfPromotable()) {
+      auto *OldInst = dyn_cast<Instruction>(U->get());
+      Value::dropDroppableUse(*U);
+      if (OldInst)
+        if (isInstructionTriviallyDead(OldInst))
+          DeadInsts.insert(OldInst);
+    }
     if (PHIUsers.empty() && SelectUsers.empty()) {
       // Promote the alloca.
       PromotableAllocas.push_back(NewAI);
diff --git a/llvm/test/Transforms/SROA/assume.ll b/llvm/test/Transforms/SROA/assume.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/Transforms/SROA/assume.ll
@@ -0,0 +1,32 @@
+; NOTE: Assertions have been autogenerated by utils/update_test_checks.py
+; RUN: opt < %s -sroa -S | FileCheck %s
+
+source_filename = "tmp.cpp"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+%struct.n.2 = type { i8 }
+%struct.bi = type { %class.as }
+%class.as = type { %class.ao }
+%class.ao = type { %class.ai }
+%class.ai = type { i32, i32 }
+
+define linkonce_odr dso_local void @_ZN2bg2baIiEC2ES_() unnamed_addr align 2 {
+; CHECK-LABEL: @_ZN2bg2baIiEC2ES_(
+; CHECK-NEXT:  entry:
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "ignore"(%struct.bi* undef) ]
+; CHECK-NEXT:    ret void
+;
+entry:
+  %y = alloca i64, align 8
+  store i64 undef, i64* %y, align 8
+  %0 = bitcast i64* %y to %struct.n.2*
+  %1 = bitcast %struct.n.2* %0 to %struct.bi*
+  call void @llvm.assume(i1 true) [ "nonnull"(%struct.bi* %1) ]
+  ret void
+}
+
+; Function Attrs: nofree norecurse nounwind willreturn
+declare void @llvm.assume(i1) #0
+
+attributes #0 = { nofree norecurse nounwind willreturn }
diff --git a/llvm/test/Transforms/SROA/ignore-droppable.ll b/llvm/test/Transforms/SROA/ignore-droppable.ll
--- a/llvm/test/Transforms/SROA/ignore-droppable.ll
+++ b/llvm/test/Transforms/SROA/ignore-droppable.ll
@@ -38,9 +38,8 @@
 
 define void @positive_multiple_assume_uses() {
 ; CHECK-LABEL: @positive_multiple_assume_uses(
-; CHECK-NEXT:    [[A:%.*]] = alloca { i8, i16 }, align 8
-; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"({ i8, i16 }* [[A]], i64 8), "align"({ i8, i16 }* [[A]], i64 16) ]
-; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "nonnull"({ i8, i16 }* [[A]]), "align"({ i8, i16 }* [[A]], i64 2) ]
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "ignore"({ i8, i16 }* undef, i64 8), "ignore"({ i8, i16 }* undef, i64 16) ]
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "ignore"({ i8, i16 }* undef), "ignore"({ i8, i16 }* undef, i64 2) ]
 ; CHECK-NEXT:    ret void
 ;
   %A = alloca {i8, i16}
@@ -52,10 +51,8 @@
 
 define void @positive_gep_assume_uses() {
 ; CHECK-LABEL: @positive_gep_assume_uses(
-; CHECK-NEXT:    [[A:%.*]] = alloca { i8, i16 }, align 8
-; CHECK-NEXT:    [[B:%.*]] = getelementptr { i8, i16 }, { i8, i16 }* [[A]], i32 0, i32 0
-; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "align"(i8* [[B]], i64 8), "align"(i8* [[B]], i64 16) ]
-; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "nonnull"(i8* [[B]]), "align"(i8* [[B]], i64 2) ]
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "ignore"(i8* undef, i64 8), "ignore"(i8* undef, i64 16) ]
+; CHECK-NEXT:    call void @llvm.assume(i1 true) [ "ignore"(i8* undef), "ignore"(i8* undef, i64 2) ]
 ; CHECK-NEXT:    ret void
 ;
   %A = alloca {i8, i16}