diff --git a/llvm/lib/Target/DirectX/DXILPrepare.cpp b/llvm/lib/Target/DirectX/DXILPrepare.cpp
--- a/llvm/lib/Target/DirectX/DXILPrepare.cpp
+++ b/llvm/lib/Target/DirectX/DXILPrepare.cpp
@@ -12,8 +12,9 @@
 //===----------------------------------------------------------------------===//
 
 #include "DirectX.h"
-#include "llvm/ADT/SmallVector.h"
+#include "PointerTypeAnalysis.h"
 #include "llvm/ADT/EnumMatcher.h"
+#include "llvm/ADT/SmallVector.h"
 #include "llvm/CodeGen/Passes.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/Instruction.h"
@@ -29,28 +30,30 @@
 namespace {
 
 LLVM_ATTRIBUTE_ALWAYS_INLINE bool isValidForDXIL(Attribute::AttrKind Attr) {
-  return isInEnumSet<Attribute::AttrKind,
-      Attribute::Alignment, Attribute::AlwaysInline, Attribute::Builtin,
-      Attribute::ByVal, Attribute::InAlloca, Attribute::Cold,
-      Attribute::Convergent, Attribute::InlineHint, Attribute::InReg,
-      Attribute::JumpTable, Attribute::MinSize, Attribute::Naked,
-      Attribute::Nest, Attribute::NoAlias, Attribute::NoBuiltin,
-      Attribute::NoCapture, Attribute::NoDuplicate, Attribute::NoImplicitFloat,
-      Attribute::NoInline, Attribute::NonLazyBind, Attribute::NonNull,
-      Attribute::Dereferenceable, Attribute::DereferenceableOrNull,
-      Attribute::NoRedZone, Attribute::NoReturn, Attribute::NoUnwind,
-      Attribute::OptimizeForSize, Attribute::OptimizeNone, Attribute::ReadNone,
-      Attribute::ReadOnly, Attribute::ArgMemOnly, Attribute::Returned,
-      Attribute::ReturnsTwice, Attribute::SExt, Attribute::StackAlignment,
-      Attribute::StackProtect, Attribute::StackProtectReq,
-      Attribute::StackProtectStrong, Attribute::SafeStack, Attribute::StructRet,
-      Attribute::SanitizeAddress, Attribute::SanitizeThread,
-      Attribute::SanitizeMemory, Attribute::UWTable, Attribute::ZExt>(Attr);
+  return isInEnumSet<
+      Attribute::AttrKind, Attribute::Alignment, Attribute::AlwaysInline,
+      Attribute::Builtin, Attribute::ByVal, Attribute::InAlloca,
+      Attribute::Cold, Attribute::Convergent, Attribute::InlineHint,
+      Attribute::InReg, Attribute::JumpTable, Attribute::MinSize,
+      Attribute::Naked, Attribute::Nest, Attribute::NoAlias,
+      Attribute::NoBuiltin, Attribute::NoCapture, Attribute::NoDuplicate,
+      Attribute::NoImplicitFloat, Attribute::NoInline, Attribute::NonLazyBind,
+      Attribute::NonNull, Attribute::Dereferenceable,
+      Attribute::DereferenceableOrNull, Attribute::NoRedZone,
+      Attribute::NoReturn, Attribute::NoUnwind, Attribute::OptimizeForSize,
+      Attribute::OptimizeNone, Attribute::ReadNone, Attribute::ReadOnly,
+      Attribute::ArgMemOnly, Attribute::Returned, Attribute::ReturnsTwice,
+      Attribute::SExt, Attribute::StackAlignment, Attribute::StackProtect,
+      Attribute::StackProtectReq, Attribute::StackProtectStrong,
+      Attribute::SafeStack, Attribute::StructRet, Attribute::SanitizeAddress,
+      Attribute::SanitizeThread, Attribute::SanitizeMemory, Attribute::UWTable,
+      Attribute::ZExt>(Attr);
 }
 
 class DXILPrepareModule : public ModulePass {
 public:
   bool runOnModule(Module &M) override {
+    PointerTypeMap PointerTypes = PointerTypeAnalysis::run(M);
     for (auto &F : M.functions()) {
 #define GET_ATTR_NAMES
 #define ATTRIBUTE_ENUM(First, Second)                                          \
@@ -64,9 +67,15 @@
       for (auto &BB : F) {
         IRBuilder<> Builder(&BB);
         SmallVector<Instruction *, 4> FNegs;
+        SmallVector<LoadInst *, 4> Loads;
+        SmallVector<StoreInst *, 4> Stores;
         for (auto &I : BB) {
           if (I.getOpcode() == Instruction::FNeg)
             FNegs.push_back(&I);
+          if (I.getOpcode() == Instruction::Load)
+            Loads.push_back(cast<LoadInst>(&I));
+          if (I.getOpcode() == Instruction::Store)
+            Stores.push_back(cast<StoreInst>(&I));
         }
         for (auto I : FNegs) {
           Builder.SetInsertPoint(I);
@@ -75,6 +84,44 @@
           I->replaceAllUsesWith(Builder.CreateFSub(Zero, In));
           I->eraseFromParent();
         }
+        // Emtting NoOp bitcast instructions allows the ValueEnumerator to be
+        // unmodified as it reserves instruction IDs during contruction.
+        for (auto I : Loads) {
+          // Omit bitcasts if we only have one type
+          auto It = PointerTypes.find(I->getPointerOperand());
+          if (It != PointerTypes.end()) {
+            if (It->second->getPointerElementType() == I->getType())
+              continue;
+          }
+          // Insert bitcasts at the top of the block...
+          Builder.SetInsertPoint(I->getParent(), I->getParent()->begin());
+          Value *NoOpBitcast = Builder.Insert(
+              CastInst::Create(Instruction::BitCast, I->getPointerOperand(),
+                               I->getPointerOperandType()),
+              "");
+          Builder.SetInsertPoint(I);
+          I->replaceAllUsesWith(Builder.CreateLoad(I->getType(), NoOpBitcast));
+          I->eraseFromParent();
+        }
+        for (auto I : Stores) {
+          // Omit bitcasts if we only have one type
+          auto It = PointerTypes.find(I->getPointerOperand());
+          if (It != PointerTypes.end()) {
+            if (It->second->getPointerElementType() ==
+                I->getPointerOperandType())
+              continue;
+          }
+          // Insert bitcasts at the top of the block...
+          Builder.SetInsertPoint(I->getParent(), I->getParent()->begin());
+          Value *NoOpBitcast = Builder.Insert(
+              CastInst::Create(Instruction::BitCast, I->getPointerOperand(),
+                               I->getPointerOperandType()),
+              "");
+          Builder.SetInsertPoint(I);
+          I->replaceAllUsesWith(
+              Builder.CreateStore(I->getValueOperand(), NoOpBitcast));
+          I->eraseFromParent();
+        }
       }
     }
     return true;
diff --git a/llvm/test/CodeGen/DirectX/conflicting-bitcast-insert.ll b/llvm/test/CodeGen/DirectX/conflicting-bitcast-insert.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/conflicting-bitcast-insert.ll
@@ -0,0 +1,14 @@
+; RUN: llc --filetype=asm %s -o - | FileCheck %s
+target triple = "dxil-unknown-unknown"
+
+define i64 @test(ptr %p) {
+  store i32 0, ptr %p
+  %v = load i64, ptr %p
+  ret i64 %v
+}
+
+; CHECK: define i64 @test(ptr %p) {
+; CHECK-NEXT: %1 = bitcast ptr %p to ptr
+; CHECK-NEXT: %2 = bitcast ptr %p to ptr
+; CHECK-NEXT: store i32 0, ptr %1, align 4
+; CHECK-NEXT: %3 = load i64, ptr %2, align 8
diff --git a/llvm/test/CodeGen/DirectX/omit-bitcast-insert.ll b/llvm/test/CodeGen/DirectX/omit-bitcast-insert.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/CodeGen/DirectX/omit-bitcast-insert.ll
@@ -0,0 +1,11 @@
+; RUN: llc --filetype=asm %s -o - | FileCheck %s
+target triple = "dxil-unknown-unknown"
+
+define i64 @test(ptr %p) {
+  %v = load i64, ptr %p
+  ret i64 %v
+}
+
+; CHECK: define i64 @test(ptr %p) {
+; CHECK-NEXT: %v = load i64, ptr %p, align 8
+; CHECK-NEXT: ret i64 %v