diff --git a/llvm/include/llvm/Support/OnDiskHashTable.h b/llvm/include/llvm/Support/OnDiskHashTable.h
--- a/llvm/include/llvm/Support/OnDiskHashTable.h
+++ b/llvm/include/llvm/Support/OnDiskHashTable.h
@@ -17,7 +17,6 @@
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/DataTypes.h"
 #include "llvm/Support/EndianStream.h"
-#include "llvm/Support/Host.h"
 #include "llvm/Support/MathExtras.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cassert>
diff --git a/llvm/lib/Support/FoldingSet.cpp b/llvm/lib/Support/FoldingSet.cpp
--- a/llvm/lib/Support/FoldingSet.cpp
+++ b/llvm/lib/Support/FoldingSet.cpp
@@ -15,8 +15,8 @@
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Allocator.h"
 #include "llvm/Support/ErrorHandling.h"
-#include "llvm/Support/Host.h"
 #include "llvm/Support/MathExtras.h"
+#include "llvm/Support/SwapByteOrder.h"
 #include <cassert>
 #include <cstring>
 using namespace llvm;
diff --git a/llvm/lib/Support/SHA1.cpp b/llvm/lib/Support/SHA1.cpp
--- a/llvm/lib/Support/SHA1.cpp
+++ b/llvm/lib/Support/SHA1.cpp
@@ -18,15 +18,11 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Endian.h"
-#include "llvm/Support/Host.h"
+#include "llvm/Support/SwapByteOrder.h"
 #include <string.h>
 
 using namespace llvm;
 
-#if defined(BYTE_ORDER) && defined(BIG_ENDIAN) && BYTE_ORDER == BIG_ENDIAN
-#define SHA_BIG_ENDIAN
-#endif
-
 static inline uint32_t rol(uint32_t Number, int Bits) {
   return (Number << Bits) | (Number >> (32 - Bits));
 }
@@ -192,11 +188,11 @@
 }
 
 void SHA1::addUncounted(uint8_t Data) {
-#ifdef SHA_BIG_ENDIAN
-  InternalState.Buffer.C[InternalState.BufferOffset] = Data;
-#else
-  InternalState.Buffer.C[InternalState.BufferOffset ^ 3] = Data;
-#endif
+  if (sys::IsBigEndianHost) {
+    InternalState.Buffer.C[InternalState.BufferOffset] = Data;
+  } else {
+    InternalState.Buffer.C[InternalState.BufferOffset ^ 3] = Data;
+  }
 
   InternalState.BufferOffset++;
   if (InternalState.BufferOffset == BLOCK_LENGTH) {
@@ -267,20 +263,17 @@
   // Pad to complete the last block
   pad();
 
-#ifdef SHA_BIG_ENDIAN
-  // Just copy the current state
-  for (int i = 0; i < 5; i++) {
-    HashResult[i] = InternalState.State[i];
-  }
-#else
-  // Swap byte order back
-  for (int i = 0; i < 5; i++) {
-    HashResult[i] = (((InternalState.State[i]) << 24) & 0xff000000) |
-                    (((InternalState.State[i]) << 8) & 0x00ff0000) |
-                    (((InternalState.State[i]) >> 8) & 0x0000ff00) |
-                    (((InternalState.State[i]) >> 24) & 0x000000ff);
+  if (sys::IsBigEndianHost) {
+    // Just copy the current state
+    for (int i = 0; i < 5; i++) {
+      HashResult[i] = InternalState.State[i];
+    }
+  } else {
+    // Swap byte order back
+    for (int i = 0; i < 5; i++) {
+      HashResult[i] = sys::getSwappedBytes(InternalState.State[i]);
+    }
   }
-#endif
 }
 
 std::array<uint8_t, 20> SHA1::final() {
diff --git a/llvm/lib/Support/SHA256.cpp b/llvm/lib/Support/SHA256.cpp
--- a/llvm/lib/Support/SHA256.cpp
+++ b/llvm/lib/Support/SHA256.cpp
@@ -23,15 +23,11 @@
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/StringRef.h"
 #include "llvm/Support/Endian.h"
-#include "llvm/Support/Host.h"
+#include "llvm/Support/SwapByteOrder.h"
 #include <string.h>
 
 namespace llvm {
 
-#if defined(BYTE_ORDER) && defined(BIG_ENDIAN) && BYTE_ORDER == BIG_ENDIAN
-#define SHA_BIG_ENDIAN
-#endif
-
 #define SHR(x, c) ((x) >> (c))
 #define ROTR(x, n) (((x) >> n) | ((x) << (32 - (n))))
 
@@ -171,11 +167,11 @@
 }
 
 void SHA256::addUncounted(uint8_t Data) {
-#ifdef SHA_BIG_ENDIAN
-  InternalState.Buffer.C[InternalState.BufferOffset] = Data;
-#else
-  InternalState.Buffer.C[InternalState.BufferOffset ^ 3] = Data;
-#endif
+  if (sys::IsBigEndianHost) {
+    InternalState.Buffer.C[InternalState.BufferOffset] = Data;
+  } else {
+    InternalState.Buffer.C[InternalState.BufferOffset ^ 3] = Data;
+  }
 
   InternalState.BufferOffset++;
   if (InternalState.BufferOffset == BLOCK_LENGTH) {
@@ -247,20 +243,17 @@
   // Pad to complete the last block
   pad();
 
-#ifdef SHA_BIG_ENDIAN
-  // Just copy the current state
-  for (int i = 0; i < 8; i++) {
-    HashResult[i] = InternalState.State[i];
-  }
-#else
-  // Swap byte order back
-  for (int i = 0; i < 8; i++) {
-    HashResult[i] = (((InternalState.State[i]) << 24) & 0xff000000) |
-                    (((InternalState.State[i]) << 8) & 0x00ff0000) |
-                    (((InternalState.State[i]) >> 8) & 0x0000ff00) |
-                    (((InternalState.State[i]) >> 24) & 0x000000ff);
+  if (sys::IsBigEndianHost) {
+    // Just copy the current state
+    for (int i = 0; i < 8; i++) {
+      HashResult[i] = InternalState.State[i];
+    }
+  } else {
+    // Swap byte order back
+    for (int i = 0; i < 8; i++) {
+      HashResult[i] = sys::getSwappedBytes(InternalState.State[i]);
+    }
   }
-#endif
 }
 
 std::array<uint8_t, 32> SHA256::final() {