Make the hashing algorithm Endian neutral. This is a bit annoying, but

folks who know something about PPC tell me that the byte swap is crazy
fast and without this the bit mixture would actually be different. It
might not be worse, but I've not measured it and so I'd rather not trust
it. This way, the algorithm is identical on both endianness hosts. I'll
look into any performance issues etc stemming from this.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@151892 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 6 insertions, 0 deletions

diff --git a/include/llvm/ADT/Hashing.h b/include/llvm/ADT/Hashing.h
index 7fbe5bb0ca..2c270e4ffc 100644
--- a/include/llvm/ADT/Hashing.h
+++ b/include/llvm/ADT/Hashing.h
@@ -47,6 +47,8 @@
 
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/DataTypes.h"
+#include "llvm/Support/Host.h"
+#include "llvm/Support/SwapByteOrder.h"
 #include "llvm/Support/type_traits.h"
 #include <algorithm>
 #include <cassert>
@@ -149,12 +151,16 @@ namespace detail {
 inline uint64_t fetch64(const char *p) {
   uint64_t result;
   memcpy(&result, p, sizeof(result));
+  if (sys::isBigEndianHost())
+    return sys::SwapByteOrder(result);
   return result;
 }
 
 inline uint32_t fetch32(const char *p) {
   uint32_t result;
   memcpy(&result, p, sizeof(result));
+  if (sys::isBigEndianHost())
+    return sys::SwapByteOrder(result);
   return result;
 }