Fix the gtHashValue to properly hash all the bits when we have a 64-bit item

3 files changed, 40 insertions, 10 deletions

diff --git a/src/jit/compiler.hpp b/src/jit/compiler.hpp
index 9743173f5a..acc7bb688e 100644
--- a/src/jit/compiler.hpp
+++ b/src/jit/compiler.hpp
@@ -175,12 +175,25 @@ inline BOOL genMaxOneBit(unsigned value)
  *  Given a value that has exactly one bit set, return the position of that
  *  bit, in other words return the logarithm in base 2 of the given value.
  */
-
 inline unsigned genLog2(unsigned value)
 {
     return BitPosition(value);
 }
 
+// Given an unsigned 64-bit value, returns the lower 32-bits in unsigned format
+//
+inline unsigned ulo32(unsigned __int64 value)
+{
+    return static_cast<unsigned>(value);
+}
+
+// Given an unsigned 64-bit value, returns the upper 32-bits in unsigned format
+//
+inline unsigned uhi32(unsigned __int64 value)
+{
+    return static_cast<unsigned>(value >> 32);
+}
+
 /*****************************************************************************
  *
  *  Given a value that has exactly one bit set, return the position of that
@@ -189,8 +202,8 @@ inline unsigned genLog2(unsigned value)
 
 inline unsigned genLog2(unsigned __int64 value)
 {
-    unsigned lo32 = (unsigned)value;
-    unsigned hi32 = (unsigned)(value >> 32);
+    unsigned lo32 = ulo32(value);
+    unsigned hi32 = uhi32(value);
 
     if (lo32 != 0)
     {
diff --git a/src/jit/gentree.cpp b/src/jit/gentree.cpp
index c199a29772..78837c9f59 100644
--- a/src/jit/gentree.cpp
+++ b/src/jit/gentree.cpp
@@ -1885,6 +1885,7 @@ AGAIN:
 
         switch (oper)
         {
+            UINT64 bits;
             case GT_LCL_VAR:
                 add = tree->gtLclVar.gtLclNum;
                 break;
@@ -1894,16 +1895,26 @@ AGAIN:
                 break;
 
             case GT_CNS_INT:
-                add = (int)tree->gtIntCon.gtIconVal;
+                add = tree->gtIntCon.gtIconVal;
                 break;
             case GT_CNS_LNG:
-                add = (int)tree->gtLngCon.gtLconVal;
+                bits = (UINT64)tree->gtLngCon.gtLconVal;
+#ifdef _TARGET_64BIT_
+                add = bits;
+#else // 32-bit target
+                add = genTreeHashAdd(uhi32(bits), ulo32(bits));
+#endif
                 break;
             case GT_CNS_DBL:
-                add = (int)tree->gtDblCon.gtDconVal;
+                bits = *(UINT64*)(&tree->gtDblCon.gtDconVal);
+#ifdef _TARGET_64BIT_
+                add = bits;
+#else // 32-bit target
+                add = genTreeHashAdd(uhi32(bits), ulo32(bits));
+#endif
                 break;
             case GT_CNS_STR:
-                add = (int)tree->gtStrCon.gtSconCPX;
+                add = tree->gtStrCon.gtSconCPX;
                 break;
 
             case GT_JMP:
@@ -1915,8 +1926,15 @@ AGAIN:
                 break;
         }
 
-        // narrowing cast, but for hashing.
-        hash = genTreeHashAdd(hash, (unsigned)add);
+        // narrow 'add' into a 32-bit 'val'
+        unsigned val;
+#ifdef _TARGET_64BIT_
+        val = genTreeHashAdd(uhi32(add), ulo32(add));
+#else // 32-bit target
+        val = add;
+#endif
+
+        hash = genTreeHashAdd(hash, val);
         goto DONE;
     }
 
diff --git a/src/jit/gentree.h b/src/jit/gentree.h
index 6c915ce429..4c194a45a9 100644
--- a/src/jit/gentree.h
+++ b/src/jit/gentree.h
@@ -2734,7 +2734,6 @@ struct GenTreeLngCon : public GenTreeIntConCommon
     INT32 HiVal()
     {
         return (INT32)(gtLconVal >> 32);
-        ;
     }
 
     GenTreeLngCon(INT64 val) : GenTreeIntConCommon(GT_CNS_NATIVELONG, TYP_LONG)