Fix Equal and value comparison for double and float types (#3088)

(cherry picked from commit 1b5dd62)

Author: josesimoes

src/CLR/Core/CLR_RT_HeapBlock.cpp

@@ -1146,8 +1146,21 @@ CLR_UINT32 CLR_RT_HeapBlock::GetHashCode(CLR_RT_HeapBlock *ptr, bool fRecurse, C
             break;
 
         case DATATYPE_R4:
-            crc = (CLR_INT32)ptr->NumericByRef().u8.LL;
+        {
+            // ensure that NaN and both zeros have the same hash code
+            int signBit = __signbitd(ptr->NumericByRef().r4);
+
+            if (__isnanf(ptr->NumericByRef().r4) || (signBit && ptr->NumericByRef().r4 == 0))
+            {
+                crc = (CLR_INT32)(ptr->NumericByRef().u8.LL & 0x7FFFFFFF);
+            }
+            else
+            {
+                crc = (CLR_INT32)ptr->NumericByRef().u8.LL;
+            }
+
             break;
+        }
 
         case DATATYPE_U8:
             crc = ((CLR_INT32)ptr->NumericByRef().u8.LL ^ (CLR_INT32)ptr->NumericByRef().u8.HH);
@@ -1158,8 +1171,20 @@ CLR_UINT32 CLR_RT_HeapBlock::GetHashCode(CLR_RT_HeapBlock *ptr, bool fRecurse, C
             break;
 
         case DATATYPE_R8:
-            crc = ((CLR_INT32)ptr->NumericByRef().r8.LL ^ (CLR_INT32)ptr->NumericByRef().r8.HH);
+        {
+            // ensure that NaN and both zeros have the same hash code
+            int signBit = __signbitd((double)ptr->NumericByRef().r8);
+
+            if (__isnand((double)ptr->NumericByRef().r8) || (signBit && (double)ptr->NumericByRef().r8 == 0))
+            {
+                crc = (CLR_INT32)(ptr->NumericByRef().r8.LL ^ ((CLR_INT32)ptr->NumericByRef().r8.HH & 0x7FFFFFFF));
+            }
+            else
+            {
+                crc = ((CLR_INT32)ptr->NumericByRef().r8.LL ^ (CLR_INT32)ptr->NumericByRef().r8.HH);
+            }
             break;
+        }
 
         case DATATYPE_CLASS:
         case DATATYPE_VALUETYPE:

src/PAL/Include/nanoPAL_NativeDouble.h

@@ -1,4 +1,4 @@
-//
+//
 // Copyright (c) .NET Foundation and Contributors
 // Portions Copyright (c) Microsoft Corporation.  All rights reserved.
 // See LICENSE file in the project root for full license information.
@@ -14,6 +14,7 @@
 #include <float.h>
 
 #define __isnand    _isnan
+#define __isnanf    _isnan
 #define __isinfd(x) (!_finite(x))
 
 inline int __signbitd(double x)
@@ -23,7 +24,7 @@ inline int __signbitd(double x)
 }
 
 #define rint(x)         floor((x) + 0.5)
-#define remainder(x, y) ((x) - ((y)*rint((x) / (y))))
+#define remainder(x, y) ((x) - ((y) * rint((x) / (y))))
 
 #define isgreater(param0, param1) (param0 > param1)
 #define isless(param0, param1)    (param0 < param1)