Fix typecast for int64_t type (#942)

* Fix typecast for int64_t type

Author: kant2002

Cesium.CodeGen/Extensions/TypeSystemEx.cs

@@ -232,6 +232,7 @@ public static bool IsSignedInteger(this IType t)
             || t.IsEqualTo(CTypeSystem.Short)
             || t.IsEqualTo(CTypeSystem.Int)
             || t.IsEqualTo(CTypeSystem.Long)
+            || t.IsEqualTo(CTypeSystem.LongLong)
             || t.IsEqualTo(CTypeSystem.NativeInt);
     }
 
@@ -275,7 +276,7 @@ public static IType GetCommonNumericType(IType a, IType b)
 
         // Otherwise, if both operands have signed integer types or both have unsigned integer types,
         // the operand with the type of lesser integer conversion rank is converted to the type of the operand with greater rank.
-        var signedTypes = new[] { CTypeSystem.SignedChar, CTypeSystem.Short, CTypeSystem.Int, CTypeSystem.Long, CTypeSystem.NativeInt};
+        var signedTypes = new[] { CTypeSystem.SignedChar, CTypeSystem.Short, CTypeSystem.Int, CTypeSystem.Long, CTypeSystem.LongLong, CTypeSystem.NativeInt};
         var unsignedTypes = new[] { CTypeSystem.Char, CTypeSystem.UnsignedChar, CTypeSystem.UnsignedShort, CTypeSystem.Unsigned, CTypeSystem.UnsignedInt, CTypeSystem.UnsignedLong, CTypeSystem.NativeUInt };
         // TODO[#381]: Move NativeInt and NativeUInt accordingly or consider them properly based on the current architecture.
 

Cesium.CodeGen/Ir/Types/CTypeSystem.cs

@@ -48,6 +48,8 @@ public static bool IsConversionAvailable(IType type, IType targetType)
             return true;
         else if (targetType.Equals(Long))
             return true;
+        else if (targetType.Equals(LongLong))
+            return true;
         else if (targetType.Equals(Char))
             return true;
         else if (targetType.Equals(UnsignedShort))
@@ -86,6 +88,8 @@ public static bool IsConversionRequired(IType type, IType targetType)
             return !type.Equals(Bool);
         else if (targetType.Equals(Long))
             return true;
+        else if (targetType.Equals(LongLong))
+            return false;
         else if (targetType.Equals(Char))
             return true;
         else if (targetType.Equals(UnsignedShort))

Cesium.IntegrationTests/type_casts.c

@@ -5,6 +5,7 @@
  */
 
 #include <stddef.h>
+#include <stdint.h>
 
 typedef struct foo_t
 {
@@ -58,5 +59,9 @@ int main(void)
 
     unsigned x = (unsigned)2;
 
+    int64_t p = 10;
+    int64_t r = o;
+    if (p != 10) return -2;
+
     return 42;
 }