[FRONTEND] Differentiate between bool and int in the frontend (#1678)

`bool` is a subclass of `int`, so `isinstance(bool_var, int) == True`,
and a `bool` constant will be converted to an `int` constant.

In triton specifically, if a bool var is treated as an integer, it
prevents us using the `logical_and` operator which requires both
operands have the same bit length.

> Cannot bitcast data-type of size 32 to data-type of size 1

By differentiating int and bool, it allows us to make the syntax more
close to native python. We can now use `if bool_var and condition` to
check the truthiness, and `if bool_var is True` to check identity.

python/test/unit/language/test_core.py

@@ -2381,26 +2381,32 @@ def test_call(type):
 # -------------
 
 
-@pytest.mark.parametrize("if_type", ["if", "if_exp"])
+@pytest.mark.parametrize("if_type", ["if", "if_exp", "if_and"])
 def test_if(if_type):
 
     @triton.jit
-    def kernel(Cond, XTrue, XFalse, Ret, IfType: tl.constexpr):
+    def kernel(Cond, XTrue, XFalse, Ret, IfType: tl.constexpr, BoolVar: tl.constexpr):
         pid = tl.program_id(0)
         cond = tl.load(Cond)
         if IfType == "if":
-            if pid % 2:
+            if pid % 2 == 0:
                 tl.store(Ret, tl.load(XTrue))
             else:
                 tl.store(Ret, tl.load(XFalse))
-        else:
+        elif IfType == "if_exp":
             tl.store(Ret, tl.load(XTrue)) if pid % 2 else tl.store(Ret, tl.load(XFalse))
+        elif IfType == "if_and":
+            if BoolVar and pid % 2 == 0:
+                tl.store(Ret, tl.load(XTrue))
+            else:
+                tl.store(Ret, tl.load(XFalse))
 
     cond = torch.ones(1, dtype=torch.int32, device='cuda')
     x_true = torch.tensor([3.14], dtype=torch.float32, device='cuda')
     x_false = torch.tensor([1.51], dtype=torch.float32, device='cuda')
     ret = torch.empty(1, dtype=torch.float32, device='cuda')
-    kernel[(1,)](cond, x_true, x_false, ret, if_type)
+    kernel[(1,)](cond, x_true, x_false, ret, if_type, True)
+    assert torch.equal(ret, x_true)
 
 
 def test_num_warps_pow2():