Revert "[BACKEND] Various bug fixes; making reductions faster (#533)".

This is a more stable commit that produce bitwise identical code to earlier
versions. Using commits after this one may lead to slightly different numerics

python/test/unit/language/test_core.py

@@ -698,7 +698,6 @@ def test_reduce1d(dtype_str, shape, device='cuda'):
 
     rs = RandomState(17)
     x = numpy_random((shape,), dtype_str=dtype_str, rs=rs)
-    x[:] = 1
     # numpy result
     z_ref = np.sum(x).astype(getattr(np, dtype_str))
     # triton result
@@ -1133,25 +1132,3 @@ def test_constexpr_shape():
     x_tri = to_triton(np.empty((256, ), dtype=np.int32))
     kernel[(1,)](x_tri)
     np.testing.assert_equal(to_numpy(x_tri), np.arange(0, 256))
-
-# -------------
-# test if
-# -------------
-
-
-def test_if():
-
-    @triton.jit
-    def kernel(Cond, XTrue, XFalse, Ret):
-        pid = tl.program_id(0)
-        cond = tl.load(Cond)
-        if pid % 2:
-            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)