[Bug Report] Invalid rounding with reduce_tile REDUCE_SCALAR

[hschoi4448]

Describe the bug
While debugging recently, I noticed that the result of reduce_scalar seemed strange, and I discovered unusual behavior.

The result of the reduce operation varies depending on the position of the values.

    constexpr auto cb_in0 = tt::CBIndex::c_0;
    {
        cb_reserve_back(cb_in0, 1);
        float* ptr = reinterpret_cast<float*>(get_write_ptr(cb_in0));
        memset(ptr, 0, 1024 * sizeof(float));
        // this case result is 2.0
        ptr[0] = 1.0019531;
        ptr[16] = 1.0f;

        // this case result is 2.0019531250
        // ptr[0] = 1.0019531;
        // ptr[1] = 1.0f;

        cb_push_back(cb_in0, 1);
    }

    {
        constexpr auto cb_in2 = tt::CBIndex::c_2;
        cb_reserve_back(cb_in2, 1);
        float* ptr = reinterpret_cast<float*>(get_write_ptr(cb_in2));
        memset(ptr, 0, 1024 * sizeof(float));
        for (int i = 0; i < 1024; i++) {
            ptr[i] = 1;
        }
        cb_push_back(cb_in2, 1);
    }

I prepared both the data and scalar values in the reader kernel for the reduce operation. And the scalar CB values are all filled with 1.0f.
The test was conducted by adding the values 1.0019531 and 1.0.

if ptr[0] = 1.0019531, ptr[16] = 1.0. than reduce result is 2.0.
if ptr[0] = 1.0019531, ptr[1] = 1.0. than reduce result is 2.0019531250

I think that the fact the position of the values affects the result is a bug.

• If there were many values, it would be understandable that the calculation order could affect the result. However, since there are only two values, it’s odd that the order has an impact on the result.

related kernel code:

• https://github.com/tenstorrent/tt-metal/blob/hyungsuk/reduce_bug_example_scalar/ttnn/cpp/ttnn/operations/moreh/moreh_softmax/device/kernels/reader_moreh_softmax_w.cpp
• https://github.com/tenstorrent/tt-metal/blob/hyungsuk/reduce_bug_example_scalar/ttnn/cpp/ttnn/operations/moreh/moreh_softmax/device/kernels/moreh_softmax_w.cpp

To Reproduce
Steps to reproduce the behavior:

1. Go to https://github.com/tenstorrent/tt-metal/tree/hyungsuk/reduce_bug_example_scalar
2. Run cmd: pytest ./tests/ttnn/unit_tests/operations/test_moreh_softmax.py
3. See DPRINT result

Expected behavior
I hope the issue with the result can be fixed.

Screenshots
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Please complete the following environment information:

• OS: Ubuntu 22.04.4 LTS
• Version of software (eg. commit f191d02)
• Arch: wormhole_b0

Additional context
Add any other context about the problem here.