I found that AMD Radeon RX 6400 mis-optimizes another HLSL pixel shader program. The expected output is a white screen, but the wrong optimization causes the output color to be black. After manual debugging the compiled binary executable, I found that the compiler incorrectly optimizes the statement "c = 0.09 - h * h" to be "c = 0.09 - h". The runtime value of c is 0.1, so the correct computation should be "c = 0.09 - 0.1 * 0.1 = 0.08", but after the wrong optimization, the statement execution becomes "c = 0.09 - 0.1 = -0.01".
The code and the explanation of the code can be found in: