change some float to half,mali offline compiler report stack spilling

Hi guys,

I write a TAA shader in unity,I try to optimization this shader,change some float to half.

then I compare the shader brfore and after with mali offline compiler

Mali-G76 before,no spilling

Mali-G76 after,spilling

Mali-G77 before,spilling

Mali-G77 after,no spilling

2 questions:

1.Why the results of Mali-G76 and Mali-G77 are opposite

2.Why do I reduce the calculation precision, but it spilling on Mali-G76