Some LIR Operations with only one input are currently implemented as LIR_Op2 and the 2nd input operand is misused for temp registers: lir_sqrt, lir_abs, lir_neg, lir_f2hf, lir_hf2f
This results in unnecessary "live_in" effects for temp registers and requires workarounds like code which initializes a temp register.
A better solution would be to use LIR_Op1 with one temp operand.
In addition, lir_tan and lir_log10 are no longer used and the corresponding dead code can be removed.