When a literal is used on the left-hand side of a numeric operator,
Python is able to constant-fold some expressions:
>>> dis.dis(lambda x: 0 + 0 + x)
1 0 LOAD_CONST 1 (0)
2 LOAD_FAST 0 (x)
4 BINARY_ADD
6 RETURN_VALUE
If a literal is used on the right-hand side such that the left-hand
side is variable, this doesn't happen:
>>> dis.dis(lambda x: x + 0 + 0)
1 0 LOAD_FAST 0 (x)
2 LOAD_CONST 1 (0)
4 BINARY_ADD
6 LOAD_CONST 1 (0)
8 BINARY_ADD
10 RETURN_VALUE
PyRTL generates fairly redundant code due to the pervasive masking,
and because of that, transforming expressions into the former form,
where possible, improves runtime by about 10% on Minerva SRAM SoC.
