Fix a bug when pmie evaluates rules that make multiple references
to a single constant, where it was incorrectly folding a constant
after the first use. Corruption of pmie's address space results,
when subsequent rules make use of the folded constant expression,
which has been observed as causing SIGSEGVs, infinite loops, and
other random wierdness.
Fix pmie constant folding
Fix a bug when pmie evaluates rules that make multiple references
to a single constant, where it was incorrectly folding a constant
after the first use. Corruption of pmie's address space results,
when subsequent rules make use of the folded constant expression,
which has been observed as causing SIGSEGVs, infinite loops, and
other random wierdness.