In general, LLVM's parsing of decimal integers to `APInt`s forms an
`APInt` that is 4n bits wide, where n is the length of the integer, and
the `isNegative` check only checks the high bit.
In this case, we form an `APInt` that is four bits wide, with the high
bit set, which we reject because we think it's "negative". These two
array lengths are the only ones where this happens -- if the decimal
integer value is two characters long, we form an `APInt` that is eight
bits wide but holds a value < 100, so the high bit is never set, and the
same applies for longer integers too.
An `IntegerLiteral` is never negative, so we don't need the `isNegative`
check, and in fact it only detects the n=8 and n=9 cases.
Continuing with #3070. Just a dir and file rename (mostly removing
prefixes, although for parse_tree_fuzzer and parse_tree_file_test I'm
dropping "tree" instead of "parse"). Everything in the parse dir should
be marked as a move.
Continuing along with #3070. Note this is just a file rename, with BUILD
edits; every file previously in semantics/ should show as moved (except
maybe BUILDs, which split).
Richard Smith
Geoff Romer
Jon Ross-Perkins