The strength reduction (SR) phase mishandled the END pseudo when SR
found at least 2 different expressions in the same loop, and SR made a
new header for the loop.
Since 1987 (commit 159b84e), SR appended the new header to the end of
the procedure. Later, SR fixed the header by adding a BRA branch to
the loop's entry, and moving the END pseudo from the previous basic
block to the header. If SR found multiple expressions, it called
fix_header() multiple times, and tried to move the END again. The
extra move failed assert(INSTR(e) == ps_end), or moved another line
after the END, so opt2 (the peephole optimizer) would crash.
Fix by removing fix_header() and moving the code to make_header(), so
SR adds the BRA and moves the END when it makes the header, and does
so only once for each header.
Adjust init_code(), which inserts code into a header. Stop checking
for an empty header, because make_header() now adds BRA. After
inserting code before BRA, don't move LP_INSTR, because later
insertions should go before BRA, not after END.
Most warnings are for functions implicitly returning int. Change most
of these functions to return void. (Traditional K&R C had no void
type, but C89 has it.)
Add prototypes to most function declarations in headers. This is
easy, because ego declares most of its extern functions, and the
comments listed most parameters. There were a few outdated or missing
declarations, and a few .c files that failed to include an .h with the
declarations.
Add prototypes to a few function definitions in .c files. Most
functions still have traditional K&R definitions. Most STATIC
functions still don't have prototypes, because they have no earlier
declaration where I would have added the prototype.
Change some prototypes in util/ego/share/alloc.h. Functions newmap()
and oldmap() handle an array of pointers to something; change the
array's type from `short **` to `void **`. Callers use casts to go
between `void **` and the correct type, like `line_p *`. Function
oldtable() takes a `short *`, not a `short **`; I added the wrong type
in 5bbbaf4.
Make a few other changes to silence warnings. There are a few places
where clang wants extra parentheses in the code.
Edit util/ego/ra/build.lua to add the missing dependency on ra*.h; I
needed this to prevent crashes from ra.
