The schemify pass collects known-value information as the first step
of processing a linklet body, but the main pass to process the linklet
body may simplify it in a way that exposes new information. For
example, in
(define (call) (values 1 2))
(define-values (x y) (call))
the main pass will inline `call` and expose the fact that `x` and `y`
are always 1 and 2, respectively.
Adjust schemify to inspect the simplified form of a definition and
potentially add new information to known-value information, which is
useful later in the ame linklet body and also as cross-module
information.
Like other optimizations that schemify duplicates, constant folding
helps support cross-module optimization. Related "no-prompt"
declarations for primitives can reduce `call-with-module-prompt`s in
schemified output, too, which can interfere with Chez Scheme's
optimizer.
This is probably related to #2712.
It's the only occurrence of SCHEME_NO_EXN pointing to the fact that
this is an historical artifact that can be removed.
Recognize `(define-values (id ...) (values rhs ...))` and split to
multiple `define`s after simplifying the right-hand side of
`define-values`. Also, don't split if a define variable is referenced
too early.
Adding return statement where it doesn't exist, causes problems with
functions marked no return so it should be avoided.
Related to #2709 - with this PR, clang won't complain any longer
about issues with xform generated sources about functions marked
no return that do indeed return.
The fact that Racket uses double hashing and Racket CS uses single
hashing can show up in a test that supplies a `equal-key-proc`
argument to `{impersonate,chaperone}-hash`.
When `set!` is used to tie a recursove knot in a flattened linklet,
the expander can recognize that pattern and not complain that a
mutable variable might be shared across places. Improving that
inference means fewer `++global-ok` flags in Makefiles.
This commit also avoids single-quote as an escaping form in a
makefile, which doesn't work with nmake on Windows.
