* module/language/cps/simplify.scm (prune-continuations): Prune
continuations as a post-pass with a fresh DFG. Using a
pre-eta-conversion DFG as we were doing before missed some cases.
* module/language/cps/simplify.scm (compute-eta-reductions): Avoid
trying to eta-reduce a jump-to-self, as in (let lp () (lp)). This
caused the compiler to hang.
* module/language/cps.scm ($callk): New expression type, for calls to
known labels. Part of "low CPS".
* module/language/cps/arities.scm:
* module/language/cps/closure-conversion.scm:
* module/language/cps/compile-bytecode.scm:
* module/language/cps/dce.scm:
* module/language/cps/dfg.scm:
* module/language/cps/effects-analysis.scm:
* module/language/cps/simplify.scm:
* module/language/cps/slot-allocation.scm:
* module/language/cps/verify.scm: Adapt call sites.
* libguile/vm-engine.c (call-label, tail-call-label): New instructions.
Renumber the rest; this is an ABI change.
* libguile/_scm.h (SCM_OBJCODE_MINOR_VERSION):
* module/system/vm/assembler.scm (*bytecode-minor-version*): Bump.
* doc/ref/compiler.texi (CPS in Guile): Document $callk.
