compiler: optimization control.

* lisplib.c (compiler_set_entries): Register *opt-level*
symbol for auto-loading.

* share/txr/stdlib/compiler.tl (*opt-level*): New special
variable.
(compiler comp-let): Eliminate frames only at level 3.
(compiler comp-lambda-impl): Lift load time at level 3.
(compiler comp-arith-form): Constant-folding only at lvl 1.
(compiler comp-fun-form): Algebraic substitutions and
reductions and constant-folding only at level 1.
(compiler comp-apply-call): Constant folding at level 1.
(compiler optimize): Optimizations off if level zero.
Thread jumps and eliminate dead code at level 2.
Flow-analysis based optimizations at level 3.
Additional optimizations at level 4.
(compile comp-block): Block elimination at level 3.
(compile-toplevel): Rebind *opt-level*, giving it value zero
if it is previously nil.

* share/txr/stdlib/optimize.tl (basic-blocks get-insns): Just
retrieve the instructions, letting caller decide whether to
call late-peephole or not.

* txr.1: Documented *opt-level*.

1 files changed, 1 insertions, 0 deletions

diff --git a/lisplib.c b/lisplib.c
index 79c7087b..a425d95b 100644
--- a/lisplib.c
+++ b/lisplib.c
@@ -724,6 +724,7 @@ static val compiler_set_entries(val dlt, val fun)
     lit("compile-toplevel"), lit("compile"), lit("compile-file"),
     lit("compile-update-file"),
     lit("with-compilation-unit"), lit("dump-compiled-objects"),
+    lit("*opt-level*"),
     nil
   };