Optimize `1+' and `1-' on fixnums.

* libguile/vm-i-scheme.c (INUM_MAX, INUM_MIN): New macros.
  (add1, sub1): Add/subtract without untagging the operand.  This leads
  to a 44% run time improvement compared to the previous
  implementation.

* libguile/vm.c: Include <stdint.h>.

* test-suite/tests/numbers.test ("1+", "1-"): Add tests for
  MOST-POSITIVE-FIXNUM, resp. MOST-NEGATIVE-FIXNUM, for 32-bit and
  34-bit values thereof.

* benchmark-suite/benchmarks/arithmetic.bm: New file.

* benchmark-suite/Makefile.am (SCM_BENCHMARKS): Add it.

2 files changed, 47 insertions, 0 deletions

diff --git a/benchmark-suite/Makefile.am b/benchmark-suite/Makefile.am
index e2aad9148..63f490cd4 100644
--- a/benchmark-suite/Makefile.am
+++ b/benchmark-suite/Makefile.am
@@ -1,4 +1,5 @@
 SCM_BENCHMARKS = benchmarks/0-reference.bm		\
+		 benchmarks/arithmetic.bm		\
 		 benchmarks/bytevectors.bm		\
 		 benchmarks/chars.bm			\
 		 benchmarks/continuations.bm		\
diff --git a/benchmark-suite/benchmarks/arithmetic.bm b/benchmark-suite/benchmarks/arithmetic.bm
new file mode 100644
index 000000000..cd8bbbd7b
--- /dev/null
+++ b/benchmark-suite/benchmarks/arithmetic.bm
@@ -0,0 +1,46 @@
+;;; -*- mode: scheme; coding: utf-8; -*-
+;;; Integer arithmetic.
+;;;
+;;; Copyright 2010 Free Software Foundation, Inc.
+;;;
+;;; This program is free software; you can redistribute it and/or
+;;; modify it under the terms of the GNU Lesser General Public License
+;;; as published by the Free Software Foundation; either version 3, or
+;;; (at your option) any later version.
+;;;
+;;; This program is distributed in the hope that it will be useful,
+;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;;; GNU Lesser General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU Lesser General Public
+;;; License along with this software; see the file COPYING.LESSER.  If
+;;; not, write to the Free Software Foundation, Inc., 51 Franklin
+;;; Street, Fifth Floor, Boston, MA 02110-1301 USA
+
+(define-module (benchmarks arithmetic)
+  #:use-module (benchmark-suite lib))
+
+(define-syntax repeat
+  (lambda (s)
+    ;; Construct an expression of the form `(OP (OP (OP BODY)))', with a
+    ;; depth of COUNT.
+    (syntax-case s ()
+      ((_ op body count)
+       (number? (syntax->datum #'count))
+       (let loop ((count  (syntax->datum #'count))
+                  (result #'body))
+         (if (= 0 count)
+             result
+             (loop (1- count)
+                   (with-syntax ((result result))
+                     #'(op result)))))))))
+
+
+(with-benchmark-prefix "fixnum"
+
+  (benchmark "1+" 1e7
+    (repeat 1+ 2 100))
+
+  (benchmark "1-" 1e7
+    (repeat 1- 2 100)))