From 0e838226c5b03f11e196a4c830655bbe9d019df4 Mon Sep 17 00:00:00 2001
From: Stephen Adams <edu/mit/csail/zurich/adams>
Date: Sat, 6 May 1995 18:25:35 +0000
Subject: [PATCH] Code for BEGIN now generates simpler code for sequences fo
`simple' expressions.
---
v8/src/compiler/midend/cpsconv.scm | 36 ++++++++++++++++++------------
1 file changed, 22 insertions(+), 14 deletions(-)
diff --git a/v8/src/compiler/midend/cpsconv.scm b/v8/src/compiler/midend/cpsconv.scm
index bec483ae0..a4eaedba7 100644
--- a/v8/src/compiler/midend/cpsconv.scm
+++ b/v8/src/compiler/midend/cpsconv.scm
@@ -1,6 +1,6 @@
#| -*-Scheme-*-
-$Id: cpsconv.scm,v 1.11 1995/05/05 12:57:26 adams Exp $
+$Id: cpsconv.scm,v 1.12 1995/05/06 18:25:35 adams Exp $
Copyright (c) 1994-1995 Massachusetts Institute of Technology
@@ -297,19 +297,27 @@ MIT in each case. |#
(internal-error "Empty begin")
(let walk ((next (car actions))
(actions (cdr actions)))
- (if (null? actions)
- (cpsconv/expr cont next)
- (let ((next-name (cpsconv/new-name 'NEXT))
- (ignore (cpsconv/new-ignored-continuation)))
- `(LET ((,next-name
- (LAMBDA (,ignore)
- ,(walk (car actions)
- (cdr actions)))))
- ,(cpsconv/expr
- (cpsconv/begin-continuation
- next-name
- (cpsconv/dbg-continuation/make 'BEGIN form next))
- next)))))))
+ (cond ((null? actions)
+ (cpsconv/expr cont next))
+ ((form/simple? next)
+ ;; This clause is completely optional but makes for a smaller
+ ;; program that needs less simplification.
+ (let ((next* (cpsconv/simple/copy next))
+ (rest (walk (car actions) (cdr actions))))
+ (if (BEGIN/? rest)
+ `(BEGIN ,next* ,@(begin/exprs rest))
+ `(BEGIN ,next* ,rest))))
+ (else
+ (let ((next-name (cpsconv/new-name 'NEXT)))
+ `(LET ((,next-name
+ (LAMBDA (,(cpsconv/new-ignored-continuation))
+ ,(walk (car actions)
+ (cdr actions)))))
+ ,(cpsconv/expr
+ (cpsconv/begin-continuation
+ next-name
+ (cpsconv/dbg-continuation/make 'BEGIN form next))
+ next))))))))
(define-cps-converter IF (cont pred conseq alt)
(define (general)
--
2.25.1