From 38a723a307b722671d2beba0d034d57274517aa6 Mon Sep 17 00:00:00 2001
From: "Guillermo J. Rozas" <edu/mit/csail/zurich/gjr>
Date: Fri, 28 Aug 1987 21:54:15 +0000
Subject: [PATCH] Define with-temporary-register-copy! for 3 operand
instructions.
---
v7/src/compiler/back/lapgn2.scm | 46 ++++++++++++++++++++++-----------
1 file changed, 31 insertions(+), 15 deletions(-)
diff --git a/v7/src/compiler/back/lapgn2.scm b/v7/src/compiler/back/lapgn2.scm
index af6f50d3e..5a5ef7f9e 100644
--- a/v7/src/compiler/back/lapgn2.scm
+++ b/v7/src/compiler/back/lapgn2.scm
@@ -1,6 +1,6 @@
#| -*-Scheme-*-
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/back/lapgn2.scm,v 1.4 1987/08/28 18:51:09 jinx Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/back/lapgn2.scm,v 1.5 1987/08/28 21:54:15 jinx Exp $
Copyright (c) 1987 Massachusetts Institute of Technology
@@ -152,31 +152,47 @@ MIT in each case. |#
(else (register->register-transfer alias target))))
(register-reference target))))))
+;; These procedures are used when the copy is going to be transformed,
+;; and the machine has 3 operand instructions, which allow an implicit
+;; motion in the transformation operation.
+;; For example, on the DEC VAX it is cheaper to do
+;; bicl3 op1,source,target
+;; than
+;; movl source,target
+;; bicl2 op1,target
+;; The extra arguments are
+;; REC1, invoked if we are resuing an alias of source.
+;; It already contains the data to operate on.
+;; REC2, invoked if a `brand-new' alias for target has been allocated.
+;; We must take care of moving the data ourselves.
+
(define (with-register-copy-alias! source type target rec1 rec2)
- ;; REC1 is invoked if we are resuing an alias of source.
- ;; It already contains the data to operate on.
- ;; REC2 is invoked if a `brand-new' alias for target has been allocated.
- ;; We must take care of moving the data ourselves.
- ;; This procedure should be used when the copy is going to be transformed,
- ;; and the machine has 3 operand instructions, which allow an
- ;; implicit motion in the transformation operation.
- ;; For example, on the DEC VAX it is cheaper to do
- ;; bicl3 op1,source,target
- ;; than
- ;; movl source,target
- ;; bicl2 op1,target
+ (provide-copy-reusing-alias! source type rec1 rec2
+ (lambda (reusable-alias)
+ (add-pseudo-register-alias! target reusable-alias false))
+ (lambda ()
+ (allocate-alias-register! target type))))
+
+(define (with-temporary-register-copy! register type rec1 rec2)
+ (provide-copy-reusing-alias! register type rec1 rec2
+ need-register!
+ (lambda ()
+ (allocate-temporary-register! type))))
+
+(define (provide-copy-reusing-alias! source type rec1 rec2 if-reusable if-not)
+ ;; IF-NOT is assumed to return a machine register.
(let ((reusable-alias
(and (dead-register? source)
(register-alias source type))))
(if reusable-alias
(begin (delete-dead-registers!)
- (add-pseudo-register-alias! target reusable-alias false)
+ (if-reusable reusable-alias)
(rec1 (register-reference reusable-alias)))
(let ((alias (if (machine-register? source)
source
(register-alias source false))))
(delete-dead-registers!)
- (let ((target (allocate-alias-register! target type)))
+ (let ((target (if-not)))
(cond ((not alias)
(rec2 (pseudo-register-home source)
(register-reference target)))
--
2.25.1