Fix bug in `instruction-dead?': an assignment whose RHS contains side

effects cannot be considered dead.

diff --git a/v7/src/compiler/rtlopt/rlife.scm b/v7/src/compiler/rtlopt/rlife.scm
index 9aaf0bf7bee4f7766dcb8a064abf0fe573ecd615..435c109a2b8849ab96e3edf021532b6d4000cbe8 100644 (file)
--- a/v7/src/compiler/rtlopt/rlife.scm
+++ b/v7/src/compiler/rtlopt/rlife.scm
@@ -1,6 +1,6 @@
 #| -*-Scheme-*-
 
-$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/rtlopt/rlife.scm,v 1.59 1988/06/14 08:44:45 cph Exp $
+$Header: /Users/cph/tmp/foo/mit-scheme/mit-scheme/v7/src/compiler/rtlopt/rlife.scm,v 1.60 1988/12/15 17:27:22 cph Rel $
 
 Copyright (c) 1987 Massachusetts Institute of Technology
 
@@ -37,9 +37,7 @@ MIT in each case. |#
 
 (declare (usual-integrations))
 \f
-(package (lifetime-analysis mark-set-registers!)
-
-(define-export (lifetime-analysis rgraphs)
+(define (lifetime-analysis rgraphs)
   (for-each walk-rgraph rgraphs))
 
 (define (walk-rgraph rgraph)
@@ -113,9 +111,9 @@ MIT in each case. |#
            (for-each-regset-member old register-crosses-call!))
        (if (instruction-dead? rtl old)
            (set-rinst-rtl! rinst false)
-           (begin (update-live-registers! old dead live rtl bblock rinst)
-                  (for-each-regset-member old
-                    increment-register-live-length!))))))
+           (begin
+             (update-live-registers! old dead live rtl bblock rinst)
+             (for-each-regset-member old increment-register-live-length!))))))
   (bblock-perform-deletions! bblock))
 
 (define (propagation-loop bblock procedure)
@@ -181,10 +179,10 @@ MIT in each case. |#
         (and (rtl:register? address)
              (let ((register (rtl:register-number address)))
                (and (pseudo-register? register)
-                    (not (regset-member? needed register))))))))
+                    (not (regset-member? needed register))))))
+       (not (rtl:expression-contains? (rtl:assign-expression rtl)
+                                     rtl:volatile-expression?))))
 
 (define (interesting-register? expression)
   (and (rtl:register? expression)
-       (pseudo-register? (rtl:register-number expression))))
-
-)
\ No newline at end of file
+       (pseudo-register? (rtl:register-number expression))))
\ No newline at end of file