[prev in list] [next in list] [prev in thread] [next in thread] 

List:       sbcl-commits
Subject:    [Sbcl-commits] master: Micro-optimizations in MOVE-IMMEDIATE and MOVE-ARG on x86-64
From:       "Lutz Euler" <leuler () users ! sourceforge ! net>
Date:       2012-04-25 22:50:16
Message-ID: E1SNB2R-0001yW-Ti () sfs-ml-3 ! v29 ! ch3 ! sourceforge ! com
[Download RAW message or body]

The branch "master" has been updated in SBCL:
       via  c50747a96774ec8164ead5e51d74a6d8bcf6e822 (commit)
      from  ba0c7755846d3efe297d3b02b792381bc6c36515 (commit)

- Log -----------------------------------------------------------------
commit c50747a96774ec8164ead5e51d74a6d8bcf6e822
Author: Lutz Euler <lutz.euler@freenet.de>
Date:   Thu Apr 26 00:49:06 2012 +0200

    Micro-optimizations in MOVE-IMMEDIATE and MOVE-ARG on x86-64
    
    In MOVE-IMMEDIATE, when the target is in memory, avoid using a temporary
    register for more values than currently: The MOV instruction can move
    immediate values of type (SIGNED-BYTE 32) into 64-bit memory locations,
    not only (SIGNED-BYTE 31).
    
    Simplify a TYPE-CASE in MOVE-ARG: merge two clauses that generated
    exactly the same MOV instruction; spare a call to MOVE-IMMEDIATE and
    get rid of two ugly literal 29s thereby.
    
    Add a test.
---
 src/compiler/x86-64/move.lisp |    6 ++----
 tests/compiler.pure.lisp      |   18 ++++++++++++++++++
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/compiler/x86-64/move.lisp b/src/compiler/x86-64/move.lisp
index 7872710..cc0a777 100644
--- a/src/compiler/x86-64/move.lisp
+++ b/src/compiler/x86-64/move.lisp
@@ -129,7 +129,7 @@
           (sc-is target signed-reg unsigned-reg descriptor-reg any-reg))
      (inst mov target val))
     ;; Likewise if the value is small enough.
-    ((typep val '(signed-byte 31))
+    ((typep val '(signed-byte 32))
      (inst mov target val))
     ;; Otherwise go through the temporary register
     (tmp-tn
@@ -159,10 +159,8 @@
              (etypecase val
                ((integer 0 0)
                 (zeroize y))
-               ((or (signed-byte 29) (unsigned-byte 29))
-                (inst mov y (fixnumize val)))
                (integer
-                (move-immediate y (fixnumize val)))
+                (inst mov y (fixnumize val)))
                (symbol
                 (load-symbol y val))
                (character
diff --git a/tests/compiler.pure.lisp b/tests/compiler.pure.lisp
index fe4bd64..68b37d1 100644
--- a/tests/compiler.pure.lisp
+++ b/tests/compiler.pure.lisp
@@ -4236,3 +4236,21 @@
           (unless (= (funcall fun 16) (logand 15 (1- (ash 1 width))))
             (push (cons width extra) result)))))
     (assert (null result))))
+
+;; On x86-64 MOVE-IMMEDIATE of fixnum values into memory either directly
+;; uses a MOV into memory or goes through a temporary register if the
+;; value is larger than a certain number of bits. Check that it respects
+;; the limits of immediate arguments to the MOV instruction (if not, the
+;; assembler will fail an assertion) and doesn't have sign-extension
+;; problems. (The test passes fixnum constants through the MOVE VOP
+;; which calls MOVE-IMMEDIATE.)
+(with-test (:name :constant-fixnum-move)
+  (let ((f (compile nil `(lambda (g)
+                           (funcall g
+                                    ;; The first three args are
+                                    ;; uninteresting as they are
+                                    ;; passed in registers.
+                                    1 2 3
+                                    ,@(loop for i from 27 to 32
+                                            collect (expt 2 i)))))))
+    (assert (every #'plusp (funcall f #'list)))))

-----------------------------------------------------------------------


hooks/post-receive
-- 
SBCL

------------------------------------------------------------------------------
Live Security Virtual Conference
Exclusive live event will cover all the ways today's security and 
threat landscape has changed and how IT managers can respond. Discussions 
will include endpoint security, mobile security and the latest in malware 
threats. http://www.accelacomm.com/jaw/sfrnl04242012/114/50122263/
_______________________________________________
Sbcl-commits mailing list
Sbcl-commits@lists.sourceforge.net
https://lists.sourceforge.net/lists/listinfo/sbcl-commits
[prev in list] [next in list] [prev in thread] [next in thread]