bugMIT/GNU Scheme - Bugs: bug #27385, compiler still generates bad i386...

 
 

bug #27385: compiler still generates bad i386 code in the general case of FIXNUM-LSH, for negative arguments

Submitted by:  Taylor R. Campbell <riastradh>
Submitted on:  Sat 05 Sep 2009 06:37:02 AM UTC  
 
Category: compilerSeverity: 3 - Normal
Priority: 5 - NormalItem Group: Incorrect behavior
Status: FixedPrivacy: Public
Assigned to: Taylor R. Campbell <riastradh>Originator Name: 
Open/Closed: Closed
Keywords: 

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Fri 13 Nov 2009 10:10:24 PM UTC, comment #1:

Should be fixed in commit 1f62f5c1dc6575221159605ab72e44adcafdfe7b.

Taylor R. Campbell <riastradh>
Project MemberIn charge of this item.
Sat 05 Sep 2009 06:37:02 AM UTC, original submission:

All of the following should yield -1:

(fix:lsh -1 -1)
;Value: 33554431

(fix:lsh -1 -30)
;Value: 0

(fix:lsh -123 -30)
;Value: 0

This should yield -62:

(fix:lsh -123 -1)
;Value: 33554370

The general case is already so complex that it would probably be worthwhile just to bail and defer to the microcode primitive, but I don't think Liar can do that only for particular uses of primitives, and obviously we don't want to do that for every use of the FIXNUM-LSH primitive.

Taylor R. Campbell <riastradh>
Project MemberIn charge of this item.

 

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    Follow 5 latest changes.

    Date Changed By Updated Field Previous Value => Replaced By
    Fri 30 Aug 2013 06:17:22 PM UTCriastradhStatusReady For Test=>Fixed
      Assigned toNone=>riastradh
      Open/ClosedOpen=>Closed
    Fri 13 Nov 2009 10:10:24 PM UTCriastradhStatusNone=>Ready For Test
    Sat 05 Sep 2009 06:37:36 AM UTCriastradhSummarycompiler still generates bad code in the general case of FIXNUM-LSH, for negative arguments=>compiler still generates bad i386 code in the general case of FIXNUM-LSH, for negative arguments

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