[Bug middle-end/44203] New: [4.6 regression] New prefetch test failures

[Bug middle-end/44203] New: [4.6 regression] New prefetch test failures

[hjl dot tools at gmail dot com]

On Linux/x86, revision 159557:

http://gcc.gnu.org/ml/gcc-cvs/2010-05/msg00609.html

caused:

FAIL: gcc.dg/tree-ssa/prefetch-3.c scan-tree-dump-times aprefetch "unroll
factor 4" 1
FAIL: gcc.dg/tree-ssa/prefetch-5.c scan-tree-dump-times aprefetch "Issued
prefetch" 2
FAIL: gcc.dg/tree-ssa/prefetch-6.c scan-assembler-times prefetchnta 3
FAIL: gcc.dg/tree-ssa/prefetch-6.c scan-tree-dump-times aprefetch "Issued
nontemporal prefetch" 3
FAIL: gcc.dg/tree-ssa/update-unroll-1.c scan-tree-dump-not aprefetch "SUCC: 7
.100.0%"


-- 
           Summary: [4.6 regression] New prefetch test failures
           Product: gcc
           Version: 4.6.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: hjl dot tools at gmail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[borntraeger at de dot ibm dot com]

------- Comment #1 from borntraeger at de dot ibm dot com  2010-05-20 08:29 -------

Indeed. I think I found a typo when handling array prefetches.
a potential fix might be:

--- gcc/tree-ssa-loop-prefetch.c        (Revision 159557)
+++ gcc/tree-ssa-loop-prefetch.c        (Arbeitskopie)
@@ -440,7 +440,7 @@

       *ar_data->step = fold_build2 (MULT_EXPR, sizetype,
                                    fold_convert (sizetype, *ar_data->step),
-                                   fold_convert (sizetype, step));
+                                   fold_convert (sizetype, stepsize));
       idelta *= imult;
     }



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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[rguenth at gcc dot gnu dot org]

-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.6.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[borntraeger at de dot ibm dot com]

------- Comment #2 from borntraeger at de dot ibm dot com  2010-05-20 12:28 -------
Created an attachment (id=20709)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20709&action=view)
new version of the fix. 

There is actually a second bug :-(
We not only have to replace step with stepsize (a=a+b*b vs. a=a+b*c)
we also have to fix the fact that we changed a=a+b*c to a=(a+b)*c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[hjl dot tools at gmail dot com]

------- Comment #3 from hjl dot tools at gmail dot com  2010-05-22 00:12 -------
(In reply to comment #2)
> Created an attachment (id=20709)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=20709&action=view) [edit]
> new version of the fix. 
> 
> There is actually a second bug :-(
> We not only have to replace step with stepsize (a=a+b*b vs. a=a+b*c)
> we also have to fix the fact that we changed a=a+b*c to a=(a+b)*c
> 

This works for me on Linux/x86-64.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[krebbel at gcc dot gnu dot org]

------- Comment #4 from krebbel at gcc dot gnu dot org  2010-05-25 11:18 -------
Subject: Bug 44203

Author: krebbel
Date: Tue May 25 11:18:07 2010
New Revision: 159816

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=159816
Log:
2010-05-25  Christian Borntraeger  <borntraeger@de.ibm.com>

        PR 44203
        * tree-ssa-loop-prefetch.c: Fix logic for step calculation to
        match the original (and intended) behaviour before r159557.  This
        changeset changed a=a+b*c to a=(a+b)*b which was obviously wrong
        in two ways.


Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/tree-ssa-loop-prefetch.c


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[jakub at gcc dot gnu dot org]

------- Comment #5 from jakub at gcc dot gnu dot org  2010-06-24 11:24 -------
Is this now fixed?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[borntraeger at de dot ibm dot com]

------- Comment #6 from borntraeger at de dot ibm dot com  2010-06-24 12:35 -------
HJ confirmed that the patch worked and Andreas applied the patch. So from my
point of view, the problem is fixed.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203

[Bug middle-end/44203] [4.6 regression] New prefetch test failures

[jakub at gcc dot gnu dot org]

------- Comment #7 from jakub at gcc dot gnu dot org  2010-06-29 15:43 -------
Fixed then.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44203