[Bug middle-end/31699] New: [Regression 4.3] -march=opteron -ftree-vectorize generates wrong code

[Bug middle-end/31699] New: [Regression 4.3] -march=opteron -ftree-vectorize generates wrong code

[burnus at gcc dot gnu dot org]

This is with the Polyhedron rnflow.f90 test case
(http://www.polyhedron.co.uk/pb05/polyhedron_benchmark_suite.html)

It was working on 2007-04-23 (should be r124055) and started to fail since
2007-04-24 (should be r124093). (Same with PR 31697)

Crash after 1.5 seconds with
  gfortran -m32 -march=opteron -ftree-vectorize -O2 rnflow.f90

Same crash with -m64.

no crash:
- without: -march=opteron
- without: -ftree-vectorize
- with: -O1

Program received signal SIGSEGV, Segmentation fault.
#0  0x00000000004058a9 in invima (__result=<value optimized out>,
a=0x2ac0ff48d010, j=@0x7fffac442b18, k=<value optimized out>,
    m=@0x7fffac442b1c) at rnflow.f90:2904
#1  0x0000000000407446 in evlrnf_ (ptrs0t=<value optimized out>, nclsm=<value
optimized out>, prnf0t=0xdaf380) at rnflow.f90:2771

  2899        elseif (n > 1) then
  2900           allocate (da (1:n,1:n))
  2901           lw = n * m
  2902           allocate (dw (1:lw))
  2903           allocate (ipivt (1:n))
  2904           da (1:n, 1:n) = - a (j:k-1, j:k-1)
  2905           do i = 1, n
  2906              da (i, i) = da (i, i) + 1.0d0
  2907           enddo


-- 
           Summary: [Regression 4.3] -march=opteron -ftree-vectorize
                    generates wrong code
           Product: gcc
           Version: 4.3.0
            Status: UNCONFIRMED
          Keywords: wrong-code
          Severity: normal
          Priority: P3
         Component: middle-end
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: burnus at gcc dot gnu dot org
GCC target triplet: x86_64-unknown-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [Regression 4.3] -march=opteron -ftree-vectorize generates wrong code

[jb at gcc dot gnu dot org]

------- Comment #1 from jb at gcc dot gnu dot org  2007-04-26 10:36 -------
Confirmed. It occurs also on i686-pc-linux-gnu.

My observations:

- -march specific optimizations do not seem to have any effect. What does have
an effect is that on i686-pc-linux-gnu I need either -march= or -msse2 or else
the vectorizer is disabled.

- Like you, crash occurs with -O2 and -O3, not -O1

I.e. lowest optimization that triggers the bug for me is "-O2 -msse2
-ftree-vectorize".


-- 

jb at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jb at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2007-04-26 10:36:01
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [Regression 4.3] -march=opteron -ftree-vectorize generates wrong code

[ubizjak at gmail dot com]

------- Comment #2 from ubizjak at gmail dot com  2007-04-26 11:20 -------
This bug is due to my commit:

http://gcc.gnu.org/ml/gcc-cvs/2007-04/msg00657.html

This patch introduces "vec_unpacks_hi_v4sf" and "vec_unpacks_lo_v4sf" to sse.md
an these patterns trigger generic vectorizer problem (related to multiple data
types in the loop having VEC_UNPAC_HI/LO and not related to convesions at all)
in alignment handling.

Polyhedron crashes in:

Dump of assembler code from 0x804def2 to 0x804dff2:
>>  0x0804def2 <invima+594>:        movapd %xmm1,(%eax)
    0x0804def6 <invima+598>:        cvtps2pd 0xffffff48(%ebp),%xmm0
    0x0804defd <invima+605>:        movapd %xmm0,0x10(%eax)
    0x0804df02 <invima+610>:        add    $0x20,%eax
    0x0804df05 <invima+613>:        cmp    %edi,%ebx

Dorit has confirmed the problem and she is already testing a fix.

The C testcase that crashes (you need -O2 -msse2 -ftree-vectorize [-m32]) to
trigger the problem, as "z" needs to be aligned to 8 bytes:

--cut here--
float x[256];

void foo(void)
{
 double *z = malloc (sizeof(double) * 256);

 int i;
 for (i=0; i<256; ++i)
   z[i] = x[i] + 1.0f;
}


int main()
{
 int i;

 for (i = 0; i < 256; i++)
   x[i] = (float) i;

 foo();

 return 0;
}
--cut here--

If an urgent fix is needed, then simply rename "vec_unpacks_hi_v4sf" to
"*vec_unpacks_hi_v4sf".


-- 

ubizjak at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |dorit at il dot ibm dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [Regression 4.3] -march=opteron -ftree-vectorize generates wrong code

[dorit at il dot ibm dot com]

------- Comment #3 from dorit at il dot ibm dot com  2007-04-26 19:34 -------
Created an attachment (id=13450)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13450&action=view)
patch


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [Regression 4.3] -march=opteron -ftree-vectorize generates wrong code

[dorit at il dot ibm dot com]

------- Comment #4 from dorit at il dot ibm dot com  2007-04-26 19:37 -------
I'm testing the attched patch. The problem is that we don't compute the peel
factor correctly (when peeling to align a store) when we have multiple
data-types in the loop (the computation assumes that VF is the number of
elements in a vector, but that doesn't hold for all the datarefs in the loop if
their types are of different sizes)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [Regression 4.3] -march=opteron -ftree-vectorize generates wrong code

[ubizjak at gmail dot com]

------- Comment #5 from ubizjak at gmail dot com  2007-04-27 11:35 -------
(In reply to comment #3)
> Created an attachment (id=13450)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13450&action=view) [edit]

This patch fixes the testcase from comment #2 and Polyhedron rnflow failure in
both 32bit (-m32 -msse2) and 64bit modes. The loop is still vectorized and
cvtps2pd insns are still present in the asm dump.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [4.3 Regression] -march=opteron -ftree-vectorize generates wrong code

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |pinskia at gcc dot gnu dot
                   |                            |org
            Summary|[Regression 4.3] -          |[4.3 Regression] -
                   |march=opteron -ftree-       |march=opteron -ftree-
                   |vectorize generates wrong   |vectorize generates wrong
                   |code                        |code
   Target Milestone|---                         |4.3.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [4.3 Regression] -march=opteron -ftree-vectorize generates wrong code

[dorit at il dot ibm dot com]

------- Comment #6 from dorit at il dot ibm dot com  2007-05-02 20:38 -------
patch: http://gcc.gnu.org/ml/gcc-patches/2007-05/msg00111.html


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [4.3 Regression] -march=opteron -ftree-vectorize generates wrong code

[dorit at gcc dot gnu dot org]

------- Comment #7 from dorit at gcc dot gnu dot org  2007-05-03 13:55 -------
Subject: Bug 31699

Author: dorit
Date: Thu May  3 12:54:45 2007
New Revision: 124375

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=124375
Log:
        PR tree-optimization/31699
        * tree-vect-analyze.c (vect_update_misalignment_for_peel): Remove wrong
        code.
        (vect_enhance_data_refs_alignment): Compute peel amount using
        TYPE_VECTOR_SUBPARTS instead of vf.
        * tree-vect-transform.c (vect_gen_niters_for_prolog_loop): Likewise.


Added:
    trunk/gcc/testsuite/gcc.dg/vect/pr31699.c
    trunk/gcc/testsuite/gcc.dg/vect/vect-multitypes-11.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/vect/vect-floatint-conversion-1.c
    trunk/gcc/testsuite/gcc.dg/vect/vect-intfloat-conversion-1.c
    trunk/gcc/testsuite/gcc.dg/vect/vect-iv-4.c
    trunk/gcc/testsuite/gcc.dg/vect/vect-multitypes-1.c
    trunk/gcc/testsuite/gcc.dg/vect/vect-multitypes-4.c
    trunk/gcc/testsuite/lib/target-supports.exp
    trunk/gcc/tree-vect-analyze.c
    trunk/gcc/tree-vect-transform.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [4.3 Regression] -march=opteron -ftree-vectorize generates wrong code

[burnus at gcc dot gnu dot org]

------- Comment #8 from burnus at gcc dot gnu dot org  2007-05-03 14:16 -------
*** Bug 31697 has been marked as a duplicate of this bug. ***


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [4.3 Regression] -march=opteron -ftree-vectorize generates wrong code

[burnus at gcc dot gnu dot org]

------- Comment #9 from burnus at gcc dot gnu dot org  2007-05-03 14:18 -------
As the fix has been checked in and it works (at least here ;-), mark as FIXED.


-- 

burnus at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699

[Bug middle-end/31699] [4.3 Regression] -march=opteron -ftree-vectorize generates wrong code

[irar at gcc dot gnu dot org]

------- Comment #10 from irar at gcc dot gnu dot org  2007-06-08 06:31 -------
Subject: Bug 31699

Author: irar
Date: Fri Jun  8 06:31:39 2007
New Revision: 125560

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=125560
Log:
        Backport from mainline:

        2007-05-03  Dorit Nuzman  <dorit@il.ibm.com>

        PR tree-optimization/31699
        * tree-vect-analyze.c (vect_update_misalignment_for_peel): Remove wrong
        code.
        (vect_enhance_data_refs_alignment): Compute peel amount using
        TYPE_VECTOR_SUBPARTS instead of vf.
        * tree-vect-transform.c (vect_gen_niters_for_prolog_loop): Likewise.


Added:
    branches/autovect-branch/gcc/testsuite/gcc.dg/vect/pr31699.c
    branches/autovect-branch/gcc/testsuite/gcc.dg/vect/vect-multitypes-11.c
Modified:
    branches/autovect-branch/gcc/ChangeLog.autovect
    branches/autovect-branch/gcc/testsuite/ChangeLog.autovect
   
branches/autovect-branch/gcc/testsuite/gcc.dg/vect/vect-floatint-conversion-1.c
   
branches/autovect-branch/gcc/testsuite/gcc.dg/vect/vect-intfloat-conversion-1.c
    branches/autovect-branch/gcc/testsuite/gcc.dg/vect/vect-iv-4.c
    branches/autovect-branch/gcc/testsuite/gcc.dg/vect/vect-multitypes-1.c
    branches/autovect-branch/gcc/testsuite/gcc.dg/vect/vect-multitypes-4.c
    branches/autovect-branch/gcc/testsuite/lib/target-supports.exp
    branches/autovect-branch/gcc/tree-vect-analyze.c
    branches/autovect-branch/gcc/tree-vect-transform.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31699