[Bug tree-optimization/37574] New: [4.4 Regression] ICE with the vectorizer and GC

[Bug tree-optimization/37574] New: [4.4 Regression] ICE with the vectorizer and GC

[pinskia at gcc dot gnu dot org]

I noticed this while working on a rs6000 back-end patch and was questioning how
I could have caused this failure and then I noticed it was a GC issue and could
be reproduced without my patch.
Anyways here is the testcase reduced from vect-outer-4m.c:
unsigned short in[40 +128];
int main (void) {
  int i = 0, j = 0;
  unsigned int diff;
  unsigned int s=0,sum=0;
  for (i = 0; i < 40;i++)
  {
     diff = 0;
     for (j = 0; j < 128;j+=8) 
       diff += in[j+i];
     s += ((unsigned short)diff>>3);
   }
   if (s != sum)
     abort ();
 }
--- CUT ---
Compile with -O2 -ftree-vectorize  --param ggc-min-expand=0 --param
ggc-min-heapsize=0 -maltivec to reproduce the bug.


-- 
           Summary: [4.4 Regression] ICE with the vectorizer and GC
           Product: gcc
           Version: 4.4.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code, GC
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: pinskia at gcc dot gnu dot org
GCC target triplet: powerpc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574

[Bug tree-optimization/37574] [4.4 Regression] ICE with the vectorizer and GC

[pinskia at gcc dot gnu dot org]

-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.4.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574

[Bug tree-optimization/37574] [4.4 Regression] ICE with the vectorizer and GC

[jakub at gcc dot gnu dot org]

------- Comment #1 from jakub at gcc dot gnu dot org  2008-09-19 13:58 -------
The problem is const_vector_from_tree called on:
 <vector_cst 0x7ffff3375e10
    type <vector_type 0x7ffff33ed540 __vector signed int
        type <integer_type 0x7ffff332d540 int sizes-gimplified public SI
            size <integer_cst 0x7ffff3319930 constant 32>
            unit size <integer_cst 0x7ffff33195a0 constant 4>
            align 32 symtab 0 alias set -1 canonical type 0x7ffff332d540
precision 32 min <integer_cst 0x7ffff33198a0 -2147483648> max <integer_cst
0x7ffff33198d0 2147483647>
            pointer_to_this <pointer_type 0x7ffff333c9c0>>
        V4SI
        size <integer_cst 0x7ffff3319c90 constant 128>
        unit size <integer_cst 0x7ffff3319cc0 constant 16>
        align 128 symtab 0 alias set -1 canonical type 0x7ffff33ed540 nunits 4>
    constant
    elt0:  <integer_cst 0x7ffff3352570 type <integer_type 0x7ffff332d540 int>
constant 3> elt1:  <integer_cst 0x7ffff3352570 3> elt2:  <integer_cst
0x7ffff3352570 3> elt3:  <integer_cst 0x7ffff3352570 3> elt4:  <integer_cst
0x7ffff3352570 3> elt5:  <integer_cst 0x7ffff3352570 3> elt6:  <integer_cst
0x7ffff3352570 3> elt7:  <integer_cst 0x7ffff3352570 3>>

Note V4SImode, yet 8 elements.  This allocates a vector with rtvec_alloc (4),
yet fills in 8 elements.  Looking what creates it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574

[Bug tree-optimization/37574] [4.4 Regression] ICE with the vectorizer and GC

[jakub at gcc dot gnu dot org]

------- Comment #2 from jakub at gcc dot gnu dot org  2008-09-19 14:12 -------
vect_get_vec_def_for_operand has:
  tree vectype = STMT_VINFO_VECTYPE (stmt_vinfo);
  int nunits = TYPE_VECTOR_SUBPARTS (vectype);
...
    /* Case 1: operand is a constant.  */
    case vect_constant_def:
...
        for (i = nunits - 1; i >= 0; --i)
          {
            t = tree_cons (NULL_TREE, op, t);
          }
        vector_type = get_vectype_for_scalar_type (TREE_TYPE (op));
        gcc_assert (vector_type);
        vec_cst = build_vector (vector_type, t);
and similarly in a few other cases.  vectype in this case is V8HI, but op is
SImode, so nunits is 8, yet vector_type has just 4 units.


-- 

jakub at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |irar at gcc dot gnu dot org
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2008-09-19 14:12:43
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574

[Bug tree-optimization/37574] [4.4 Regression] ICE with the vectorizer and GC

[dorit at gcc dot gnu dot org]

-- 

dorit at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |dorit at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2008-09-19 14:12:43         |2008-09-21 13:17:55
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574

[Bug tree-optimization/37574] [4.4 Regression] ICE with the vectorizer and GC

[dorit at gcc dot gnu dot org]

------- Comment #3 from dorit at gcc dot gnu dot org  2008-09-21 13:18 -------
happens during outer-loop vectorization. I'm looking into it.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574

[Bug tree-optimization/37574] [4.4 Regression] ICE with the vectorizer and GC

[dorit at gcc dot gnu dot org]

------- Comment #4 from dorit at gcc dot gnu dot org  2008-09-26 06:29 -------
Subject: Bug 37574

Author: dorit
Date: Fri Sep 26 06:28:01 2008
New Revision: 140685

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=140685
Log:
        PR tree-optimization/37574
        * tree-vectorizer.c (vect_is_simple_use): Fix indentation.
        * tree-vect-transform.c (vect_get_constant_vectors): Use vectype
        instead of vector_type for constants. Take computation out of loop.
        (vect_get_vec_def_for_operand): Use only vectype for constant case,
        and use only vector_type for invariant case.
        (get_initial_def_for_reduction): Use vectype instead of vector_type.


Added:
    trunk/gcc/testsuite/gcc.dg/vect/ggc-pr37574.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/vect/vect.exp
    trunk/gcc/tree-vect-transform.c
    trunk/gcc/tree-vectorizer.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574

[Bug tree-optimization/37574] [4.4 Regression] ICE with the vectorizer and GC

[jakub at gcc dot gnu dot org]

------- Comment #5 from jakub at gcc dot gnu dot org  2008-09-29 22:46 -------
Fixed.


-- 

jakub at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37574