[Bug tree-optimization/51799] New: Compiler ICE in vect_is_simple_use_1

[Bug tree-optimization/51799] New: Compiler ICE in vect_is_simple_use_1

[mgretton at sourceware dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

             Bug #: 51799
           Summary: Compiler ICE in vect_is_simple_use_1
    Classification: Unclassified
           Product: gcc
           Version: 4.7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: tree-optimization
        AssignedTo: unassigned@gcc.gnu.org
        ReportedBy: mgretton@sourceware.org
            Target: arm-*-*


Created attachment 26281
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=26281
Failing test case.

The attached test case causes the compiler to ICE as follows:

$ arm-none-eabi-gcc  -O1 -ftree-vectorize -mcpu=cortex-a9 \
      -mfpu=neon -mfloat-abi=softfp ice.c 
ice.c: In function 'f0a':
ice.c:7:1: internal compiler error: in vect_is_simple_use_1, at
tree-vect-stmts.c:5987
Please submit a full bug report,
with preprocessed source if appropriate.
See <http://gcc.gnu.org/bugs.html> for instructions.

Checked against trunk revision 183018.

[Bug tree-optimization/51799] Compiler ICE in vect_is_simple_use_1

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |irar at gcc dot gnu.org

--- Comment #1 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-10 10:07:13 UTC ---
Did it work with 4.6.x?  If so, please mark it as regression.

[Bug tree-optimization/51799] [4.7 Regression] Compiler ICE in vect_is_simple_use_1

[mgretton at sourceware dot org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

Matthew Gretton-Dann <mgretton at sourceware dot org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to work|                            |4.6.2
            Summary|Compiler ICE in             |[4.7 Regression] Compiler
                   |vect_is_simple_use_1        |ICE in vect_is_simple_use_1
      Known to fail|                            |4.7.0

--- Comment #2 from Matthew Gretton-Dann <mgretton at sourceware dot org> 2012-01-10 13:27:39 UTC ---
Doesn't ICE with GCC 4.6.2.

[Bug tree-optimization/51799] [4.7 Regression] Compiler ICE in vect_is_simple_use_1

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

Richard Guenther <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |4.7.0

--- Comment #3 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-01-10 14:03:21 UTC ---
Thanks for checking.

[Bug tree-optimization/51799] [4.7 Regression] Compiler ICE in vect_is_simple_use_1

[ramana at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

Ramana Radhakrishnan <ramana at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ice-on-valid-code
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-01-11
                 CC|                            |ramana at gcc dot gnu.org
     Ever Confirmed|0                           |1

[Bug tree-optimization/51799] [4.7 Regression] Compiler ICE in vect_is_simple_use_1

[irar at il dot ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

Ira Rosen <irar at il dot ibm.com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |ASSIGNED
                 CC|                            |irar at il dot ibm.com
         AssignedTo|unassigned at gcc dot       |irar at gcc dot gnu.org
                   |gnu.org                     |

--- Comment #4 from Ira Rosen <irar at il dot ibm.com> 2012-01-12 10:48:11 UTC ---
This is actually the same problem as in pr 51301, and the fix of 51301 looks
incomplete: we want an over-promoted sequence to end with type demotion
operation, so we need to check that properly:

Index: tree-vect-patterns.c
===================================================================
--- tree-vect-patterns.c        (revision 182840)
+++ tree-vect-patterns.c        (working copy)
@@ -1186,13 +1186,15 @@
     {
       use_lhs = gimple_assign_lhs (use_stmt);
       use_type = TREE_TYPE (use_lhs);
-      /* Support only type promotion or signedess change.  Check that USE_TYPE
-        is not bigger than the original type.  */
+      /* Support only type demotion or signedess change.  */
       if (!INTEGRAL_TYPE_P (use_type)
-          || TYPE_PRECISION (new_type) > TYPE_PRECISION (use_type)
-         || TYPE_PRECISION (type) < TYPE_PRECISION (use_type))
+         || TYPE_PRECISION (type) <= TYPE_PRECISION (use_type))
         return NULL;

+      /* Check that NEW_TYPE is not bigger than the conversion result.  */
+      if (TYPE_PRECISION (new_type) > TYPE_PRECISION (use_type))
+       return NULL;
+
       if (TYPE_UNSIGNED (new_type) != TYPE_UNSIGNED (use_type)
           || TYPE_PRECISION (new_type) != TYPE_PRECISION (use_type))
         {

I am going to test this patch.

[Bug tree-optimization/51799] [4.7 Regression] Compiler ICE in vect_is_simple_use_1

[irar at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

--- Comment #5 from irar at gcc dot gnu.org 2012-01-12 14:41:51 UTC ---
Author: irar
Date: Thu Jan 12 14:41:44 2012
New Revision: 183126

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=183126
Log:

        PR tree-optimization/51799
        * tree-vect-patterns.c (vect_recog_over_widening_pattern): Check
        that the last operation is a type demotion.


Added:
    trunk/gcc/testsuite/gcc.dg/vect/pr51799.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/testsuite/ChangeLog
    trunk/gcc/testsuite/gcc.dg/vect/vect-widen-shift-u8.c
    trunk/gcc/tree-vect-patterns.c

[Bug tree-optimization/51799] [4.7 Regression] Compiler ICE in vect_is_simple_use_1

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51799

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
                 CC|                            |jakub at gcc dot gnu.org
         Resolution|                            |FIXED

--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-01-12 16:49:21 UTC ---
Fixed.