[Bug tree-optimization/55110] [4.8 Regression] Internal compiler error in vectorizable_reduction, at tree-vect-loop.c:4633

[jakub at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=55110



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



           What    |Removed                     |Added

----------------------------------------------------------------------------

                 CC|                            |jakub at gcc dot gnu.org



--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-11-26 
10:35:44 UTC ---

I'd say either we should nuke the bogus

  gcc_assert (STMT_VINFO_RELATED_STMT (orig_stmt_info) == stmt);

assertion, which predates the introduction of

STMT_VINFO_PATTERN_DEF_STMT (and later STMT_VINFO_PATTERN_DEF_SEQ) - both in

4.7 cycle, or just return false; if it isn't equal.

We won't successfully vectorize this anyway, orig_code is still TRUNC_DIV_EXPR

and that is not a handled reduction (and even if we'd handled it as the signed

MULT_HIGHPART_EXPR reduction, that isn't handled either).



So, I'd propose this (if we wanted to assert something, it would need to

walk the STMT_VINFO_PATTERN_DEF_SEQ sequence and checking whether stmt isn't in

there too):



2012-11-26  Jakub Jelinek  <ja...@redhat.com>



    PR tree-optimization/55110

    * tree-vect-loop.c (vectorizable_reduction): Don't assert

    that STMT_VINFO_RELATED_STMT of orig_stmt is stmt.



    * gcc.dg/pr55110.c: New test.



--- gcc/tree-vect-loop.c.jj    2012-11-21 16:00:12.000000000 +0100

+++ gcc/tree-vect-loop.c    2012-11-26 11:24:42.903995009 +0100

@@ -4624,7 +4624,6 @@ vectorizable_reduction (gimple stmt, gim

   if (orig_stmt)

     {

       orig_stmt_info = vinfo_for_stmt (orig_stmt);

-      gcc_assert (STMT_VINFO_RELATED_STMT (orig_stmt_info) == stmt);

       gcc_assert (STMT_VINFO_IN_PATTERN_P (orig_stmt_info));

       gcc_assert (!STMT_VINFO_IN_PATTERN_P (stmt_info));

     }

--- gcc/testsuite/gcc.dg/pr55110.c.jj    2012-11-26 11:31:32.008587313 +0100

+++ gcc/testsuite/gcc.dg/pr55110.c    2012-11-26 11:31:09.000000000 +0100

@@ -0,0 +1,13 @@

+/* PR tree-optimization/55110 */

+/* { dg-do compile } */

+/* { dg-options "-O1 -ftree-vectorize" } */

+

+int

+foo (int x)

+{

+  int a, b;

+  for (b = 0; b < 8; b++)

+    for (a = 0; a < 2; a++)

+      x /= 3;

+  return x;

+}