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[Bug tree-optimization/51074] No constant folding performed for VEC_PERM_EXPR, VEC_INTERLEAVE*EXPR, VEC_EXTRACT*EXPR


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=51074

--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2011-11-10 13:47:47 UTC ---
Created attachment 25784
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25784
gcc47-pr51074.patch

Folding patch.  For __builtin_shuffle it works well.

For the interleaved stores of addresses like:
char *a[1024];
extern char b[];

void
foo ()
{
  int i;
  for (i = 0; i < 1024; i += 16)
    {
      a[i] = b + 1;
      a[i + 15] = b + 2;
      a[i + 1] = b + 3;
      a[i + 14] = b + 4;
      a[i + 2] = b + 5;
      a[i + 13] = b + 6;
      a[i + 3] = b + 7;
      a[i + 12] = b + 8;
      a[i + 4] = b + 9;
      a[i + 11] = b + 10;
      a[i + 5] = b + 11;
      a[i + 10] = b + 12;
      a[i + 6] = b + 13;
      a[i + 9] = b + 14;
      a[i + 7] = b + 15;
      a[i + 8] = b + 16;
    }
}

it doesn't help, I'd need to do something like:
--- tree-ssa-propagate.c.jj 2011-09-29 14:25:46.000000000 +0200
+++ tree-ssa-propagate.c 2011-11-10 14:33:55.923268422 +0100
@@ -610,6 +610,8 @@ valid_gimple_rhs_p (tree expr)
       return false;

     case tcc_exceptional:
+      if (code == CONSTRUCTOR && TREE_CODE (TREE_TYPE (expr)) == VECTOR_TYPE)
+        break;
       if (code != SSA_NAME)
         return false;
       break;

but that isn't helpful either (because it puts the vector CONSTRUCTOR inside of
loop and thus prevents vectorization - is expanded piecewise).


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