[Bug target/52607] v4df __builtin_shuffle with {0,2,1,3} or {1,3,0,2}

["rth at gcc dot gnu.org" <gcc-bugzilla at gcc dot gnu dot org>]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=52607

Richard Henderson <rth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|2012-03-20 00:00:00         |2012-03-29
     Ever Confirmed|0                           |1

--- Comment #23 from Richard Henderson <rth at gcc dot gnu.org> 2012-03-29 13:36:23 UTC ---
(In reply to comment #18)

+  if (!d->testing_p)
+    dsecond.target = gen_reg_rtx (dsecond.vmode);
+  dfirst.op1 = dsecond.target;

This bit has a problem with testing_p in that we'll have op0==op1
while testing and not when expanding.  Which means that testing_p
will be checking something else.

I've been meaning to convert i386 from op0==op1 to one_operand_p,
like I used in targets I converted later, like ia64.  I'll see about
making this change this afternoon, and then you can update your
patch to match.

+  ok = expand_vec_perm_1 (&dsecond);
+  ok &= ix86_expand_vec_perm_const_1 (&dfirst);
+
+  if (!ok)
+    return false;
+
+  return true;

Better with a short-circuit to avoid extra work:

  return (expand_vec_perm_1 (&dsecond)
          && ix86_expand_vec_perm_const_1 (&dfirst));

Otherwise the patch looks pretty good.