[PATCH] Fix PR56321

[Richard Biener]

This fixes PR56321 - the unlink_stmt_vdef was a no-op as it was
called after release_defs.  Oops.

Committed as obvoious.

Richard.

2013-02-18  Richard Biener  <rguent...@suse.de>

        PR tree-optimization/56321
        * tree-ssa-reassoc.c (propagate_op_to_single_use): Properly
        order SSA name release and virtual operand unlinking.

        * gcc.dg/torture/pr56321.c: New testcase.

Index: gcc/tree-ssa-reassoc.c
===================================================================
*** gcc/tree-ssa-reassoc.c      (revision 196115)
--- gcc/tree-ssa-reassoc.c      (working copy)
*************** propagate_op_to_single_use (tree op, gim
*** 1062,1072 ****
    if (TREE_CODE (op) != SSA_NAME)
      update_stmt (use_stmt);
    gsi = gsi_for_stmt (stmt);
    gsi_remove (&gsi, true);
    release_defs (stmt);
- 
-   if (is_gimple_call (stmt))
-     unlink_stmt_vdef (stmt);
  }
  
  /* Walks the linear chain with result *DEF searching for an operation
--- 1062,1070 ----
    if (TREE_CODE (op) != SSA_NAME)
      update_stmt (use_stmt);
    gsi = gsi_for_stmt (stmt);
+   unlink_stmt_vdef (stmt);
    gsi_remove (&gsi, true);
    release_defs (stmt);
  }
  
  /* Walks the linear chain with result *DEF searching for an operation
Index: gcc/testsuite/gcc.dg/torture/pr56321.c
===================================================================
*** gcc/testsuite/gcc.dg/torture/pr56321.c      (revision 0)
--- gcc/testsuite/gcc.dg/torture/pr56321.c      (working copy)
***************
*** 0 ****
--- 1,11 ----
+ /* { dg-do compile } */
+ /* { dg-options "-ffast-math" } */
+ 
+ void foo(int n, int nreps, float tdgefa, float tdgesl)
+ {
+   float kflops,ops;
+   ops=((2.0*n*n*n)/3.0+2.0*n*n);
+   kflops=2.*nreps*ops/(1000.*(tdgefa+tdgesl));
+ 
+   __builtin_printf ("%f\n", kflops);
+ }