[Bug tree-optimization/37102] [4.3/4.4 Regression] out-of-SSA is broken

[rguenth at gcc dot gnu dot org]

------- Comment #12 from rguenth at gcc dot gnu dot org  2008-09-17 14:25 -------
Ok, so I think we should be fine if we ignore PHI nodes with zero-use results
during building the elimination graph - chained unused PHIs will have lifeness
computed for all but the PHI node with the zero-use result.

So, on the 4.3 branch the following fixes the failure for me:

Index: tree-outof-ssa.c
===================================================================
*** tree-outof-ssa.c    (revision 140417)
--- tree-outof-ssa.c    (working copy)
*************** eliminate_build (elim_graph g, basic_blo
*** 321,326 ****
--- 321,329 ----

    for (phi = phi_nodes (B); phi; phi = PHI_CHAIN (phi))
      {
+       if (has_zero_uses (PHI_RESULT (phi)))
+       continue;
+ 
        T0 = var_to_partition_to_var (g->map, PHI_RESULT (phi));

        /* Ignore results which are not in partitions.  */


I am now giving this testing.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=37102