re PR tree-optimization/88069 (ICE in check_loop_closed_ssa_def, at tree-ssa-loop...

2018-11-20  Jeff Law  <law@redhat.com>

	PR tree-optimization/88069
	* tree-ssa-dom.c (record_equivalences_from_phis): Propagate away
	degenerate virtual PHIs.

From-SVN: r266343

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 692f3fb1961576316fd558a15bd49b56d32e0190..967967641f38208fc26e7cf853990064d58e4774 100644 (file)
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,9 @@
+2018-11-20  Jeff Law  <law@redhat.com>
+
+       PR tree-optimization/88069
+       * tree-ssa-dom.c (record_equivalences_from_phis): Propagate away
+       degenerate virtual PHIs.
+
 2018-11-21  H.J. Lu  <hongjiu.lu@intel.com>
 
        PR target/87317

diff --git a/gcc/tree-ssa-dom.c b/gcc/tree-ssa-dom.c
index 7787da8b237bf829f27163b8b207638e01feae59..ce840488403bd0bc9b18d4dca36bc45251161ad5 100644 (file)
--- a/gcc/tree-ssa-dom.c
+++ b/gcc/tree-ssa-dom.c
@@ -1106,10 +1106,13 @@ record_equivalences_from_phis (basic_block bb)
 {
   gphi_iterator gsi;
 
-  for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); gsi_next (&gsi))
+  for (gsi = gsi_start_phis (bb); !gsi_end_p (gsi); )
     {
       gphi *phi = gsi.phi ();
 
+      /* We might eliminate the PHI, so advance GSI now.  */
+      gsi_next (&gsi);
+
       tree lhs = gimple_phi_result (phi);
       tree rhs = NULL;
       size_t i;
@@ -1159,9 +1162,26 @@ record_equivalences_from_phis (basic_block bb)
         this, since this is a true assignment and not an equivalence
         inferred from a comparison.  All uses of this ssa name are dominated
         by this assignment, so unwinding just costs time and space.  */
-      if (i == gimple_phi_num_args (phi)
-         && may_propagate_copy (lhs, rhs))
-       set_ssa_name_value (lhs, rhs);
+      if (i == gimple_phi_num_args (phi))
+       {
+         if (may_propagate_copy (lhs, rhs))
+           set_ssa_name_value (lhs, rhs);
+         else if (virtual_operand_p (lhs))
+           {
+             gimple *use_stmt;
+             imm_use_iterator iter;
+             use_operand_p use_p;
+             /* For virtual operands we have to propagate into all uses as
+                otherwise we will create overlapping life-ranges.  */
+             FOR_EACH_IMM_USE_STMT (use_stmt, iter, lhs)
+               FOR_EACH_IMM_USE_ON_STMT (use_p, iter)
+                 SET_USE (use_p, rhs);
+             if (SSA_NAME_OCCURS_IN_ABNORMAL_PHI (lhs))
+               SSA_NAME_OCCURS_IN_ABNORMAL_PHI (rhs) = 1;
+             gimple_stmt_iterator tmp_gsi = gsi_for_stmt (phi);
+             remove_phi_node (&tmp_gsi, true);
+           }
+       }
     }
 }