[Bug tree-optimization/71261] [7 Regression] Trunk GCC hangs on knl and broadwell targets

[rguenth at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71261

--- Comment #10 from Richard Biener <rguenth at gcc dot gnu.org> ---
For reference (untested):

Index: tree-if-conv.c
===================================================================
--- tree-if-conv.c      (revision 236695)
+++ tree-if-conv.c      (working copy)
@@ -2529,7 +2529,7 @@ ifcvt_split_def_stmt (gimple *def_stmt,
   gimple *copy_stmt;
   gimple_stmt_iterator gsi;
   use_operand_p use_p;
-  imm_use_iterator imm_iter;
+  ssa_op_iter imm_iter;

   var = gimple_assign_lhs (def_stmt);
   copy_stmt = gimple_copy (def_stmt);
@@ -2548,9 +2548,9 @@ ifcvt_split_def_stmt (gimple *def_stmt,
       print_generic_expr (dump_file, lhs, TDF_SLIM);
       fprintf (dump_file, "\n");
     }
-  FOR_EACH_IMM_USE_FAST (use_p, imm_iter, var)
+  FOR_EACH_SSA_USE_OPERAND (use_p, use_stmt, imm_iter, SSA_OP_USE)
     {
-      if (USE_STMT (use_p) != use_stmt)
+      if (USE_FROM_PTR (use_p) != var)
        continue;
       SET_USE (use_p, lhs);
       break;