Don't create superfluous parm in expand_omp_taskreg

2015-08-23  Tom de Vries  <tom@codesourcery.com>

	* omp-low.c (expand_omp_taskreg): If in ssa, set rhs of parcopy stmt to
	parm_decl, rather than generating a dummy default def in cfun.
	* tree-cfg.c (replace_ssa_name): Assume no default defs.  Make sure
	ssa_name from cfun and child_fn do not share a stmt as def stmt.
	(move_stmt_op): Handle PARM_DECl.
	(gather_ssa_name_hash_map_from): New function.
	(move_sese_region_to_fn): Add default defs for function params, and add
	them to vars_map.  Release copied ssa names.
	* tree-cfg.h (gather_ssa_name_hash_map_from): Declare.

From-SVN: r227103

1 files changed, 10 insertions, 10 deletions

diff --git a/gcc/omp-low.c b/gcc/omp-low.c
index 7cf51b3..d181101 100644
--- a/gcc/omp-low.c
+++ b/gcc/omp-low.c
@@ -5417,7 +5417,7 @@ expand_omp_taskreg (struct omp_region *region)
 	  basic_block entry_succ_bb
 	    = single_succ_p (entry_bb) ? single_succ (entry_bb)
 				       : FALLTHRU_EDGE (entry_bb)->dest;
-	  tree arg, narg;
+	  tree arg;
 	  gimple parcopy_stmt = NULL;
 
 	  for (gsi = gsi_start_bb (entry_succ_bb); ; gsi_next (&gsi))
@@ -5462,15 +5462,15 @@ expand_omp_taskreg (struct omp_region *region)
 	    }
 	  else
 	    {
-	      /* If we are in ssa form, we must load the value from the default
-		 definition of the argument.  That should not be defined now,
-		 since the argument is not used uninitialized.  */
-	      gcc_assert (ssa_default_def (cfun, arg) == NULL);
-	      narg = make_ssa_name (arg, gimple_build_nop ());
-	      set_ssa_default_def (cfun, arg, narg);
-	      /* ?? Is setting the subcode really necessary ??  */
-	      gimple_omp_set_subcode (parcopy_stmt, TREE_CODE (narg));
-	      gimple_assign_set_rhs1 (parcopy_stmt, narg);
+	      tree lhs = gimple_assign_lhs (parcopy_stmt);
+	      gcc_assert (SSA_NAME_VAR (lhs) == arg);
+	      /* We'd like to set the rhs to the default def in the child_fn,
+		 but it's too early to create ssa names in the child_fn.
+		 Instead, we set the rhs to the parm.  In
+		 move_sese_region_to_fn, we introduce a default def for the
+		 parm, map the parm to it's default def, and once we encounter
+		 this stmt, replace the parm with the default def.  */
+	      gimple_assign_set_rhs1 (parcopy_stmt, arg);
 	      update_stmt (parcopy_stmt);
 	    }
 	}