re PR middle-end/44133 (Uninit warning regression with new SRA)

2010-05-17  Martin Jambor  <mjambor@suse.cz>

	PR middle-end/44133
	* tree-sra.c (create_access_replacement): New parameter rename, mark
	the replaement for renaming only when it is true.
	(get_access_replacement): Pass true in the rename parameter of
	create_access_replacement.
	(get_unrenamed_access_replacement): New function.
	(replace_uses_with_default_def_ssa_name): New parameter racc, get the
	replacement declaration from it.

	* testsuite/gcc.dg/tree-ssa/pr44133.c: New test.
	* testsuite/gcc.dg/tree-ssa/sra-9.c: Make the scan regular
	expression more precise.

From-SVN: r159482

gcc/ChangeLog

+2010-05-17  Martin Jambor  <mjambor@suse.cz>
+
+	PR middle-end/44133
+	* tree-sra.c (create_access_replacement): New parameter rename, mark
+	the replaement for renaming only when it is true.
+	(get_access_replacement): Pass true in the rename parameter of
+	create_access_replacement.
+	(get_unrenamed_access_replacement): New function.
+	(replace_uses_with_default_def_ssa_name): New parameter racc, get the
+	replacement declaration from it.
+
 2010-05-17  Bernd Schmidt  <bernds@codesourcery.com>
 
 	* function.c (try_fit_stack_local, add_frame_space): New static

gcc/testsuite/ChangeLog

+2010-05-17  Martin Jambor  <mjambor@suse.cz>
+
+	PR middle-end/44133
+	* gcc.dg/tree-ssa/pr44133.c: New test.
+	* gcc.dg/tree-ssa/sra-9.c: Make the scan regular expression more
+	precise.
+
 2010-05-17  Janus Weil  <janus@gcc.gnu.org>
 
 	PR fortran/44044

gcc/testsuite/gcc.dg/tree-ssa/pr44133.c

+/* { dg-do compile } */
+/* { dg-options "-O2 -Wall" } */
+
+struct S { int i, j; };
+
+int foo (int l)
+{
+  struct S s;
+  s.j = l - 22;   /* { dg-warning ".s\.i. is used uninitialized" } */
+  return s.i + s.j;
+}

gcc/testsuite/gcc.dg/tree-ssa/sra-9.c

@@ -16,5 +16,5 @@ int foo (int d)
 }
 
 /* There should be no reference to s.b.  */
-/* { dg-final { scan-tree-dump-times "s\.b" 0 "optimized"} } */
+/* { dg-final { scan-tree-dump-times "= s\.b" 0 "optimized"} } */
 /* { dg-final { cleanup-tree-dump "optimized" } } */

gcc/tree-sra.c

@@ -1586,14 +1586,15 @@ sort_and_splice_var_accesses (tree var)
    ACCESS->replacement.  */
 
 static tree
-create_access_replacement (struct access *access)
+create_access_replacement (struct access *access, bool rename)
 {
   tree repl;
 
   repl = create_tmp_var (access->type, "SR");
   get_var_ann (repl);
   add_referenced_var (repl);
-  mark_sym_for_renaming (repl);
+  if (rename)
+    mark_sym_for_renaming (repl);
 
   if (!access->grp_partial_lhs
       && (TREE_CODE (access->type) == COMPLEX_TYPE
@@ -1669,10 +1670,24 @@ get_access_replacement (struct access *access)
   gcc_assert (access->grp_to_be_replaced);
 
   if (!access->replacement_decl)
-    access->replacement_decl = create_access_replacement (access);
+    access->replacement_decl = create_access_replacement (access, true);
   return access->replacement_decl;
 }
 
+/* Return ACCESS scalar replacement, create it if it does not exist yet but do
+   not mark it for renaming.  */
+
+static inline tree
+get_unrenamed_access_replacement (struct access *access)
+{
+  gcc_assert (!access->grp_to_be_replaced);
+
+  if (!access->replacement_decl)
+    access->replacement_decl = create_access_replacement (access, false);
+  return access->replacement_decl;
+}
+
+
 /* Build a subtree of accesses rooted in *ACCESS, and move the pointer in the
    linked list along the way.  Stop when *ACCESS is NULL or the access pointed
    to it is not "within" the root.  */
@@ -2507,29 +2522,21 @@ sra_modify_constructor_assign (gimple *stmt, gimple_stmt_iterator *gsi)
 }
 
 /* Create a new suitable default definition SSA_NAME and replace all uses of
-   SSA with it.  */
+   SSA with it, RACC is access describing the uninitialized part of an
+   aggregate that is being loaded.  */
 
 static void
-replace_uses_with_default_def_ssa_name (tree ssa)
+replace_uses_with_default_def_ssa_name (tree ssa, struct access *racc)
 {
-  tree repl, decl = SSA_NAME_VAR (ssa);
-  if (TREE_CODE (decl) == PARM_DECL)
-    {
-      tree tmp = create_tmp_reg (TREE_TYPE (decl), "SR");
+  tree repl, decl;
 
-      get_var_ann (tmp);
-      add_referenced_var (tmp);
-      repl = make_ssa_name (tmp, gimple_build_nop ());
-      set_default_def (tmp, repl);
-    }
-  else
+  decl = get_unrenamed_access_replacement (racc);
+
+  repl = gimple_default_def (cfun, decl);
+  if (!repl)
     {
-      repl = gimple_default_def (cfun, decl);
-      if (!repl)
-	{
-	  repl = make_ssa_name (decl, gimple_build_nop ());
-	  set_default_def (decl, repl);
-	}
+      repl = make_ssa_name (decl, gimple_build_nop ());
+      set_default_def (decl, repl);
     }
 
   replace_uses_by (ssa, repl);
@@ -2717,7 +2724,7 @@ sra_modify_assign (gimple *stmt, gimple_stmt_iterator *gsi)
 					     false, false);
 		  gcc_assert (*stmt == gsi_stmt (*gsi));
 		  if (TREE_CODE (lhs) == SSA_NAME)
-		    replace_uses_with_default_def_ssa_name (lhs);
+		    replace_uses_with_default_def_ssa_name (lhs, racc);
 
 		  unlink_stmt_vdef (*stmt);
 		  gsi_remove (gsi, true);