re PR middle-end/38271 (Spurious / missing "... used uninitialized in this function" warning)

gcc/ChangeLog:
PR middle-end/38271
* tree-sra.c (sra_build_bf_assignment): Avoid warnings for
variables initialized from SRAed bit fields.
gcc/testsuite/ChangeLog:
PR middle-end/38271
* gcc.dg/torture/pr38271.c: New.

From-SVN: r142651

gcc/ChangeLog

+2008-12-10  Alexandre Oliva  <aoliva@redhat.com>
+
+	PR middle-end/38271
+	* tree-sra.c (sra_build_bf_assignment): Avoid warnings for
+	variables initialized from SRAed bit fields.
+
 2008-12-10  Martin Guy <martinwguy@yahoo.it>
 
 	PR target/37668

gcc/testsuite/ChangeLog

+2008-12-10  Alexandre Oliva  <aoliva@redhat.com>
+
+	PR middle-end/38271
+	* gcc.dg/torture/pr38271.c: New.
+
 2008-12-10  Ira Rosen  <irar@il.ibm.com>
 
 	PR tree-optimization/37416

gcc/testsuite/gcc.dg/torture/pr38271.c

+/* { dg-do compile } */
+/* { dg-options "-Wuninitialized" } */
+
+struct xxx {
+    short a;
+    short b;
+    void *c;
+};
+
+void bar(struct xxx);
+
+void foo(struct xxx *p, int i)
+{
+  struct xxx s0 = *p;
+  struct xxx s = s0;
+  if (s.a) i++;
+  bar(s);
+}

gcc/tree-sra.c

@@ -2354,14 +2354,17 @@ sra_build_bf_assignment (tree dst, tree src)
       tmp = var;
       if (!is_gimple_variable (tmp))
 	tmp = unshare_expr (var);
+      else
+	TREE_NO_WARNING (var) = true;
 
       tmp2 = make_rename_temp (utype, "SR");
 
       if (INTEGRAL_TYPE_P (TREE_TYPE (var)))
-	stmt = gimple_build_assign (tmp2, fold_convert (utype, tmp));
+	tmp = fold_convert (utype, tmp);
       else
-	stmt = gimple_build_assign (tmp2, fold_build1 (VIEW_CONVERT_EXPR,
-						       utype, tmp));
+	tmp = fold_build1 (VIEW_CONVERT_EXPR, utype, tmp);
+
+      stmt = gimple_build_assign (tmp2, tmp);
       gimple_seq_add_stmt (&seq, stmt);
     }
   else