re PR c++/38908 (Unexplained "'<anonymous>' is used uninitialized in this…

re PR c++/38908 (Unexplained "'<anonymous>' is used uninitialized in this function" warning in cc1plus -m64)

2009-01-28  Richard Guenther  <rguenther@suse.de>

	PR middle-end/38908
	* tree-ssa.c (warn_uninitialized_var): Do not warn for seemingly
	uninitialized aggregate uses in call arguments.

	* g++.dg/warn/Wuninitialized-2.C: New testcase.

From-SVN: r143722

gcc/ChangeLog

+2009-01-28  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/38908
+	* tree-ssa.c (warn_uninitialized_var): Do not warn for seemingly
+	uninitialized aggregate uses in call arguments.
+
 2009-01-28  Paolo Bonzini  <bonzini@gnu.org>
 
 	PR tree-optimization/38984

gcc/testsuite/ChangeLog

+2009-01-28  Richard Guenther  <rguenther@suse.de>
+
+	PR middle-end/38908
+	* g++.dg/warn/Wuninitialized-2.C: New testcase.
+
 2009-01-28  Paolo Bonzini  <bonzini@gnu.org>
 
 	PR tree-optimization/38984

gcc/testsuite/g++.dg/warn/Wuninitialized-2.C

+/* { dg-do compile } */
+/* { dg-options "-O -Wuninitialized" } */
+
+struct S8 { template<typename T> S8(T) { } };
+
+template<typename T> struct S10;
+template<typename T> struct S10<T()> { typedef T S12; typedef S8 S1(); };
+
+template<typename T> struct S3 { };
+template<typename T> struct S11 { S11(S3<T>); };
+
+struct S2
+{
+  template<typename T> operator S11<T>() { return S11<T>(S5<T>()); }
+  template<typename T> struct S5:public S3<T>
+  {
+    virtual typename S10<T>::S12 S13() {
+      return 0;
+    }
+  };
+};
+
+template<typename T> S11<T> S6(S3<T>) { return S11<T>(S3<T>()); }
+template<typename S12> struct S7 { typedef S12 S15(); };
+
+struct S4
+{
+  template<typename T> operator S11<T>()
+  {
+    struct S14:public S3<T>
+    { 
+      S14(S2 x):S11_(x) { }
+      S11<typename S7<typename S10<T>::S12>::S15> S11_;
+    };
+    return S6(S14(S11_));
+  }
+  S2 S11_;
+};
+
+struct S9
+{
+  template<typename F> operator S11<F>() { return S11<F>(S14<F>(S11_)); }
+  template<typename F> struct S14:public S3<F>
+  {
+    S14(S4 x):S11_(x) { }
+    S11<typename S10<F>::S1> S11_;
+  };
+  S4 S11_;
+};
+
+void S15(S11<void()>);
+void S16() { S9 x; S15(x); }
+

gcc/tree-ssa.c

@@ -1496,9 +1496,13 @@ warn_uninitialized_var (tree *tp, int *walk_subtrees, void *data_)
             || !gimple_aliases_computed_p (cfun))
 	  return NULL_TREE;
 
+	/* If the load happens as part of a call do not warn about it.  */
+	if (is_gimple_call (data->stmt))
+	  return NULL_TREE;
+
 	vuse = SINGLE_SSA_USE_OPERAND (data->stmt, SSA_OP_VUSE);
 	if (vuse == NULL_USE_OPERAND_P)
-	    return NULL_TREE;
+	  return NULL_TREE;
 
 	op = USE_FROM_PTR (vuse);
 	if (t != SSA_NAME_VAR (op)