re PR c/24010 (Duplicate C99 dot initializer warning missing)

	PR c/24010
	* c.opt (Woverride-init): New.
	* c-opts.c (c_common_post_options): Default warn_override_init to
	extra_warnings.
	* c-typeck.c (add_pending_init, output_init_element): Warn for
	overriding initializers without side effects.
	* doc/invoke.texi (-Woverride-init): Document.
	(-Wextra): Update.

testsuite:
	* gcc.dg/Woverride-init-1.c, gcc.dg/Woverride-init-2.c,
	gcc.dg/Woverride-init-3.c: New tests.

From-SVN: r117334

9 files changed, 134 insertions, 2 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index 7a0e026..e7fc16f 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,14 @@
+2006-09-30  Joseph S. Myers  <joseph@codesourcery.com>
+
+	PR c/24010
+	* c.opt (Woverride-init): New.
+	* c-opts.c (c_common_post_options): Default warn_override_init to
+	extra_warnings.
+	* c-typeck.c (add_pending_init, output_init_element): Warn for
+	overriding initializers without side effects.
+	* doc/invoke.texi (-Woverride-init): Document.
+	(-Wextra): Update.
+
 2006-09-30  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	PR rtl-optimization/28096
diff --git a/gcc/c-opts.c b/gcc/c-opts.c
index 5821dea..b74ce77 100644
--- a/gcc/c-opts.c
+++ b/gcc/c-opts.c
@@ -1016,12 +1016,14 @@ c_common_post_options (const char **pfilename)
   if (flag_objc_exceptions && !flag_objc_sjlj_exceptions)
     flag_exceptions = 1;
 
-  /* -Wextra implies -Wsign-compare and -Wmissing-field-initializers,
-     but not if explicitly overridden.  */
+  /* -Wextra implies -Wsign-compare, -Wmissing-field-initializers and
+     -Woverride-init, but not if explicitly overridden.  */
   if (warn_sign_compare == -1)
     warn_sign_compare = extra_warnings;
   if (warn_missing_field_initializers == -1)
     warn_missing_field_initializers = extra_warnings;
+  if (warn_override_init == -1)
+    warn_override_init = extra_warnings;
 
   /* -Wpointer_sign is disabled by default, but it is enabled if any
      of -Wall or -pedantic are given.  */
diff --git a/gcc/c-typeck.c b/gcc/c-typeck.c
index 00537ac..89bfed1 100644
--- a/gcc/c-typeck.c
+++ b/gcc/c-typeck.c
@@ -5737,6 +5737,8 @@ add_pending_init (tree purpose, tree value)
 	    {
 	      if (TREE_SIDE_EFFECTS (p->value))
 		warning_init ("initialized field with side-effects overwritten");
+	      else if (warn_override_init)
+		warning_init ("initialized field overwritten");
 	      p->value = value;
 	      return;
 	    }
@@ -5758,6 +5760,8 @@ add_pending_init (tree purpose, tree value)
 	    {
 	      if (TREE_SIDE_EFFECTS (p->value))
 		warning_init ("initialized field with side-effects overwritten");
+	      else if (warn_override_init)
+		warning_init ("initialized field overwritten");
 	      p->value = value;
 	      return;
 	    }
@@ -6230,6 +6234,8 @@ output_init_element (tree value, bool strict_string, tree type, tree field,
       if (TREE_SIDE_EFFECTS (VEC_last (constructor_elt,
 				       constructor_elements)->value))
 	warning_init ("initialized field with side-effects overwritten");
+      else if (warn_override_init)
+	warning_init ("initialized field overwritten");
 
       /* We can have just one union field set.  */
       constructor_elements = 0;
diff --git a/gcc/c.opt b/gcc/c.opt
index 12510d9..0aa0a3a 100644
--- a/gcc/c.opt
+++ b/gcc/c.opt
@@ -319,6 +319,10 @@ Woverloaded-virtual
 C++ ObjC++ Var(warn_overloaded_virtual)
 Warn about overloaded virtual function names
 
+Woverride-init
+C ObjC Var(warn_override_init) Init(-1)
+Warn about overriding initializers without side effects
+
 Wparentheses
 C ObjC C++ ObjC++ Var(warn_parentheses)
 Warn about possibly missing parentheses
diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
index d5a3b6b..6d7bc1e 100644
--- a/gcc/doc/invoke.texi
+++ b/gcc/doc/invoke.texi
@@ -2876,6 +2876,12 @@ This warning can be independently controlled by
 @option{-Wmissing-field-initializers}.
 
 @item
+An initialized field without side effects is overridden when using
+designated initializers (@pxref{Designated Inits, , Designated
+Initializers}).  This warning can be independently controlled by
+@option{-Woverride-init}.
+
+@item
 A function parameter is declared without a type specifier in K&R-style
 functions:
 
@@ -3302,6 +3308,18 @@ attribute.
 @opindex Wno-overflow
 Do not warn about compile-time overflow in constant expressions.
 
+@item -Woverride-init
+@opindex Woverride-init
+@opindex W
+@opindex Wextra
+Warn if an initialized field without side effects is overridden when
+using designated initializers (@pxref{Designated Inits, , Designated
+Initializers}).
+
+This warning is included in @option{-Wextra}.  To get other
+@option{-Wextra} warnings without this one, use @samp{-Wextra
+-Wno-override-init}.
+
 @item -Wpacked
 @opindex Wpacked
 Warn if a structure is given the packed attribute, but the packed
diff --git a/gcc/testsuite/ChangeLog b/gcc/testsuite/ChangeLog
index c5c774a..51599a7 100644
--- a/gcc/testsuite/ChangeLog
+++ b/gcc/testsuite/ChangeLog
@@ -1,3 +1,9 @@
+2006-09-30  Joseph S. Myers  <joseph@codesourcery.com>
+
+	PR c/24010
+	* gcc.dg/Woverride-init-1.c, gcc.dg/Woverride-init-2.c,
+	gcc.dg/Woverride-init-3.c: New tests.
+
 2006-09-30  Eric Botcazou  <ebotcazou@libertysurf.fr>
 
 	* gcc.c-torture/execute/20060930-1.c: New test.
diff --git a/gcc/testsuite/gcc.dg/Woverride-init-1.c b/gcc/testsuite/gcc.dg/Woverride-init-1.c
new file mode 100644
index 0000000..29eca30
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Woverride-init-1.c
@@ -0,0 +1,28 @@
+/* Test for warnings for overriding designated initializers:
+   -Woverride-init.  Bug 24010.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-Woverride-init" } */
+
+struct s { int a; int b; int c; };
+union u { char a; long long b; };
+
+struct s s0 = {
+  .a = 1,
+  .b = 2,
+  .a = 3, /* { dg-warning "initialized field overwritten|near init" } */
+  4, /* { dg-warning "initialized field overwritten|near init" } */
+  5
+};
+
+union u u0 = {
+  .a = 1,
+  .b = 2, /* { dg-warning "initialized field overwritten|near init" } */
+  .a = 3 }; /* { dg-warning "initialized field overwritten|near init" } */
+
+int a[5] = {
+  [0] = 1,
+  [1] = 2,
+  [0] = 3, /* { dg-warning "initialized field overwritten|near init" } */
+  [2] = 4
+};
diff --git a/gcc/testsuite/gcc.dg/Woverride-init-2.c b/gcc/testsuite/gcc.dg/Woverride-init-2.c
new file mode 100644
index 0000000..c5490b5
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Woverride-init-2.c
@@ -0,0 +1,28 @@
+/* Test for warnings for overriding designated initializers:
+   -Wextra.  Bug 24010.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-Wextra" } */
+
+struct s { int a; int b; int c; };
+union u { char a; long long b; };
+
+struct s s0 = {
+  .a = 1,
+  .b = 2,
+  .a = 3, /* { dg-warning "initialized field overwritten|near init" } */
+  4, /* { dg-warning "initialized field overwritten|near init" } */
+  5
+};
+
+union u u0 = {
+  .a = 1,
+  .b = 2, /* { dg-warning "initialized field overwritten|near init" } */
+  .a = 3 }; /* { dg-warning "initialized field overwritten|near init" } */
+
+int a[5] = {
+  [0] = 1,
+  [1] = 2,
+  [0] = 3, /* { dg-warning "initialized field overwritten|near init" } */
+  [2] = 4
+};
diff --git a/gcc/testsuite/gcc.dg/Woverride-init-3.c b/gcc/testsuite/gcc.dg/Woverride-init-3.c
new file mode 100644
index 0000000..3fec738
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/Woverride-init-3.c
@@ -0,0 +1,29 @@
+/* Test for warnings for overriding designated initializers: not
+   warned for with -Wextra -Wno-override-init.  Bug 24010.  */
+/* Origin: Joseph Myers <joseph@codesourcery.com> */
+/* { dg-do compile } */
+/* { dg-options "-Wextra -Wno-override-init" } */
+
+struct s { int a; int b; int c; };
+union u { char a; long long b; };
+
+struct s s0 = {
+  .a = 1,
+  .b = 2,
+  .a = 3,
+  4,
+  5
+};
+
+union u u0 = {
+  .a = 1,
+  .b = 2,
+  .a = 3
+};
+
+int a[5] = {
+  [0] = 1,
+  [1] = 2,
+  [0] = 3,
+  [2] = 4
+};