[Bug c/64709] Bogus -Wmissing-field-initializers warning

[Bug c/64709] Bogus -Wmissing-field-initializers warning

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

--- Comment #1 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
We shouldn't warn on { 0 }.

[Bug c/64709] [5 Regression] Bogus -Wmissing-field-initializers warning

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
   Target Milestone|---                         |5.0
            Summary|Bogus                       |[5 Regression] Bogus
                   |-Wmissing-field-initializer |-Wmissing-field-initializer
                   |s warning                   |s warning

[Bug c/64709] [5 Regression] Bogus -Wmissing-field-initializers warning

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

Jakub Jelinek <jakub at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |jakub at gcc dot gnu.org,
                   |                            |jsm28 at gcc dot gnu.org

--- Comment #2 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
I wonder if that might not be undesirable in some cases, perhaps allow the
users to choose?  -Wmissing-field-initializers ==
-Wmissing-field-initializers=1 (enabled in -Wall or where) would do what you
suggest, -Wmissing-field-initializers=2 would warn even for this?

[Bug c/64709] [5 Regression] Bogus -Wmissing-field-initializers warning

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2015-01-21
     Ever confirmed|0                           |1

--- Comment #3 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Maybe.  There's an RFE for -Wmissing-field-initializers=2 in PR39589, though
that speaks about allowing the warning with designated initializers.

[Bug c/64709] [5 Regression] Bogus -Wmissing-field-initializers warning

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

--- Comment #4 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
BTW, untested patch (dg.exp passes).  

diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
index f39dfdd..53d1a16 100644
--- a/gcc/c/c-typeck.c
+++ b/gcc/c/c-typeck.c
@@ -7556,20 +7556,28 @@ pop_init_level (location_t loc, int implicit,
     }
     }

-  /* Initialization with { } counts as zeroinit.  */
-  if (vec_safe_length (constructor_elements) == 0)
-    constructor_zeroinit = 1;
-  /* If the constructor has more than one element, it can't be { 0 }.  */
-  else if (vec_safe_length (constructor_elements) != 1)
-    constructor_zeroinit = 0;
+  switch (vec_safe_length (constructor_elements))
+    {
+    case 0:
+      /* Initialization with { } counts as zeroinit.  */
+      constructor_zeroinit = 1;
+      break;
+    case 1:
+      /* This might be zeroinit as well.  */
+      if (integer_zerop ((*constructor_elements)[0].value))
+    constructor_zeroinit = 1;
+      break;
+    default:
+      /* If the constructor has more than one element, it can't be { 0 }.  */
+      constructor_zeroinit = 0;
+      break;
+    }

   /* Warn when some structs are initialized with direct aggregation.  */
   if (!implicit && found_missing_braces && warn_missing_braces
       && !constructor_zeroinit)
-    {
-      warning_init (loc, OPT_Wmissing_braces,
-            "missing braces around initializer");
-    }
+    warning_init (loc, OPT_Wmissing_braces,
+          "missing braces around initializer");

   /* Warn when some struct elements are implicitly initialized to zero.  */
   if (warn_missing_field_initializers

[Bug c/64709] [5 Regression] Bogus -Wmissing-field-initializers warning

[jakub at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

--- Comment #5 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
What value will constructor_zeroinit have if it has a single element which is
not integer_zerop?  Should we set it to 0 in that case?

[Bug c/64709] [5 Regression] Bogus -Wmissing-field-initializers warning

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

Marek Polacek <mpolacek at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|NEW                         |RESOLVED
         Resolution|---                         |FIXED

--- Comment #7 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Fixed.

[Bug c/64709] [5 Regression] Bogus -Wmissing-field-initializers warning

[mpolacek at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64709

--- Comment #6 from Marek Polacek <mpolacek at gcc dot gnu.org> ---
Author: mpolacek
Date: Thu Jan 29 21:02:21 2015
New Revision: 220263

URL: https://gcc.gnu.org/viewcvs?rev=220263&root=gcc&view=rev
Log:
    PR c/64709
    * c-typeck.c (pop_init_level): If constructor_elements has
    exactly one element with integer_zerop value, set constructor_zeroinit
    to 1.  Remove braces around warning_init call.

    * gcc.dg/pr64709.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr64709.c
Modified:
    trunk/gcc/c/ChangeLog
    trunk/gcc/c/c-typeck.c
    trunk/gcc/testsuite/ChangeLog