[gcc r13-2556] Fix "address will never be NULL" warning

[Jan-Benedict Glaw <jbglaw@gcc.gnu.org>]

https://gcc.gnu.org/g:c2c3e4f6698925c8c969d8525677fbfe98f78909

commit r13-2556-gc2c3e4f6698925c8c969d8525677fbfe98f78909
Author: Jan-Benedict Glaw <jbglaw@lug-owl.de>
Date:   Fri Sep 9 10:27:27 2022 +0200

    Fix "address will never be NULL" warning
    
    The mingw32 port is the only port to have TARGET_OVERRIDES_FORMAT_ATTRIBUTES
    defined. When this macro is defined, it will never evaluate to NULL and produce
    a warning: "error: the address of 'mingw_format_attribute_overrides' will never
    be NULL [-Werror=address]"
    
      Also, when TARGET_OVERRIDES_FORMAT_ATTRIBUTES is defined,
    TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT must be defined as well. Add that
    requirement to the docs.
    
    2022-09-07  Jan-Benedict Glaw  <jbglaw@lug-owl.de>
    
    gcc/c-family/ChangeLog:
            * c-format.cc (convert_format_name_to_system_name): Fix warning.
    gcc/ChangeLog:
            * doc/tm.texi.in (TARGET_OVERRIDES_FORMAT_ATTRIBUTES): Document requirement
            of TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT being defined as well.
            * doc/tm.texi: Regenerate.

Diff:
---
 gcc/c-family/c-format.cc | 3 +--
 gcc/doc/tm.texi          | 3 ++-
 gcc/doc/tm.texi.in       | 3 ++-
 3 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/gcc/c-family/c-format.cc b/gcc/c-family/c-format.cc
index 68b94da40cc..a6c380bf1c8 100644
--- a/gcc/c-family/c-format.cc
+++ b/gcc/c-family/c-format.cc
@@ -5111,8 +5111,7 @@ convert_format_name_to_system_name (const char *attr_name)
 
 #ifdef TARGET_OVERRIDES_FORMAT_ATTRIBUTES
   /* Check if format attribute is overridden by target.  */
-  if (TARGET_OVERRIDES_FORMAT_ATTRIBUTES != NULL
-      && TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT > 0)
+  if (TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT > 0)
     {
       for (i = 0; i < TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT; ++i)
         {
diff --git a/gcc/doc/tm.texi b/gcc/doc/tm.texi
index e47bf28089a..858bfb80cec 100644
--- a/gcc/doc/tm.texi
+++ b/gcc/doc/tm.texi
@@ -12043,7 +12043,8 @@ If defined, this macro is the number of entries in
 If defined, this macro is the name of a global variable containing
 target-specific format overrides for the @option{-Wformat} option. The
 default is to have no target-specific format overrides. If defined,
-@code{TARGET_FORMAT_TYPES} must be defined, too.
+@code{TARGET_FORMAT_TYPES} and @code{TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT}
+must be defined, too.
 @end defmac
 
 @defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT
diff --git a/gcc/doc/tm.texi.in b/gcc/doc/tm.texi.in
index 5312059ea79..21b849ea32a 100644
--- a/gcc/doc/tm.texi.in
+++ b/gcc/doc/tm.texi.in
@@ -7836,7 +7836,8 @@ If defined, this macro is the number of entries in
 If defined, this macro is the name of a global variable containing
 target-specific format overrides for the @option{-Wformat} option. The
 default is to have no target-specific format overrides. If defined,
-@code{TARGET_FORMAT_TYPES} must be defined, too.
+@code{TARGET_FORMAT_TYPES} and @code{TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT}
+must be defined, too.
 @end defmac
 
 @defmac TARGET_OVERRIDES_FORMAT_ATTRIBUTES_COUNT