FYI.
Committed this last patch as:
https://jira.oci.oraclecorp.com/browse/OLDIS-21095
I will come up with the update to gcc-13/changes.html for -fstrict-flex-arrays
very soon.
Thanks.
Qing
> On Dec 16, 2022, at 9:49 AM, Qing Zhao via Gcc-patches
> <gcc-patches@gcc.gnu.org> wrote:
>
>
>
>> On Dec 16, 2022, at 4:17 AM, Richard Biener <rguent...@suse.de> wrote:
>>
>> On Thu, 15 Dec 2022, Qing Zhao wrote:
>>
>>>
>>>
>>>> On Dec 15, 2022, at 2:47 AM, Richard Biener <rguent...@suse.de> wrote:
>>>>
>>>> On Wed, 14 Dec 2022, Qing Zhao wrote:
>>>>
>>>>> Hi, Richard,
>>>>>
>>>>> I guess that we now agreed on the following:
>>>>>
>>>>> “ the information that we ran into a trailing array but didn't consider
>>>>> it a flex array because of -fstrict-flex-arrays is always a useful
>>>>> information”
>>>>>
>>>>> The only thing we didn’t decide is:
>>>>>
>>>>> A. Amend such new information to -Warray-bounds when
>>>>> -fstrict-flex-arrays=N (N>0) specified.
>>>>>
>>>>> OR
>>>>>
>>>>> B. Issue such new information with a new warning option
>>>>> -Wstrict-flex-arrays when -fstrict-flex-arrays=N (N>0) specified.
>>>>>
>>>>> My current patch implemented B.
>>>>
>>>> Plus it implements it to specify a different flex-array variant for
>>>> the extra diagnostic.
>>> Could you clarify a little bit on this? (Don’t quite understand…)
>>>>
>>>>> If you think A is better, I will change the patch as A.
>>>>
>>>> I would tend to A since, as I said, it's useful information that
>>>> shouldn't be hidden and not adding an option removes odd combination
>>>> possibilities such as -Wno-array-bounds -Wstrict-flex-arrays.
>>>
>>> With current implementation, the above combination will ONLY report the
>>> misuse of trailing array as flex-array. No out-of-bounds warnings
>>> issued.
>>>
>>>> In particular I find, say, -fstrict-flex-arrays=2 -Wstrict-flex-arrays=1
>>>> hardly useful.
>>>
>>> The above combination will NOT happen, because there is NO level argument
>>> for -Wstrict-flex-arrays.
>>>
>>> The only combination will be: -fstrict-flex-arrays=N -Wstrict-flex-arrays
>>>
>>> When N > 0, -Wstrict-flex-arrays will report any misuse of trailing arrays
>>> as flexible array per the value of N.
>>>>
>>>> But I'm interested in other opinions.
>>>
>>> Adding a separate -Wstrict-flex-arrays will provide users a choice to ONLY
>>> look at the mis-use of trailing arrays as flex-arrays. Without this new
>>> option, such information will be buried into tons of out-of-bounds messges.
>>>
>>> I think this is the major benefit to have one separate new warning
>>> -Wstrict-flex-arrays.
>>>
>>> Do we need to provide the users this choice?
>>
>> Ah, OK - I can see the value of auditing code this way before
>> enabling -fstrict-flex-arrays.
> Yes, I think the major benefit of this option is to help users to identify
> all the places where the trailing arrays are misused as flex-arrays at
> different level of -fstrict-flex-arrays=N, then update their source code
> accordingly. And finally can enable -fstrict-flex-arrays by default.
>>
>>> + if (opts->x_warn_strict_flex_arrays)
>>> + if (opts->x_flag_strict_flex_arrays == 0)
>>> + {
>>> + opts->x_warn_strict_flex_arrays = 0;
>>> + warning_at (UNKNOWN_LOCATION, 0,
>>> + "%<-Wstrict-flex-arrays%> is ignored when"
>>> + " %<-fstrict-flex-arrays%> does not present");
>>
>> "is not present”.
> Okay.
>>
>> The patch is OK with that change.
> Thanks! Will commit the patch after the change.
>>
>> Thanks and sorry for the slow process ...
>
> Thank you for your patience and questions.
> The discussion is very helpful since I was not 100% sure whether this new
> warning is necessary or not in the beginning, but now after this discussion I
> feel confident that it’s a necessary option to be added.
>
> Qing
>
>>
>> Richard.
>>
>>> Thanks.
>>>
>>> Qing
>>>>
>>>> Thanks,
>>>> Richard.
>>>>
>>>>> Let me know your opinion.
>>>>>
>>>>> thanks.
>>>>>
>>>>> Qing
>>>>>
>>>>>
>>>>>> On Dec 14, 2022, at 4:03 AM, Richard Biener <rguent...@suse.de> wrote:
>>>>>>
>>>>>> On Tue, 13 Dec 2022, Qing Zhao wrote:
>>>>>>
>>>>>>> Richard,
>>>>>>>
>>>>>>> Do you have any decision on this one?
>>>>>>> Do we need this warning option For GCC?
>>>>>>
>>>>>> Looking at the testcases it seems that the diagnostic amends
>>>>>> -Warray-bounds diagnostics for trailing but not flexible arrays?
>>>>>> Wouldn't it be better to generally diagnose this, so have
>>>>>> -Warray-bounds, with -fstrict-flex-arrays, for
>>>>>>
>>>>>> struct X { int a[1]; };
>>>>>> int foo (struct X *p)
>>>>>> {
>>>>>> return p->a[1];
>>>>>> }
>>>>>>
>>>>>> emit
>>>>>>
>>>>>> warning: array subscript 1 is above array bounds ...
>>>>>> note: the trailing array is only a flexible array member with
>>>>>> -fno-strict-flex-arrays
>>>>>>
>>>>>> ? Having -Wstrict-flex-arrays=N and N not agree with the
>>>>>> -fstrict-flex-arrays level sounds hardly useful to me but the
>>>>>> information that we ran into a trailing array but didn't consider
>>>>>> it a flex array because of -fstrict-flex-arrays is always a
>>>>>> useful information?
>>>>>>
>>>>>> But maybe I misunderstood this new diagnostic?
>>>>>>
>>>>>> Thanks,
>>>>>> Richard.
>>>>>>
>>>>>>
>>>>>>> thanks.
>>>>>>>
>>>>>>> Qing
>>>>>>>
>>>>>>>> On Dec 6, 2022, at 11:18 AM, Qing Zhao <qing.z...@oracle.com> wrote:
>>>>>>>>
>>>>>>>> '-Wstrict-flex-arrays'
>>>>>>>> Warn about inproper usages of flexible array members according to
>>>>>>>> the LEVEL of the 'strict_flex_array (LEVEL)' attribute attached to
>>>>>>>> the trailing array field of a structure if it's available,
>>>>>>>> otherwise according to the LEVEL of the option
>>>>>>>> '-fstrict-flex-arrays=LEVEL'.
>>>>>>>>
>>>>>>>> This option is effective only when LEVEL is bigger than 0.
>>>>>>>> Otherwise, it will be ignored with a warning.
>>>>>>>>
>>>>>>>> when LEVEL=1, warnings will be issued for a trailing array
>>>>>>>> reference of a structure that have 2 or more elements if the
>>>>>>>> trailing array is referenced as a flexible array member.
>>>>>>>>
>>>>>>>> when LEVEL=2, in addition to LEVEL=1, additional warnings will be
>>>>>>>> issued for a trailing one-element array reference of a structure if
>>>>>>>> the array is referenced as a flexible array member.
>>>>>>>>
>>>>>>>> when LEVEL=3, in addition to LEVEL=2, additional warnings will be
>>>>>>>> issued for a trailing zero-length array reference of a structure if
>>>>>>>> the array is referenced as a flexible array member.
>>>>>>>>
>>>>>>>> gcc/ChangeLog:
>>>>>>>>
>>>>>>>> * doc/invoke.texi: Document -Wstrict-flex-arrays option.
>>>>>>>> * gimple-array-bounds.cc (check_out_of_bounds_and_warn): Add
>>>>>>>> two more
>>>>>>>> arguments.
>>>>>>>> (array_bounds_checker::check_array_ref): Issue warnings for
>>>>>>>> -Wstrict-flex-arrays.
>>>>>>>> * opts.cc (finish_options): Issue warning for unsupported
>>>>>>>> combination
>>>>>>>> of -Wstrict_flex_arrays and -fstrict-flex-array.
>>>>>>>> * tree-vrp.cc (execute_ranger_vrp): Enable the pass when
>>>>>>>> warn_strict_flex_array is true.
>>>>>>>>
>>>>>>>> gcc/c-family/ChangeLog:
>>>>>>>>
>>>>>>>> * c.opt (Wstrict-flex-arrays): New option.
>>>>>>>>
>>>>>>>> gcc/testsuite/ChangeLog:
>>>>>>>>
>>>>>>>> * gcc.dg/Warray-bounds-flex-arrays-1.c: Update testing case with
>>>>>>>> -Wstrict-flex-arrays.
>>>>>>>> * gcc.dg/Warray-bounds-flex-arrays-2.c: Likewise.
>>>>>>>> * gcc.dg/Warray-bounds-flex-arrays-3.c: Likewise.
>>>>>>>> * gcc.dg/Warray-bounds-flex-arrays-4.c: Likewise.
>>>>>>>> * gcc.dg/Warray-bounds-flex-arrays-5.c: Likewise.
>>>>>>>> * gcc.dg/Warray-bounds-flex-arrays-6.c: Likewise.
>>>>>>>> * c-c++-common/Wstrict-flex-arrays.c: New test.
>>>>>>>> * gcc.dg/Wstrict-flex-arrays-2.c: New test.
>>>>>>>> * gcc.dg/Wstrict-flex-arrays-3.c: New test.
>>>>>>>> * gcc.dg/Wstrict-flex-arrays.c: New test.
>>>>>>>> ---
>>>>>>>> gcc/c-family/c.opt | 5 +
>>>>>>>> gcc/doc/invoke.texi | 27 ++++-
>>>>>>>> gcc/gimple-array-bounds.cc | 103 ++++++++++++++----
>>>>>>>> gcc/opts.cc | 8 ++
>>>>>>>> .../c-c++-common/Wstrict-flex-arrays.c | 9 ++
>>>>>>>> .../gcc.dg/Warray-bounds-flex-arrays-1.c | 5 +-
>>>>>>>> .../gcc.dg/Warray-bounds-flex-arrays-2.c | 6 +-
>>>>>>>> .../gcc.dg/Warray-bounds-flex-arrays-3.c | 7 +-
>>>>>>>> .../gcc.dg/Warray-bounds-flex-arrays-4.c | 5 +-
>>>>>>>> .../gcc.dg/Warray-bounds-flex-arrays-5.c | 6 +-
>>>>>>>> .../gcc.dg/Warray-bounds-flex-arrays-6.c | 7 +-
>>>>>>>> gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c | 39 +++++++
>>>>>>>> gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c | 39 +++++++
>>>>>>>> gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c | 39 +++++++
>>>>>>>> gcc/tree-vrp.cc | 2 +-
>>>>>>>> 15 files changed, 273 insertions(+), 34 deletions(-)
>>>>>>>> create mode 100644 gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>>>>>> create mode 100644 gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>>>>>> create mode 100644 gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>>>>>> create mode 100644 gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>>>>>>
>>>>>>>> diff --git a/gcc/c-family/c.opt b/gcc/c-family/c.opt
>>>>>>>> index 0d0ad0a6374..33edeefd285 100644
>>>>>>>> --- a/gcc/c-family/c.opt
>>>>>>>> +++ b/gcc/c-family/c.opt
>>>>>>>> @@ -976,6 +976,11 @@ Wstringop-truncation
>>>>>>>> C ObjC C++ LTO ObjC++ Var(warn_stringop_truncation) Warning Init (1)
>>>>>>>> LangEnabledBy(C ObjC C++ LTO ObjC++, Wall)
>>>>>>>> Warn about truncation in string manipulation functions like strncat
>>>>>>>> and strncpy.
>>>>>>>>
>>>>>>>> +Wstrict-flex-arrays
>>>>>>>> +C C++ Var(warn_strict_flex_arrays) Warning
>>>>>>>> +Warn about inproper usages of flexible array members
>>>>>>>> +according to the level of -fstrict-flex-arrays.
>>>>>>>> +
>>>>>>>> Wsuggest-attribute=format
>>>>>>>> C ObjC C++ ObjC++ Var(warn_suggest_attribute_format) Warning
>>>>>>>> Warn about functions which might be candidates for format attributes.
>>>>>>>> diff --git a/gcc/doc/invoke.texi b/gcc/doc/invoke.texi
>>>>>>>> index 726392409b6..4402b0427ef 100644
>>>>>>>> --- a/gcc/doc/invoke.texi
>>>>>>>> +++ b/gcc/doc/invoke.texi
>>>>>>>> @@ -398,7 +398,7 @@ Objective-C and Objective-C++ Dialects}.
>>>>>>>> -Wstrict-aliasing=n -Wstrict-overflow -Wstrict-overflow=@var{n} @gol
>>>>>>>> -Wstring-compare @gol
>>>>>>>> -Wno-stringop-overflow -Wno-stringop-overread @gol
>>>>>>>> --Wno-stringop-truncation @gol
>>>>>>>> +-Wno-stringop-truncation -Wstrict-flex-arrays @gol
>>>>>>>> -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{|}malloc@r{]}
>>>>>>>> @gol
>>>>>>>> -Wswitch -Wno-switch-bool -Wswitch-default -Wswitch-enum @gol
>>>>>>>> -Wno-switch-outside-range -Wno-switch-unreachable -Wsync-nand @gol
>>>>>>>> @@ -7835,6 +7835,31 @@ however, are not suitable arguments to
>>>>>>>> functions that expect
>>>>>>>> such arrays GCC issues warnings unless it can prove that the use is
>>>>>>>> safe. @xref{Common Variable Attributes}.
>>>>>>>>
>>>>>>>> +@item -Wstrict-flex-arrays
>>>>>>>> +@opindex Wstrict-flex-arrays
>>>>>>>> +@opindex Wno-strict-flex-arrays
>>>>>>>> +Warn about inproper usages of flexible array members
>>>>>>>> +according to the @var{level} of the @code{strict_flex_array
>>>>>>>> (@var{level})}
>>>>>>>> +attribute attached to the trailing array field of a structure if it's
>>>>>>>> +available, otherwise according to the @var{level} of the option
>>>>>>>> +@option{-fstrict-flex-arrays=@var{level}}.
>>>>>>>> +
>>>>>>>> +This option is effective only when @var{level} is bigger than 0.
>>>>>>>> Otherwise,
>>>>>>>> +it will be ignored with a warning.
>>>>>>>> +
>>>>>>>> +when @var{level}=1, warnings will be issued for a trailing array
>>>>>>>> reference
>>>>>>>> +of a structure that have 2 or more elements if the trailing array is
>>>>>>>> referenced
>>>>>>>> +as a flexible array member.
>>>>>>>> +
>>>>>>>> +when @var{level}=2, in addition to @var{level}=1, additional warnings
>>>>>>>> will be
>>>>>>>> +issued for a trailing one-element array reference of a structure
>>>>>>>> +if the array is referenced as a flexible array member.
>>>>>>>> +
>>>>>>>> +when @var{level}=3, in addition to @var{level}=2, additional warnings
>>>>>>>> will be
>>>>>>>> +issued for a trailing zero-length array reference of a structure
>>>>>>>> +if the array is referenced as a flexible array member.
>>>>>>>> +
>>>>>>>> +
>>>>>>>> @item
>>>>>>>> -Wsuggest-attribute=@r{[}pure@r{|}const@r{|}noreturn@r{|}format@r{|}cold@r{|}malloc@r{]}
>>>>>>>> @opindex Wsuggest-attribute=
>>>>>>>> @opindex Wno-suggest-attribute=
>>>>>>>> diff --git a/gcc/gimple-array-bounds.cc b/gcc/gimple-array-bounds.cc
>>>>>>>> index db3459af325..825f11331b5 100644
>>>>>>>> --- a/gcc/gimple-array-bounds.cc
>>>>>>>> +++ b/gcc/gimple-array-bounds.cc
>>>>>>>> @@ -252,25 +252,34 @@ get_up_bounds_for_array_ref (tree ref, tree
>>>>>>>> *decl,
>>>>>>>>
>>>>>>>> /* Given the LOW_SUB_ORG, LOW_SUB and UP_SUB, and the computed UP_BOUND
>>>>>>>> and UP_BOUND_P1, check whether the array reference REF is out of bound.
>>>>>>>> - Issue warnings if out of bound, return TRUE if warnings are
>>>>>>>> issued. */
>>>>>>>> + When out of bounds, set OUT_OF_BOUND to true.
>>>>>>>> + Issue warnings if FOR_ARRAY_BOUND is true.
>>>>>>>> + return TRUE if warnings are issued. */
>>>>>>>> +
>>>>>>>>
>>>>>>>> static bool
>>>>>>>> check_out_of_bounds_and_warn (location_t location, tree ref,
>>>>>>>> tree low_sub_org, tree low_sub, tree
>>>>>>>> up_sub,
>>>>>>>> tree up_bound, tree up_bound_p1,
>>>>>>>> const value_range *vr,
>>>>>>>> - bool ignore_off_by_one)
>>>>>>>> + bool ignore_off_by_one, bool
>>>>>>>> for_array_bound,
>>>>>>>> + bool *out_of_bound)
>>>>>>>> {
>>>>>>>> tree low_bound = array_ref_low_bound (ref);
>>>>>>>> tree artype = TREE_TYPE (TREE_OPERAND (ref, 0));
>>>>>>>>
>>>>>>>> bool warned = false;
>>>>>>>> + *out_of_bound = false;
>>>>>>>>
>>>>>>>> /* Empty array. */
>>>>>>>> if (up_bound && tree_int_cst_equal (low_bound, up_bound_p1))
>>>>>>>> - warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> - "array subscript %E is outside array bounds of
>>>>>>>> %qT",
>>>>>>>> - low_sub_org, artype);
>>>>>>>> + {
>>>>>>>> + *out_of_bound = true;
>>>>>>>> + if (for_array_bound)
>>>>>>>> + warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> + "array subscript %E is outside array"
>>>>>>>> + " bounds of %qT", low_sub_org, artype);
>>>>>>>> + }
>>>>>>>>
>>>>>>>> if (warned)
>>>>>>>> ; /* Do nothing. */
>>>>>>>> @@ -283,24 +292,33 @@ check_out_of_bounds_and_warn (location_t
>>>>>>>> location, tree ref,
>>>>>>>> : tree_int_cst_le (up_bound, up_sub))
>>>>>>>> && TREE_CODE (low_sub) == INTEGER_CST
>>>>>>>> && tree_int_cst_le (low_sub, low_bound))
>>>>>>>> - warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> - "array subscript [%E, %E] is outside "
>>>>>>>> - "array bounds of %qT",
>>>>>>>> - low_sub, up_sub, artype);
>>>>>>>> + {
>>>>>>>> + *out_of_bound = true;
>>>>>>>> + warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> + "array subscript [%E, %E] is outside "
>>>>>>>> + "array bounds of %qT",
>>>>>>>> + low_sub, up_sub, artype);
>>>>>>>> + }
>>>>>>>> }
>>>>>>>> else if (up_bound
>>>>>>>> && TREE_CODE (up_sub) == INTEGER_CST
>>>>>>>> && (ignore_off_by_one
>>>>>>>> ? !tree_int_cst_le (up_sub, up_bound_p1)
>>>>>>>> : !tree_int_cst_le (up_sub, up_bound)))
>>>>>>>> - warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> - "array subscript %E is above array bounds of
>>>>>>>> %qT",
>>>>>>>> - up_sub, artype);
>>>>>>>> + {
>>>>>>>> + *out_of_bound = true;
>>>>>>>> + warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> + "array subscript %E is above array bounds of
>>>>>>>> %qT",
>>>>>>>> + up_sub, artype);
>>>>>>>> + }
>>>>>>>> else if (TREE_CODE (low_sub) == INTEGER_CST
>>>>>>>> && tree_int_cst_lt (low_sub, low_bound))
>>>>>>>> - warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> - "array subscript %E is below array bounds of
>>>>>>>> %qT",
>>>>>>>> - low_sub, artype);
>>>>>>>> + {
>>>>>>>> + *out_of_bound = true;
>>>>>>>> + warned = warning_at (location, OPT_Warray_bounds_,
>>>>>>>> + "array subscript %E is below array bounds of
>>>>>>>> %qT",
>>>>>>>> + low_sub, artype);
>>>>>>>> + }
>>>>>>>> return warned;
>>>>>>>> }
>>>>>>>>
>>>>>>>> @@ -333,14 +351,21 @@ array_bounds_checker::check_array_ref
>>>>>>>> (location_t location, tree ref,
>>>>>>>>
>>>>>>>> tree arg = TREE_OPERAND (ref, 0);
>>>>>>>> const bool compref = TREE_CODE (arg) == COMPONENT_REF;
>>>>>>>> + unsigned int strict_flex_array_level = flag_strict_flex_arrays;
>>>>>>>>
>>>>>>>> if (compref)
>>>>>>>> - /* Try to determine special array member type for this
>>>>>>>> COMPONENT_REF. */
>>>>>>>> - sam = component_ref_sam_type (arg);
>>>>>>>> + {
>>>>>>>> + /* Try to determine special array member type for this
>>>>>>>> COMPONENT_REF. */
>>>>>>>> + sam = component_ref_sam_type (arg);
>>>>>>>> + /* Get the level of strict_flex_array for this array field. */
>>>>>>>> + tree afield_decl = TREE_OPERAND (arg, 1);
>>>>>>>> + strict_flex_array_level = strict_flex_array_level_of
>>>>>>>> (afield_decl);
>>>>>>>> + }
>>>>>>>>
>>>>>>>> get_up_bounds_for_array_ref (ref, &decl, &up_bound, &up_bound_p1);
>>>>>>>>
>>>>>>>> bool warned = false;
>>>>>>>> + bool out_of_bound = false;
>>>>>>>>
>>>>>>>> tree artype = TREE_TYPE (TREE_OPERAND (ref, 0));
>>>>>>>> tree low_sub_org = TREE_OPERAND (ref, 1);
>>>>>>>> @@ -361,7 +386,8 @@ array_bounds_checker::check_array_ref (location_t
>>>>>>>> location, tree ref,
>>>>>>>> warned = check_out_of_bounds_and_warn (location, ref,
>>>>>>>> low_sub_org, low_sub, up_sub,
>>>>>>>> up_bound, up_bound_p1, vr,
>>>>>>>> - ignore_off_by_one);
>>>>>>>> + ignore_off_by_one,
>>>>>>>> warn_array_bounds,
>>>>>>>> + &out_of_bound);
>>>>>>>>
>>>>>>>>
>>>>>>>> if (!warned && sam == special_array_member::int_0)
>>>>>>>> @@ -373,19 +399,56 @@ array_bounds_checker::check_array_ref
>>>>>>>> (location_t location, tree ref,
>>>>>>>> "of an interior zero-length array %qT")),
>>>>>>>> low_sub, artype);
>>>>>>>>
>>>>>>>> - if (warned)
>>>>>>>> + if (warned || out_of_bound)
>>>>>>>> {
>>>>>>>> - if (dump_file && (dump_flags & TDF_DETAILS))
>>>>>>>> + if (warned && dump_file && (dump_flags & TDF_DETAILS))
>>>>>>>> {
>>>>>>>> fprintf (dump_file, "Array bound warning for ");
>>>>>>>> dump_generic_expr (MSG_NOTE, TDF_SLIM, ref);
>>>>>>>> fprintf (dump_file, "\n");
>>>>>>>> }
>>>>>>>>
>>>>>>>> + /* issue warnings for -Wstrict-flex-arrays according to the
>>>>>>>> level of
>>>>>>>> + flag_strict_flex_arrays. */
>>>>>>>> + if (out_of_bound && warn_strict_flex_arrays)
>>>>>>>> + switch (strict_flex_array_level)
>>>>>>>> + {
>>>>>>>> + case 3:
>>>>>>>> + /* Issue additional warnings for trailing arrays [0]. */
>>>>>>>> + if (sam == special_array_member::trail_0)
>>>>>>>> + warned = warning_at (location, OPT_Wstrict_flex_arrays,
>>>>>>>> + "trailing array %qT should not be
>>>>>>>> used as "
>>>>>>>> + "a flexible array member for level
>>>>>>>> 3",
>>>>>>>> + artype);
>>>>>>>> + /* FALLTHROUGH. */
>>>>>>>> + case 2:
>>>>>>>> + /* Issue additional warnings for trailing arrays [1]. */
>>>>>>>> + if (sam == special_array_member::trail_1)
>>>>>>>> + warned = warning_at (location, OPT_Wstrict_flex_arrays,
>>>>>>>> + "trailing array %qT should not be
>>>>>>>> used as "
>>>>>>>> + "a flexible array member for level 2
>>>>>>>> and "
>>>>>>>> + "above", artype);
>>>>>>>> + /* FALLTHROUGH. */
>>>>>>>> + case 1:
>>>>>>>> + /* Issue warnings for trailing arrays [n]. */
>>>>>>>> + if (sam == special_array_member::trail_n)
>>>>>>>> + warned = warning_at (location, OPT_Wstrict_flex_arrays,
>>>>>>>> + "trailing array %qT should not be
>>>>>>>> used as "
>>>>>>>> + "a flexible array member for level 1
>>>>>>>> and "
>>>>>>>> + "above", artype);
>>>>>>>> + break;
>>>>>>>> + case 0:
>>>>>>>> + /* Do nothing. */
>>>>>>>> + break;
>>>>>>>> + default:
>>>>>>>> + gcc_unreachable ();
>>>>>>>> + }
>>>>>>>> +
>>>>>>>> /* Avoid more warnings when checking more significant subscripts
>>>>>>>> of the same expression. */
>>>>>>>> ref = TREE_OPERAND (ref, 0);
>>>>>>>> suppress_warning (ref, OPT_Warray_bounds_);
>>>>>>>> + suppress_warning (ref, OPT_Wstrict_flex_arrays);
>>>>>>>>
>>>>>>>> if (decl)
>>>>>>>> ref = decl;
>>>>>>>> diff --git a/gcc/opts.cc b/gcc/opts.cc
>>>>>>>> index 73fc97756e4..8db53ad6c77 100644
>>>>>>>> --- a/gcc/opts.cc
>>>>>>>> +++ b/gcc/opts.cc
>>>>>>>> @@ -1411,6 +1411,14 @@ finish_options (struct gcc_options *opts,
>>>>>>>> struct gcc_options *opts_set,
>>>>>>>> opts->x_profile_flag = 0;
>>>>>>>> }
>>>>>>>>
>>>>>>>> + if (opts->x_warn_strict_flex_arrays)
>>>>>>>> + if (opts->x_flag_strict_flex_arrays == 0)
>>>>>>>> + {
>>>>>>>> + opts->x_warn_strict_flex_arrays = 0;
>>>>>>>> + warning_at (UNKNOWN_LOCATION, 0,
>>>>>>>> + "%<-Wstrict-flex-arrays%> is ignored when"
>>>>>>>> + " %<-fstrict-flex-arrays%> does not present");
>>>>>>>> + }
>>>>>>>>
>>>>>>>> diagnose_options (opts, opts_set, loc);
>>>>>>>> }
>>>>>>>> diff --git a/gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>>>>>> b/gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>>>>>> new file mode 100644
>>>>>>>> index 00000000000..72b4b7c6406
>>>>>>>> --- /dev/null
>>>>>>>> +++ b/gcc/testsuite/c-c++-common/Wstrict-flex-arrays.c
>>>>>>>> @@ -0,0 +1,9 @@
>>>>>>>> +/* Test the usage of option -Wstrict-flex-arrays. */
>>>>>>>> +/* { dg-do compile } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays" } */
>>>>>>>> +
>>>>>>>> +int main(int argc, char *argv[])
>>>>>>>> +{
>>>>>>>> + return 0;
>>>>>>>> +}
>>>>>>>> +/* { dg-warning "is ignored when \'-fstrict-flex-arrays\' does not
>>>>>>>> present" "" { target *-*-* } 0 } */
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>>>>>> index d36ba4d86cb..65c9fec43af 100644
>>>>>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-1.c
>>>>>>>> @@ -1,6 +1,6 @@
>>>>>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds. */
>>>>>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds + -Wstrict-flex-arrays.
>>>>>>>> */
>>>>>>>> /* { dg-do compile} */
>>>>>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=1 -Warray-bounds" } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=1
>>>>>>>> -Warray-bounds" } */
>>>>>>>>
>>>>>>>> struct trailing_array_1 {
>>>>>>>> int a;
>>>>>>>> @@ -32,6 +32,7 @@ void __attribute__((__noinline__)) stuff(
>>>>>>>> struct trailing_array_4 *trailing_flex)
>>>>>>>> {
>>>>>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>>>>>> array bounds of" } */
>>>>>>>> + /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_1->c[2] = 2; /* { dg-bogus "array subscript " } */
>>>>>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>>>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>>>>>> index f63206e1948..2b5a895c598 100644
>>>>>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-2.c
>>>>>>>> @@ -1,6 +1,6 @@
>>>>>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds. */
>>>>>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds + -Wstrict-flex-arrays.
>>>>>>>> */
>>>>>>>> /* { dg-do compile } */
>>>>>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=2 -Warray-bounds" } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=2
>>>>>>>> -Warray-bounds" } */
>>>>>>>>
>>>>>>>> struct trailing_array_1 {
>>>>>>>> int a;
>>>>>>>> @@ -32,7 +32,9 @@ void __attribute__((__noinline__)) stuff(
>>>>>>>> struct trailing_array_4 *trailing_flex)
>>>>>>>> {
>>>>>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>>>>>> array bounds of" } */
>>>>>>>> + /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_1->c[2] = 2; /* { dg-warning "array subscript 2 is above
>>>>>>>> array bounds of" } */
>>>>>>>> + /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>>>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>>>>>
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>>>>>> index e3273714e8b..25b903f2615 100644
>>>>>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-3.c
>>>>>>>> @@ -1,6 +1,6 @@
>>>>>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds. */
>>>>>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds + -Wstrict-flex-arrays.
>>>>>>>> */
>>>>>>>> /* { dg-do compile } */
>>>>>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=3 -Warray-bounds" } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=3
>>>>>>>> -Warray-bounds" } */
>>>>>>>>
>>>>>>>> struct trailing_array_1 {
>>>>>>>> int a;
>>>>>>>> @@ -32,8 +32,11 @@ void __attribute__((__noinline__)) stuff(
>>>>>>>> struct trailing_array_4 *trailing_flex)
>>>>>>>> {
>>>>>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>>>>>> array bounds of" } */
>>>>>>>> + /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_1->c[2] = 2; /*{ dg-warning "array subscript 2 is above array
>>>>>>>> bounds of" } */
>>>>>>>> + /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_0->c[1] = 1; /*{ dg-warning "array subscript 1 is outside
>>>>>>>> array bounds of" } */
>>>>>>>> + /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 3" "" { target *-*-* } .-1 } */
>>>>>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript" } */
>>>>>>>>
>>>>>>>> }
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>>>>>> index cabaea77dc2..5fc500a19ca 100644
>>>>>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-4.c
>>>>>>>> @@ -1,6 +1,6 @@
>>>>>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds=2. */
>>>>>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds=2 +
>>>>>>>> -Wstrict-flex-arrays. */
>>>>>>>> /* { dg-do compile } */
>>>>>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=1 -Warray-bounds=2" } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=1
>>>>>>>> -Warray-bounds=2" } */
>>>>>>>>
>>>>>>>> struct trailing_array_1 {
>>>>>>>> int a;
>>>>>>>> @@ -32,6 +32,7 @@ void __attribute__((__noinline__)) stuff(
>>>>>>>> struct trailing_array_4 *trailing_flex)
>>>>>>>> {
>>>>>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>>>>>> array bounds of" } */
>>>>>>>> + /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_1->c[2] = 2; /* { dg-bogus "array subscript " } */
>>>>>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>>>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>>>>>> index 8b7db6e4f39..30bb4ca8832 100644
>>>>>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-5.c
>>>>>>>> @@ -1,6 +1,6 @@
>>>>>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds=2. */
>>>>>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds=2 +
>>>>>>>> -Wstrict-flex-arrays. */
>>>>>>>> /* { dg-do compile } */
>>>>>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=2 -Warray-bounds=2" } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=2
>>>>>>>> -Warray-bounds=2" } */
>>>>>>>>
>>>>>>>> struct trailing_array_1 {
>>>>>>>> int a;
>>>>>>>> @@ -32,7 +32,9 @@ void __attribute__((__noinline__)) stuff(
>>>>>>>> struct trailing_array_4 *trailing_flex)
>>>>>>>> {
>>>>>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above array
>>>>>>>> bounds of" } */
>>>>>>>> + /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_1->c[2] = 2; /*{ dg-warning "array subscript 2 is above array
>>>>>>>> bounds of" } */
>>>>>>>> + /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_0->c[1] = 1; /* { dg-bogus "array subscript " } */
>>>>>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>>>>>
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>>>>>> index 035bf481396..e847a44516e 100644
>>>>>>>> --- a/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Warray-bounds-flex-arrays-6.c
>>>>>>>> @@ -1,6 +1,6 @@
>>>>>>>> -/* Test -fstrict-flex-arrays + -Warray-bounds=2. */
>>>>>>>> +/* Test -fstrict-flex-arrays + -Warray-bounds=2 +
>>>>>>>> -Wstrict-flex-arrays. */
>>>>>>>> /* { dg-do compile } */
>>>>>>>> -/* { dg-options "-O2 -fstrict-flex-arrays=3 -Warray-bounds=2" } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=3
>>>>>>>> -Warray-bounds=2" } */
>>>>>>>>
>>>>>>>> struct trailing_array_1 {
>>>>>>>> int a;
>>>>>>>> @@ -32,8 +32,11 @@ void __attribute__((__noinline__)) stuff(
>>>>>>>> struct trailing_array_4 *trailing_flex)
>>>>>>>> {
>>>>>>>> normal->c[5] = 5; /*{ dg-warning "array subscript 5 is above
>>>>>>>> array bounds of" } */
>>>>>>>> + /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_1->c[2] = 2; /*{ dg-warning "array subscript 2 is above array
>>>>>>>> bounds of" } */
>>>>>>>> + /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 2 and above" "" { target *-*-* } .-1 }
>>>>>>>> */
>>>>>>>> trailing_0->c[1] = 1; /*{ dg-warning "array subscript 1 is outside
>>>>>>>> array bounds of" } */
>>>>>>>> + /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 3" "" { target *-*-* } .-1 } */
>>>>>>>> trailing_flex->c[10] = 10; /* { dg-bogus "array subscript " } */
>>>>>>>>
>>>>>>>> }
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>>>>>> new file mode 100644
>>>>>>>> index 00000000000..2e241f96208
>>>>>>>> --- /dev/null
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-2.c
>>>>>>>> @@ -0,0 +1,39 @@
>>>>>>>> +/* Test -Wstrict-flex-arrays. */
>>>>>>>> +/* { dg-do compile } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=2" } */
>>>>>>>> +
>>>>>>>> +struct trailing_array_1 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[4];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct trailing_array_2 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[1];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct trailing_array_3 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[0];
>>>>>>>> +};
>>>>>>>> +struct trailing_array_4 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +void __attribute__((__noinline__)) stuff(
>>>>>>>> + struct trailing_array_1 *normal,
>>>>>>>> + struct trailing_array_2 *trailing_1,
>>>>>>>> + struct trailing_array_3 *trailing_0,
>>>>>>>> + struct trailing_array_4 *trailing_flex)
>>>>>>>> +{
>>>>>>>> + normal->c[5] = 5; /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" } */
>>>>>>>> + trailing_1->c[2] = 2; /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 2 and above" } */
>>>>>>>> + trailing_0->c[1] = 1; /* { dg-bogus "should not be used as a
>>>>>>>> flexible array member for level 2 and above" } */
>>>>>>>> + trailing_flex->c[10] = 10; /* { dg-bogus "should not be used as a
>>>>>>>> flexible array member for level 2 and above" } */
>>>>>>>> +
>>>>>>>> +}
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>>>>>> new file mode 100644
>>>>>>>> index 00000000000..97eb65ba0a9
>>>>>>>> --- /dev/null
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays-3.c
>>>>>>>> @@ -0,0 +1,39 @@
>>>>>>>> +/* Test -Wstrict-flex-arrays. */
>>>>>>>> +/* { dg-do compile } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=3" } */
>>>>>>>> +
>>>>>>>> +struct trailing_array_1 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[4];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct trailing_array_2 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[1];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct trailing_array_3 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[0];
>>>>>>>> +};
>>>>>>>> +struct trailing_array_4 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +void __attribute__((__noinline__)) stuff(
>>>>>>>> + struct trailing_array_1 *normal,
>>>>>>>> + struct trailing_array_2 *trailing_1,
>>>>>>>> + struct trailing_array_3 *trailing_0,
>>>>>>>> + struct trailing_array_4 *trailing_flex)
>>>>>>>> +{
>>>>>>>> + normal->c[5] = 5; /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" } */
>>>>>>>> + trailing_1->c[2] = 2; /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 2 and above" } */
>>>>>>>> + trailing_0->c[1] = 1; /* { dg-warning "should not be used as a
>>>>>>>> flexible array member for level 3" } */
>>>>>>>> + trailing_flex->c[10] = 10; /* { dg-bogus "should not be used as a
>>>>>>>> flexible array member for level 3" } */
>>>>>>>> +
>>>>>>>> +}
>>>>>>>> diff --git a/gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>>>>>> b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>>>>>> new file mode 100644
>>>>>>>> index 00000000000..110fdc72778
>>>>>>>> --- /dev/null
>>>>>>>> +++ b/gcc/testsuite/gcc.dg/Wstrict-flex-arrays.c
>>>>>>>> @@ -0,0 +1,39 @@
>>>>>>>> +/* Test -Wstrict-flex-arrays. */
>>>>>>>> +/* { dg-do compile } */
>>>>>>>> +/* { dg-options "-O2 -Wstrict-flex-arrays -fstrict-flex-arrays=1" } */
>>>>>>>> +
>>>>>>>> +struct trailing_array_1 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[4];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct trailing_array_2 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[1];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +struct trailing_array_3 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[0];
>>>>>>>> +};
>>>>>>>> +struct trailing_array_4 {
>>>>>>>> + int a;
>>>>>>>> + int b;
>>>>>>>> + int c[];
>>>>>>>> +};
>>>>>>>> +
>>>>>>>> +void __attribute__((__noinline__)) stuff(
>>>>>>>> + struct trailing_array_1 *normal,
>>>>>>>> + struct trailing_array_2 *trailing_1,
>>>>>>>> + struct trailing_array_3 *trailing_0,
>>>>>>>> + struct trailing_array_4 *trailing_flex)
>>>>>>>> +{
>>>>>>>> + normal->c[5] = 5; /*{ dg-warning "should not be used as a
>>>>>>>> flexible array member for level 1 and above" } */
>>>>>>>> + trailing_1->c[2] = 2; /* { dg-bogus "should not be used as a
>>>>>>>> flexible array member for level 1 and above" } */
>>>>>>>> + trailing_0->c[1] = 1; /* { dg-bogus "should not be used as a
>>>>>>>> flexible array member for level 1 and above" } */
>>>>>>>> + trailing_flex->c[10] = 10; /* { dg-bogus "should not be used as a
>>>>>>>> flexible array member for level 1 and above" } */
>>>>>>>> +
>>>>>>>> +}
>>>>>>>> diff --git a/gcc/tree-vrp.cc b/gcc/tree-vrp.cc
>>>>>>>> index 3846dc1d849..e6c6c5a301d 100644
>>>>>>>> --- a/gcc/tree-vrp.cc
>>>>>>>> +++ b/gcc/tree-vrp.cc
>>>>>>>> @@ -1087,7 +1087,7 @@ execute_ranger_vrp (struct function *fun, bool
>>>>>>>> warn_array_bounds_p,
>>>>>>>> if (dump_file && (dump_flags & TDF_DETAILS))
>>>>>>>> ranger->dump (dump_file);
>>>>>>>>
>>>>>>>> - if (warn_array_bounds && warn_array_bounds_p)
>>>>>>>> + if ((warn_array_bounds || warn_strict_flex_arrays) &&
>>>>>>>> warn_array_bounds_p)
>>>>>>>> {
>>>>>>>> // Set all edges as executable, except those ranger says aren't.
>>>>>>>> int non_exec_flag = ranger->non_executable_edge_flag;
>>>>>>>> --
>>>>>>>> 2.31.1
>>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>
>>>>>> --
>>>>>> Richard Biener <rguent...@suse.de>
>>>>>> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461
>>>>>> Nuernberg,
>>>>>> Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
>>>>>> HRB 36809 (AG Nuernberg)
>>>>>
>>>>>
>>>>
>>>> --
>>>> Richard Biener <rguent...@suse.de>
>>>> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
>>>> Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
>>>> HRB 36809 (AG Nuernberg)
>>>
>>>
>>
>> --
>> Richard Biener <rguent...@suse.de>
>> SUSE Software Solutions Germany GmbH, Frankenstrasse 146, 90461 Nuernberg,
>> Germany; GF: Ivo Totev, Andrew Myers, Andrew McDonald, Boudien Moerman;
>> HRB 36809 (AG Nuernberg)
