Am Freitag, den 11.06.2021, 21:25 +0200 schrieb Martin Uecker:
> (PING. In case you missed this. Sorry, forgot to CC you.)
>
> Am Montag, den 24.05.2021, 08:05 +0200 schrieb Martin Uecker:
> > Hi Joseph,
> >
> > I found some time to update this patch. The only real change
> > of the patch is the qualifier in the conditional expression for
> > pointer to arrays in C2X. All the rest are the warnings,
> > which were wrong in the last version.
> >
> > I hope I got this correct this time in combination with
> > -pedantic-errors and -Wc11-c2x-compat.
> >
> > Martin
> >
> >
> > 2021-05-16 Martin Uecker <muec...@gwdg.de>
> >
> > gcc/c/
> > PR c/98397
> > * c-typeck.c (comp_target_types): Change pedwarn to pedwarn_c11
> > for pointers to arrays with qualifiers.
> > (build_conditional_expr): For C23 don't lose qualifiers for pointers
> > to arrays when the other pointer is a void pointer. Update warnings.
> > (convert_for_assignment): Update warnings for C2X when converting from
> > void* with qualifiers to a pointer to array with the same qualifiers.
> >
> > gcc/testsuite/
> > PR c/98397
> > * gcc.dg/c11-qual-1.c: New test.
> > * gcc.dg/c2x-qual-1.c: New test.
> > * gcc.dg/c2x-qual-2.c: New test.
> > * gcc.dg/c2x-qual-3.c: New test.
> > * gcc.dg/c2x-qual-4.c: New test.
> > * gcc.dg/c2x-qual-5.c: New test.
> > * gcc.dg/c2x-qual-6.c: New test.
> > * gcc.dg/pointer-array-quals-1.c: Remove unnecessary flag.
> > * gcc.dg/pointer-array-quals-2.c: Remove unnecessary flag.
> >
> >
> > diff --git a/gcc/c/c-typeck.c b/gcc/c/c-typeck.c
> > index fc64ef96fb8..5b13656c090 100644
> > --- a/gcc/c/c-typeck.c
> > +++ b/gcc/c/c-typeck.c
> > @@ -1328,8 +1328,8 @@ comp_target_types (location_t location, tree ttl,
> > tree ttr)
> > val = comptypes_check_enum_int (mvl, mvr, &enum_and_int_p);
> >
> > if (val == 1 && val_ped != 1)
> > - pedwarn (location, OPT_Wpedantic, "pointers to arrays with different
> > qualifiers "
> > - "are incompatible in ISO C");
> > + pedwarn_c11 (location, OPT_Wpedantic, "invalid use of pointers to
> > arrays with different
> > qualifiers "
> > + "in ISO C before C2X");
> >
> > if (val == 2)
> > pedwarn (location, OPT_Wpedantic, "types are not quite compatible");
> > @@ -5396,39 +5396,40 @@ build_conditional_expr (location_t colon_loc, tree
> > ifexp, bool
> > ifexp_bcp,
> > "used in conditional expression");
> > return error_mark_node;
> > }
> > - else if (VOID_TYPE_P (TREE_TYPE (type1))
> > - && !TYPE_ATOMIC (TREE_TYPE (type1)))
> > - {
> > - if ((TREE_CODE (TREE_TYPE (type2)) == ARRAY_TYPE)
> > - && (TYPE_QUALS (strip_array_types (TREE_TYPE (type2)))
> > - & ~TYPE_QUALS (TREE_TYPE (type1))))
> > - warning_at (colon_loc, OPT_Wdiscarded_array_qualifiers,
> > - "pointer to array loses qualifier "
> > - "in conditional expression");
> > -
> > - if (TREE_CODE (TREE_TYPE (type2)) == FUNCTION_TYPE)
> > + else if ((VOID_TYPE_P (TREE_TYPE (type1))
> > + && !TYPE_ATOMIC (TREE_TYPE (type1)))
> > + || (VOID_TYPE_P (TREE_TYPE (type2))
> > + && !TYPE_ATOMIC (TREE_TYPE (type2))))
> > + {
> > + tree t1 = TREE_TYPE (type1);
> > + tree t2 = TREE_TYPE (type2);
> > + if (!VOID_TYPE_P (t1))
> > + {
> > + /* roles are swapped */
> > + t1 = t2;
> > + t2 = TREE_TYPE (type1);
> > + }
> > + tree t2_stripped = strip_array_types (t2);
> > + if ((TREE_CODE (t2) == ARRAY_TYPE)
> > + && (TYPE_QUALS (t2_stripped) & ~TYPE_QUALS (t1)))
> > + {
> > + if (!flag_isoc2x)
> > + warning_at (colon_loc, OPT_Wdiscarded_array_qualifiers,
> > + "pointer to array loses qualifier "
> > + "in conditional expression");
> > + else if (warn_c11_c2x_compat > 0)
> > + warning_at (colon_loc, OPT_Wc11_c2x_compat,
> > + "pointer to array loses qualifier "
> > + "in conditional expression in ISO C before C2X");
> > + }
> > + if (TREE_CODE (t2) == FUNCTION_TYPE)
> > pedwarn (colon_loc, OPT_Wpedantic,
> > "ISO C forbids conditional expr between "
> > "%<void *%> and function pointer");
> > - result_type = build_pointer_type (qualify_type (TREE_TYPE (type1),
> > - TREE_TYPE (type2)));
> > - }
> > - else if (VOID_TYPE_P (TREE_TYPE (type2))
> > - && !TYPE_ATOMIC (TREE_TYPE (type2)))
> > - {
> > - if ((TREE_CODE (TREE_TYPE (type1)) == ARRAY_TYPE)
> > - && (TYPE_QUALS (strip_array_types (TREE_TYPE (type1)))
> > - & ~TYPE_QUALS (TREE_TYPE (type2))))
> > - warning_at (colon_loc, OPT_Wdiscarded_array_qualifiers,
> > - "pointer to array loses qualifier "
> > - "in conditional expression");
> > -
> > - if (TREE_CODE (TREE_TYPE (type1)) == FUNCTION_TYPE)
> > - pedwarn (colon_loc, OPT_Wpedantic,
> > - "ISO C forbids conditional expr between "
> > - "%<void *%> and function pointer");
> > - result_type = build_pointer_type (qualify_type (TREE_TYPE (type2),
> > - TREE_TYPE (type1)));
> > + /* for array, use qualifiers of element type */
> > + if (flag_isoc2x)
> > + t2 = t2_stripped;
> > + result_type = build_pointer_type (qualify_type (t1, t2));
> > }
> > /* Objective-C pointer comparisons are a bit more lenient. */
> > else if (objc_have_common_type (type1, type2, -3, NULL_TREE))
> > @@ -6786,27 +6787,40 @@ convert_for_assignment (location_t location,
> > location_t expr_loc, tree
> > type,
> >
> > /* This macro is used to emit diagnostics to ensure that all format
> > strings are complete sentences, visible to gettext and checked at
> > - compile time. It is the same as PEDWARN_FOR_ASSIGNMENT but with an
> > - extra parameter to enumerate qualifiers. */
> > -#define PEDWARN_FOR_QUALIFIERS(LOCATION, PLOC, OPT, AR, AS, IN, RE, QUALS)
> > \
> > + compile time. It can be called with 'pedwarn' or 'warning_at'. */
> > +#define WARNING_FOR_QUALIFIERS(PEDWARN, LOCATION, PLOC, OPT, AR, AS, IN,
> > RE, QUALS) \
> > do { \
> > switch (errtype) \
> > { \
> > case ic_argpass: \
> > - { \
> > - auto_diagnostic_group d;
> > \
> > - if (pedwarn (PLOC, OPT, AR, parmnum, rname, QUALS)) \
> > - inform_for_arg (fundecl, (PLOC), parmnum, type, rhstype); \
> > - } \
> > + { \
> > + auto_diagnostic_group d; \
> > + if (PEDWARN) { \
> > + if (pedwarn (PLOC, OPT, AR, parmnum, rname, QUALS)) \
> > + inform_for_arg (fundecl, (PLOC), parmnum, type, rhstype); \
> > + } else { \
> > + if (warning_at (PLOC, OPT, AR, parmnum, rname, QUALS)) \
> > + inform_for_arg (fundecl, (PLOC), parmnum, type, rhstype); \
> > + } \
> > + } \
> > break; \
> > case ic_assign: \
> > - pedwarn (LOCATION, OPT, AS, QUALS);
> > \
> > + if (PEDWARN) \
> > + pedwarn (LOCATION, OPT, AS, QUALS); \
> > + else \
> > + warning_at (LOCATION, OPT, AS, QUALS); \
> > break; \
> > case ic_init: \
> > - pedwarn (LOCATION, OPT, IN, QUALS);
> > \
> > + if (PEDWARN) \
> > + pedwarn (LOCATION, OPT, IN, QUALS); \
> > + else \
> > + warning_at (LOCATION, OPT, IN, QUALS); \
> > break; \
> > case ic_return: \
> > - pedwarn (LOCATION, OPT, RE, QUALS);
> > \
> > + if (PEDWARN) \
> > + pedwarn (LOCATION, OPT, RE, QUALS); \
> > + else \
> > + warning_at (LOCATION, OPT, RE, QUALS); \
> > break; \
> > default: \
> > gcc_unreachable (); \
> > @@ -6815,32 +6829,11 @@ convert_for_assignment (location_t location,
> > location_t expr_loc, tree
> > type,
> >
> > /* This macro is used to emit diagnostics to ensure that all format
> > strings are complete sentences, visible to gettext and checked at
> > - compile time. It is the same as PEDWARN_FOR_QUALIFIERS but uses
> > - warning_at instead of pedwarn. */
> > -#define WARNING_FOR_QUALIFIERS(LOCATION, PLOC, OPT, AR, AS, IN, RE, QUALS)
> > \
> > - do { \
> > - switch (errtype) \
> > - { \
> > - case ic_argpass: \
> > - { \
> > - auto_diagnostic_group d;
> > \
> > - if (warning_at (PLOC, OPT, AR, parmnum, rname, QUALS)) \
> > - inform_for_arg (fundecl, (PLOC), parmnum, type, rhstype); \
> > - } \
> > - break; \
> > - case ic_assign: \
> > - warning_at (LOCATION, OPT, AS, QUALS); \
> > - break; \
> > - case ic_init: \
> > - warning_at (LOCATION, OPT, IN, QUALS); \
> > - break; \
> > - case ic_return: \
> > - warning_at (LOCATION, OPT, RE, QUALS); \
> > - break; \
> > - default: \
> > - gcc_unreachable (); \
> > - } \
> > - } while (0)
> > + compile time. It is the same as PEDWARN_FOR_ASSIGNMENT but with an
> > + extra parameter to enumerate qualifiers. */
> > +#define PEDWARN_FOR_QUALIFIERS(LOCATION, PLOC, OPT, AR, AS, IN, RE, QUALS)
> > \
> > + WARNING_FOR_QUALIFIERS (true, LOCATION, PLOC, OPT, AR, AS, IN, RE,
> > QUALS)
> > +
> >
> > if (TREE_CODE (rhs) == EXCESS_PRECISION_EXPR)
> > rhs = TREE_OPERAND (rhs, 0);
> > @@ -7348,17 +7341,18 @@ convert_for_assignment (location_t location,
> > location_t expr_loc, tree
> > type,
> >
> > if (TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC (ttr)
> > & ~TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC (ttl))
> > - WARNING_FOR_QUALIFIERS (location, expr_loc,
> > - OPT_Wdiscarded_array_qualifiers,
> > - G_("passing argument %d of %qE discards
> > "
> > + WARNING_FOR_QUALIFIERS (flag_isoc2x,
> > + location, expr_loc,
> > + OPT_Wdiscarded_array_qualifiers,
> > + G_("passing argument %d of %qE discards
> > "
> > "%qv qualifier from pointer target
> > type"),
> > - G_("assignment discards %qv qualifier "
> > + G_("assignment discards %qv qualifier "
> > "from pointer target type"),
> > - G_("initialization discards %qv
> > qualifier "
> > + G_("initialization discards %qv
> > qualifier "
> > "from pointer target type"),
> > - G_("return discards %qv qualifier from "
> > + G_("return discards %qv qualifier from "
> > "pointer target type"),
> > - TYPE_QUALS (ttr) & ~TYPE_QUALS
> > (ttl));
> > + TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl));
> > }
> > else if (pedantic
> > && ((VOID_TYPE_P (ttl) && TREE_CODE (ttr) == FUNCTION_TYPE)
> > @@ -7381,28 +7375,31 @@ convert_for_assignment (location_t location,
> > location_t expr_loc, tree
> > type,
> > else if (TREE_CODE (ttr) != FUNCTION_TYPE
> > && TREE_CODE (ttl) != FUNCTION_TYPE)
> > {
> > + /* Assignments between atomic and non-atomic objects are OK. */
> > + bool warn_quals_ped = TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC (ttr)
> > + & ~TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC
> > (ttl);
> > + bool warn_quals = TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC (ttr)
> > + & ~TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC
> > (strip_array_types (ttl));
> > +
> > /* Don't warn about loss of qualifier for conversions from
> > qualified void* to pointers to arrays with corresponding
> > - qualifier on the element type. */
> > - if (!pedantic)
> > - ttl = strip_array_types (ttl);
> > + qualifier on the element type (except for pedantic before
> > C23). */
> > + if (warn_quals || (warn_quals_ped && pedantic && !flag_isoc2x))
> > + PEDWARN_FOR_QUALIFIERS (location, expr_loc,
> > + OPT_Wdiscarded_qualifiers,
> > + G_("passing argument %d of %qE discards
> > "
> > + "%qv qualifier from pointer target
> > type"),
> > + G_("assignment discards %qv qualifier "
> > + "from pointer target type"),
> > + G_("initialization discards %qv
> > qualifier "
> > + "from pointer target type"),
> > + G_("return discards %qv qualifier from "
> > + "pointer target type"),
> > + TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl));
> > + else if (warn_quals_ped)
> > + pedwarn_c11 (location, OPT_Wc11_c2x_compat,
> > + "array with qualifier on the element is not
> > qualified before C2X");
> >
> > - /* Assignments between atomic and non-atomic objects are OK. */
> > - if (TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC (ttr)
> > - & ~TYPE_QUALS_NO_ADDR_SPACE_NO_ATOMIC (ttl))
> > - {
> > - PEDWARN_FOR_QUALIFIERS (location, expr_loc,
> > - OPT_Wdiscarded_qualifiers,
> > - G_("passing argument %d of %qE
> > discards "
> > - "%qv qualifier from pointer target
> > type"),
> > - G_("assignment discards %qv qualifier
> > "
> > - "from pointer target type"),
> > - G_("initialization discards %qv
> > qualifier "
> > - "from pointer target type"),
> > - G_("return discards %qv qualifier
> > from "
> > - "pointer target type"),
> > - TYPE_QUALS (ttr) & ~TYPE_QUALS (ttl));
> > - }
> > /* If this is not a case of ignoring a mismatch in signedness,
> > no warning. */
> > else if (VOID_TYPE_P (ttl) || VOID_TYPE_P (ttr)
> > diff --git a/gcc/testsuite/gcc.dg/c11-qual-1.c
> > b/gcc/testsuite/gcc.dg/c11-qual-1.c
> > new file mode 100644
> > index 00000000000..f731e068830
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/c11-qual-1.c
> > @@ -0,0 +1,11 @@
> > +/* Test that qualifiers are lost in tertiary operator for pointers to
> > arrays before C2X,
> > PR98397
> > */
> > +/* { dg-do compile } */
> > +/* { dg-options "-std=c11 -pedantic-errors
> > -Wno-discarded-array-qualifiers" } */
> > +
> > +void foo(void)
> > +{
> > + const int (*u)[1];
> > + void *v;
> > + _Static_assert(_Generic(1 ? u : v, const void*: 0, void*: 1),
> > "qualifier not lost");
> > + _Static_assert(_Generic(1 ? v : u, const void*: 0, void*: 1),
> > "qualifier not lost");
> > +}
> > diff --git a/gcc/testsuite/gcc.dg/c2x-qual-1.c
> > b/gcc/testsuite/gcc.dg/c2x-qual-1.c
> > new file mode 100644
> > index 00000000000..4d33db1907d
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/c2x-qual-1.c
> > @@ -0,0 +1,30 @@
> > +/* Tests related to qualifiers and pointers to arrays in C2X, PR98397 */
> > +/* { dg-do compile } */
> > +/* { dg-options "-std=c2x -pedantic-errors" } */
> > +
> > +/* test that qualifiers are preserved in tertiary operator for pointers to
> > arrays in C2X */
> > +
> > +void f(void)
> > +{
> > + const int (*u)[1];
> > + void *v;
> > + _Static_assert(_Generic(1 ? u : v, const void*: 1, void*: 0), "lost
> > qualifier");
> > + _Static_assert(_Generic(1 ? v : u, const void*: 1, void*: 0), "lost
> > qualifier");
> > +}
> > +
> > +/* test that assignment of unqualified to qualified pointers works as
> > expected */
> > +
> > +void g(void)
> > +{
> > + int (*x)[3];
> > + const int (*p)[3] = x;
> > +}
> > +
> > +/* test that assignment of qualified void pointers works as expected */
> > +
> > +void h(void)
> > +{
> > + const void* x;
> > + const int (*p)[3] = x;
> > +}
> > +
> > diff --git a/gcc/testsuite/gcc.dg/c2x-qual-2.c
> > b/gcc/testsuite/gcc.dg/c2x-qual-2.c
> > new file mode 100644
> > index 00000000000..f60a5b18faa
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/c2x-qual-2.c
> > @@ -0,0 +1,30 @@
> > +/* Tests related to qualifiers and pointers to arrays in C2X, PR98397 */
> > +/* { dg-do compile } */
> > +/* { dg-options "-std=c2x -Wc11-c2x-compat" } */
> > +
> > +/* test that qualifiers are preserved in tertiary operator for pointers to
> > arrays in C2X */
> > +
> > +void f(void)
> > +{
> > + const int (*u)[1];
> > + void *v;
> > + _Static_assert(_Generic(1 ? u : v, const void*: 1, void*: 0), "lost
> > qualifier"); /* { dg-
> > warning "pointer to array loses qualifier in conditional" } */
> > + _Static_assert(_Generic(1 ? v : u, const void*: 1, void*: 0), "lost
> > qualifier"); /* { dg-
> > warning "pointer to array loses qualifier in conditional" } */
> > +}
> > +
> > +/* test that assignment of unqualified to qualified pointers works as
> > expected */
> > +
> > +void g(void)
> > +{
> > + int (*x)[3];
> > + const int (*p)[3] = x; /* { dg-warning "arrays with different
> > qualifiers" } */
> > +}
> > +
> > +/* test that assignment of qualified void pointers works as expected */
> > +
> > +void h(void)
> > +{
> > + const void* x;
> > + const int (*p)[3] = x; /* { dg-warning "array with qualifier on the
> > element is not qualified
> > before C2X" } */
> > +}
> > +
> > diff --git a/gcc/testsuite/gcc.dg/c2x-qual-3.c
> > b/gcc/testsuite/gcc.dg/c2x-qual-3.c
> > new file mode 100644
> > index 00000000000..31896fcb1a1
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/c2x-qual-3.c
> > @@ -0,0 +1,30 @@
> > +/* Tests related to qualifiers and pointers to arrays in C2X, PR98397 */
> > +/* { dg-do compile } */
> > +/* { dg-options "-std=c2x -Wc11-c2x-compat -pedantic-errors" } */
> > +
> > +/* test that qualifiers are preserved in tertiary operator for pointers to
> > arrays in C2X */
> > +
> > +void f(void)
> > +{
> > + const int (*u)[1];
> > + void *v;
> > + _Static_assert(_Generic(1 ? u : v, const void*: 1, void*: 0), "lost
> > qualifier"); /* { dg-
> > warning "pointer to array loses qualifier in conditional" } */
> > + _Static_assert(_Generic(1 ? v : u, const void*: 1, void*: 0), "lost
> > qualifier"); /* { dg-
> > warning "pointer to array loses qualifier in conditional" } */
> > +}
> > +
> > +/* test that assignment of unqualified to qualified pointers works as
> > expected */
> > +
> > +void g(void)
> > +{
> > + int (*x)[3];
> > + const int (*p)[3] = x; /* { dg-warning "arrays with different
> > qualifiers" } */
> > +}
> > +
> > +/* test that assignment of qualified void pointers works as expected */
> > +
> > +void h(void)
> > +{
> > + const void* x;
> > + const int (*p)[3] = x; /* { dg-warning "array with qualifier on the
> > element is not qualified
> > before C2X" } */
> > +}
> > +
> > diff --git a/gcc/testsuite/gcc.dg/c2x-qual-4.c
> > b/gcc/testsuite/gcc.dg/c2x-qual-4.c
> > new file mode 100644
> > index 00000000000..93b4723dcd6
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/c2x-qual-4.c
> > @@ -0,0 +1,105 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-std=c2x" } */
> > +void tvoid(void* x);
> > +void transpose0(double* out, const double* in) { }
> > +void transpose1(double out[2][2], const double in[2][2]) { }
> > +void transpose2(double out[2][2][2], const double in[2][2][2]) { }
> > +// return
> > +int (*y2(const int x[3][3]))[3] { return x; } /* { dg-warning "return
> > discards 'const'
> > qualifier
> > from pointer target type" } */
> > +const int (*y3(int x[3][3]))[3] { return x; }
> > +void test(void)
> > +{
> > + double x0[2];
> > + double y0[2];
> > + const double z0[4];
> > + double x1[2][2];
> > + double y1[2][2];
> > + double o1[2][3];
> > + const double z1[2][2];
> > + double x2[2][2][2];
> > + double y2[2][2][2];
> > + double o2[2][2][3];
> > + const double z2[2][2][2];
> > + // void pointers
> > + tvoid(x0);
> > + tvoid(x1);
> > + tvoid(x2);
> > + tvoid(z0); /* { dg-warning "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + tvoid(z1); /* { dg-warning "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + tvoid(z2); /* { dg-warning "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + void* p;
> > + const void* pc;
> > + p = x0;
> > + p = x1;
> > + p = x2;
> > + p = z0; /* { dg-warning "assignment discards 'const' qualifier from
> > pointer target type" }
> > */
> > + p = z1; /* { dg-warning "assignment discards 'const' qualifier from
> > pointer target type" }
> > */
> > + p = z2; /* { dg-warning "assignment discards 'const' qualifier from
> > pointer target type" }
> > */
> > + pc = x0;
> > + pc = x1;
> > + pc = x2;
> > + pc = z0;
> > + pc = z1;
> > + pc = z2;
> > + transpose0(pc, p); /* { dg-warning "passing argument 1 of 'transpose0'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose1(pc, p); /* { dg-warning "passing argument 1 of 'transpose1'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose2(pc, p); /* { dg-warning "passing argument 1 of 'transpose2'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose0(p, pc);
> > + transpose1(p, pc);
> > + transpose2(p, pc);
> > + // passing as arguments
> > + transpose0(y0, x0);
> > + transpose1(y1, x1);
> > + transpose2(y2, x2);
> > + // initialization
> > + const double (*u0p) = x0;
> > + const double (*u1p)[2] = x1;
> > + const double (*u2p)[2][2] = x2;
> > + double (*v0p) = z0; /* { dg-warning "initialization discards 'const'
> > qualifier from pointer
> > target type" } */
> > + double (*v1p)[2] = z1; /* { dg-warning "initialization discards 'const'
> > qualifier from
> > pointer target type" } */
> > + double (*v2p)[2][2] = z2; /* { dg-warning "initialization discards
> > 'const' qualifier from
> > pointer target type" } */
> > + // subtraction
> > + &(x0[1]) - &(z0[0]);
> > + &(x1[1]) - &(z1[0]);
> > + &(x2[1]) - &(z2[0]);
> > + // comparison
> > + x0 == z0;
> > + x1 == z1;
> > + x2 == z2;
> > + x0 < z0;
> > + x1 < z1;
> > + x2 < z2;
> > + x0 > z0;
> > + x1 > z1;
> > + x2 > z2;
> > + // assignment
> > + u0p = x0;
> > + u1p = x1;
> > + u2p = x2;
> > + v0p = z0; /* { dg-warning "assignment discards 'const' qualifier from
> > pointer target type" }
> > */
> > + v1p = z1; /* { dg-warning "assignment discards 'const' qualifier from
> > pointer target type" }
> > */
> > + v2p = z2; /* { dg-warning "assignment discards 'const' qualifier from
> > pointer target type" }
> > */
> > + // conditional expressions
> > + (void)(1 ? x0 : z0);
> > + (void)(1 ? x1 : z1);
> > + (void)(1 ? x2 : z2);
> > + (void)(1 ? x0 : x1); /* { dg-warning "pointer type mismatch in
> > conditional expression" } */
> > + (void)(1 ? x1 : x2); /* { dg-warning "pointer type mismatch in
> > conditional expression" } */
> > + (void)(1 ? x2 : x0); /* { dg-warning "pointer type mismatch in
> > conditional expression" } */
> > + v0p = (1 ? z0 : v0p); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? z1 : v1p); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v2p = (1 ? z2 : v2p); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v0p = (1 ? x0 : u0p); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? x1 : u1p); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v2p = (1 ? x2 : u2p); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + (1 ? x0 : z0)[0] = 1; /* { dg-error "assignment of read-only location"
> > } */
> > + (1 ? x1 : z1)[0][0] = 1; /* { dg-error "assignment of read-only
> > location" } */
> > + (1 ? x2 : z2)[0][0][0] = 1; /* { dg-error "assignment of read-only
> > location" } */
> > + v0p = (1 ? p : z0); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? p : z1); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v2p = (1 ? p : z2); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v0p = (1 ? pc : x0); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? pc : x1); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v2p = (1 ? pc : x2); /* { dg-warning "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > +}
> > +
> > diff --git a/gcc/testsuite/gcc.dg/c2x-qual-5.c
> > b/gcc/testsuite/gcc.dg/c2x-qual-5.c
> > new file mode 100644
> > index 00000000000..0801fa0eed5
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/c2x-qual-5.c
> > @@ -0,0 +1,101 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-std=c2x -pedantic-errors" } */
> > +void tvoid(void* x);
> > +void transpose0(double* out, const double* in) { }
> > +void transpose1(double out[2][2], const double in[2][2]) { }
> > +void transpose2(double out[2][2][2], const double in[2][2][2]) { }
> > +// return
> > +int (*x2(const int x[3][3]))[3] { return x; } /* { dg-error "return
> > discards" } */
> > +const int (*x3(int x[3][3]))[3] { return x; }
> > +void test(void)
> > +{
> > + double x0[2];
> > + double y0[2];
> > + const double z0[4];
> > + double x1[2][2];
> > + double y1[2][2];
> > + double o1[2][3];
> > + const double z1[2][2];
> > + double x2[2][2][2];
> > + double y2[2][2][2];
> > + double o2[2][2][3];
> > + const double z2[2][2][2];
> > + // void pointers
> > + tvoid(z0); /* { dg-error "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + tvoid(z1); /* { dg-error "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + tvoid(z2); /* { dg-error "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + void* p;
> > + const void* pc;
> > + p = x0;
> > + p = x1;
> > + p = x2;
> > + p = z0; /* { dg-error "assignment discards 'const' qualifier from
> > pointer target type" } */
> > + p = z1; /* { dg-error "assignment discards 'const' qualifier from
> > pointer target type" } */
> > + p = z2; /* { dg-error "assignment discards 'const' qualifier from
> > pointer target type" } */
> > + pc = x0;
> > + pc = x1;
> > + pc = x2;
> > + pc = z0;
> > + pc = z1;
> > + pc = z2;
> > + transpose0(pc, p); /* { dg-error "passing argument 1 of 'transpose0'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose1(pc, p); /* { dg-error "passing argument 1 of 'transpose1'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose2(pc, p); /* { dg-error "passing argument 1 of 'transpose2'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose0(p, pc);
> > + transpose1(p, pc);
> > + transpose2(p, pc);
> > + // passing as arguments
> > + transpose0(y0, x0);
> > + transpose1(y1, o1); /* { dg-error "passing argument 2 of 'transpose1'
> > from incompatible
> > pointer type" } */
> > + transpose1(y1, x1);
> > + transpose2(y2, o2); /* { dg-error "passing argument 2 of 'transpose2'
> > from incompatible
> > pointer type" } */
> > + transpose2(y2, x2);
> > + // initialization
> > + const double (*x0p) = x0;
> > + const double (*x1p)[2] = x1;
> > + const double (*x2p)[2][2] = x2;
> > + double (*v0p) = z0; /* { dg-error "initialization discards 'const'
> > qualifier from pointer
> > target type" } */
> > + double (*v1p)[2] = z1; /* { dg-error "initialization discards" } */
> > + double (*v2p)[2][2] = z2; /* { dg-error "initialization discards" } */
> > + // assignment
> > + x0p = x0;
> > + x1p = x1;
> > + x2p = x2;
> > + // subtraction
> > + &(x0[1]) - &(z0[0]);
> > + &(x1[1]) - &(z1[0]);
> > + &(x2[1]) - &(z2[0]);
> > + // comparison
> > + x0 == z0;
> > + x1 == z1;
> > + x2 == z2;
> > + x0 < z0;
> > + x1 < z1;
> > + x2 < z2;
> > + x0 > z0;
> > + x1 > z1;
> > + x2 > z2;
> > + // conditional expressions
> > + (void)(1 ? x0 : z0);
> > + (void)(1 ? x1 : z1);
> > + (void)(1 ? x2 : z2);
> > + (void)(1 ? x0 : x1); /* { dg-error "pointer type mismatch in
> > conditional expression" } */
> > + (void)(1 ? x1 : x2); /* { dg-error "pointer type mismatch in
> > conditional expression" } */
> > + (void)(1 ? x2 : x0); /* { dg-error "pointer type mismatch in
> > conditional expression" } */
> > + v0p = (1 ? z0 : v0p); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? z1 : v1p); /* { dg-error "assignment discards" } */
> > + v2p = (1 ? z2 : v2p); /* { dg-error "assignment discards" } */
> > + v0p = (1 ? x0 : x0p); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? x1 : x1p); /* { dg-error "assignment discards" } */
> > + v2p = (1 ? x2 : x2p); /* { dg-error "assignment discards" } */
> > + (1 ? x0 : z0)[0] = 1; /* { dg-error "assignment of read-only location"
> > } */
> > + (1 ? x1 : z1)[0][0] = 1; /* { dg-error "assignment of read-only
> > location" } */
> > + (1 ? x2 : z2)[0][0][0] = 1; /* { dg-error "assignment of read-only
> > location" } */
> > + v0p = (1 ? p : z0); /* { dg-error "assignment discards 'const'
> > qualifier from pointer target
> > type" } */
> > + v1p = (1 ? p : z1); /* { dg-error "assignment discards 'const'
> > qualifier from pointer target
> > type" } */
> > + v2p = (1 ? p : z2); /* { dg-error "assignment discards 'const'
> > qualifier from pointer target
> > type" } */
> > + v0p = (1 ? pc : x0); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? pc : x1); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v2p = (1 ? pc : x2); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > +}
> > +
> > diff --git a/gcc/testsuite/gcc.dg/c2x-qual-6.c
> > b/gcc/testsuite/gcc.dg/c2x-qual-6.c
> > new file mode 100644
> > index 00000000000..9c91e206e30
> > --- /dev/null
> > +++ b/gcc/testsuite/gcc.dg/c2x-qual-6.c
> > @@ -0,0 +1,114 @@
> > +/* { dg-do compile } */
> > +/* { dg-options "-std=c2x -Wc11-c2x-compat -pedantic-errors" } */
> > +void tvoid(void* x);
> > +void transpose0(double* out, const double* in) { }
> > +void transpose1(double out[2][2], const double in[2][2]) { }
> > +void transpose2(double out[2][2][2], const double in[2][2][2]) { }
> > +// return
> > +int (*x2(const int x[3][3]))[3] { return x; } /* { dg-warning "before C2X"
> > } */
> > + /* { dg-error "return discards"
> > "" { target *-*-* }
> > .-1 } */
> > +const int (*x3(int x[3][3]))[3] { return x; } /* { dg-warning "before
> > C2X" } */
> > +void test(void)
> > +{
> > + double x0[2];
> > + double y0[2];
> > + const double z0[4];
> > + double x1[2][2];
> > + double y1[2][2];
> > + double o1[2][3];
> > + const double z1[2][2];
> > + double x2[2][2][2];
> > + double y2[2][2][2];
> > + double o2[2][2][3];
> > + const double z2[2][2][2];
> > + // void pointers
> > + tvoid(z0); /* { dg-error "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + tvoid(z1); /* { dg-error "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + tvoid(z2); /* { dg-error "passing argument 1 of 'tvoid' discards
> > 'const' qualifier from
> > pointer target type" } */
> > + void* p;
> > + const void* pc;
> > + p = x0;
> > + p = x1;
> > + p = x2;
> > + p = z0; /* { dg-error "assignment discards 'const' qualifier from
> > pointer target type" } */
> > + p = z1; /* { dg-error "assignment discards 'const' qualifier from
> > pointer target type" } */
> > + p = z2; /* { dg-error "assignment discards 'const' qualifier from
> > pointer target type" } */
> > + pc = x0;
> > + pc = x1;
> > + pc = x2;
> > + pc = z0;
> > + pc = z1;
> > + pc = z2;
> > + transpose0(pc, p); /* { dg-error "passing argument 1 of 'transpose0'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose1(pc, p); /* { dg-error "passing argument 1 of 'transpose1'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose2(pc, p); /* { dg-error "passing argument 1 of 'transpose2'
> > discards 'const'
> > qualifier from pointer target type" } */
> > + transpose0(p, pc);
> > + transpose1(p, pc); /* { dg-warning "before C2X" } */
> > + transpose2(p, pc); /* { dg-warning "before C2X" } */
> > + // passing as arguments
> > + transpose0(y0, x0);
> > + transpose1(y1, o1); /* { dg-error "passing argument 2 of 'transpose1'
> > from incompatible
> > pointer type" } */
> > + transpose1(y1, x1); /* { dg-warning "before C2X" } */
> > + transpose2(y2, o2); /* { dg-error "passing argument 2 of 'transpose2'
> > from incompatible
> > pointer type" } */
> > + transpose2(y2, x2); /* { dg-warning "before C2X" } */
> > + // initialization
> > + const double (*x0p) = x0;
> > + const double (*x1p)[2] = x1; /* { dg-warning "before C2X" } */
> > + const double (*x2p)[2][2] = x2; /* { dg-warning "before C2X" } */
> > + double (*v0p) = z0; /* { dg-error "initialization discards 'const'
> > qualifier from pointer
> > target type" } */
> > + double (*v1p)[2] = z1; /* { dg-warning "before C2X" } */
> > + /* { dg-error "initialization discards" "" {
> > target *-*-* } .-1 } */
> > + double (*v2p)[2][2] = z2; /* { dg-warning "before C2X" } */
> > + /* { dg-error "initialization discards" "" {
> > target *-*-* } .-1 } */
> > +
> > + // assignment
> > + x0p = x0;
> > + x1p = x1; /* { dg-warning "before C2X" } */
> > + x2p = x2; /* { dg-warning "before C2X" } */
> > +
> > + // subtraction
> > + &(x0[1]) - &(z0[0]);
> > + &(x1[1]) - &(z1[0]); /* { dg-warning "before C2X" } */
> > + &(x2[1]) - &(z2[0]); /* { dg-warning "before C2X" } */
> > + // comparison
> > + x0 == z0;
> > + x1 == z1; /* { dg-warning "before C2X" } */
> > + x2 == z2; /* { dg-warning "before C2X" } */
> > + x0 < z0;
> > + x1 < z1; /* { dg-warning "before C2X" } */
> > + x2 < z2; /* { dg-warning "before C2X" } */
> > + x0 > z0;
> > + x1 > z1; /* { dg-warning "before C2X" } */
> > + x2 > z2; /* { dg-warning "before C2X" } */
> > + // conditional expressions
> > + (void)(1 ? x0 : z0);
> > + (void)(1 ? x1 : z1); /* { dg-warning "before C2X" } */
> > + (void)(1 ? x2 : z2); /* { dg-warning "before C2X" } */
> > + (void)(1 ? x0 : x1); /* { dg-error "pointer type mismatch in
> > conditional expression" } */
> > + (void)(1 ? x1 : x2); /* { dg-error "pointer type mismatch in
> > conditional expression" } */
> > + (void)(1 ? x2 : x0); /* { dg-error "pointer type mismatch in
> > conditional expression" } */
> > + v0p = (1 ? z0 : v0p); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? z1 : v1p); /* { dg-warning "before C2X" } */
> > + /* { dg-error "assignment discards" "" { target
> > *-*-* } .-1 } */
> > + v2p = (1 ? z2 : v2p); /* { dg-warning "before C2X" } */
> > + /* { dg-error "assignment discards" "" { target
> > *-*-* } .-1 } */
> > + v0p = (1 ? x0 : x0p); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? x1 : x1p); /* { dg-error "assignment discards" } */
> > + /* { dg-warning "before C2X" "" { target *-*-*
> > } .-1 } */
> > + v2p = (1 ? x2 : x2p); /* { dg-error "assignment discards" } */
> > + /* { dg-warning "before C2X" "" { target *-*-*
> > } .-1 } */
> > + (1 ? x0 : z0)[0] = 1; /* { dg-error "assignment of read-only location"
> > } */
> > + (1 ? x1 : z1)[0][0] = 1; /* { dg-error "assignment of read-only
> > location" } */
> > + /* { dg-warning "before C2X" "" { target *-*-*
> > } .-1 } */
> > + (1 ? x2 : z2)[0][0][0] = 1; /* { dg-error "assignment of read-only
> > location" } */
> > + /* { dg-warning "before C2X" "" { target *-*-*
> > } .-1 } */
> > + v0p = (1 ? p : z0); /* { dg-error "assignment discards 'const'
> > qualifier from pointer target
> > type" } */
> > + v1p = (1 ? p : z1); /* { dg-error "assignment discards 'const'
> > qualifier from pointer target
> > type" } */
> > + /* { dg-warning "before C2X" "" { target *-*-*
> > } .-1 } */
> > + v2p = (1 ? p : z2); /* { dg-error "assignment discards 'const'
> > qualifier from pointer target
> > type" } */
> > + /* { dg-warning "before C2X" "" { target *-*-*
> > } .-1 } */
> > + v0p = (1 ? pc : x0); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v1p = (1 ? pc : x1); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > + v2p = (1 ? pc : x2); /* { dg-error "assignment discards 'const'
> > qualifier from pointer
> > target type" } */
> > +}
> > +
> > diff --git a/gcc/testsuite/gcc.dg/pointer-array-quals-1.c
> > b/gcc/testsuite/gcc.dg/pointer-array-
> > quals-1.c
> > index 921a37e9e0d..498ab223162 100644
> > --- a/gcc/testsuite/gcc.dg/pointer-array-quals-1.c
> > +++ b/gcc/testsuite/gcc.dg/pointer-array-quals-1.c
> > @@ -1,6 +1,6 @@
> > /* { dg-do compile } */
> > /* Origin: Martin Uecker <uec...@eecs.berkeley.edu> */
> > -/* { dg-options "-Wdiscarded-array-qualifiers" } */
> > +/* { dg-options "" } */
> > void tvoid(void* x);
> > void transpose0(double* out, const double* in) { }
> > void transpose1(double out[2][2], const double in[2][2]) { }
> > diff --git a/gcc/testsuite/gcc.dg/pointer-array-quals-2.c
> > b/gcc/testsuite/gcc.dg/pointer-array-
> > quals-2.c
> > index 30689c7312d..4c95d8a3a78 100644
> > --- a/gcc/testsuite/gcc.dg/pointer-array-quals-2.c
> > +++ b/gcc/testsuite/gcc.dg/pointer-array-quals-2.c
> > @@ -1,5 +1,5 @@
> > /* { dg-do compile } */
> > -/* { dg-options "-Wdiscarded-array-qualifiers -pedantic-errors" } */
> > +/* { dg-options "-pedantic-errors" } */
> > /* Origin: Martin Uecker <uec...@eecs.berkeley.edu> */
> > void tvoid(void* x);
> > void transpose0(double* out, const double* in) { }
