Siddhesh,
Thanks. I will update the testing case per your change.
Qing
> On Feb 1, 2023, at 11:48 AM, Siddhesh Poyarekar <siddh...@gotplt.org> wrote:
>
> On 2023-01-31 09:11, Qing Zhao wrote:
>> GCC extension accepts the case when a struct with a flexible array member
>> is embedded into another struct (possibly recursively).
>> __builtin_object_size should treat such struct as flexible size per
>> -fstrict-flex-arrays.
>> PR tree-optimization/101832
>> gcc/ChangeLog:
>> PR tree-optimization/101832
>> * tree-object-size.cc (flexible_size_type_p): New function.
>> (addr_object_size): Handle structure/union type when it has
>> flexible size.
>> gcc/testsuite/ChangeLog:
>> PR tree-optimization/101832
>> * gcc.dg/builtin-object-size-pr101832-2.c: New test.
>> * gcc.dg/builtin-object-size-pr101832-3.c: New test.
>> * gcc.dg/builtin-object-size-pr101832-4.c: New test.
>> * gcc.dg/builtin-object-size-pr101832.c: New test.
>> ---
>> .../gcc.dg/builtin-object-size-pr101832-2.c | 135 ++++++++++++++++++
>> .../gcc.dg/builtin-object-size-pr101832-3.c | 135 ++++++++++++++++++
>> .../gcc.dg/builtin-object-size-pr101832-4.c | 135 ++++++++++++++++++
>> .../gcc.dg/builtin-object-size-pr101832.c | 119 +++++++++++++++
>> gcc/tree-object-size.cc | 115 +++++++++++----
>> 5 files changed, 611 insertions(+), 28 deletions(-)
>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>> create mode 100644 gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>> new file mode 100644
>> index 00000000000..f38babc5415
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-2.c
>> @@ -0,0 +1,135 @@
>> +/* PR 101832:
>> + GCC extension accepts the case when a struct with a flexible array member
>> + is embedded into another struct (possibly recursively).
>> + __builtin_object_size will treat such struct as flexible size per
>> + -fstrict-flex-arrays. */
>> +/* { dg-do run } */
>> +/* { dg-options "-O2 -fstrict-flex-arrays=1" } */
>> +
>> +#include <stdio.h>
>> +
>> +unsigned n_fails = 0;
>> +
>> +#define expect(p, _v) do { \
>> + size_t v = _v; \
>> + if (p == v) \
>> + printf("ok: %s == %zd\n", #p, p); \
>> + else {\
>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>> + n_fails++; \
>
> I just pushed my testsuite fix, so you could use the macros in
> gcc.dg/builtin-object-size-common.h instead of accounting this yourself.
>
> Also if you use __builtin_printf, you won't have to include stdio.h.
>
> Thanks,
> Sid
>
>> + } \
>> +} while (0);
>> +
>> +struct A {
>> + int n;
>> + char data[];/* Content following header */
>> +};
>> +
>> +struct B {
>> + int m;
>> + struct A a;
>> +};
>> +
>> +struct C {
>> + int q;
>> + struct B b;
>> +};
>> +
>> +struct A0 {
>> + int n;
>> + char data[0];/* Content following header */
>> +};
>> +
>> +struct B0 {
>> + int m;
>> + struct A0 a;
>> +};
>> +
>> +struct C0 {
>> + int q;
>> + struct B0 b;
>> +};
>> +
>> +struct A1 {
>> + int n;
>> + char data[1];/* Content following header */
>> +};
>> +
>> +struct B1 {
>> + int m;
>> + struct A1 a;
>> +};
>> +
>> +struct C1 {
>> + int q;
>> + struct B1 b;
>> +};
>> +
>> +struct An {
>> + int n;
>> + char data[8];/* Content following header */
>> +};
>> +
>> +struct Bn {
>> + int m;
>> + struct An a;
>> +};
>> +
>> +struct Cn {
>> + int q;
>> + struct Bn b;
>> +};
>> +
>> +volatile void *magic1, *magic2;
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + struct B *outer;
>> + struct C *outest;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer = (void *)magic1;
>> + outest = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer->a, 1), -1);
>> + expect(__builtin_object_size(&outest->b, 1), -1);
>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>> +
>> + struct B0 *outer0;
>> + struct C0 *outest0;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer0 = (void *)magic1;
>> + outest0 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer0->a, 1), -1);
>> + expect(__builtin_object_size(&outest0->b, 1), -1);
>> + expect(__builtin_object_size(&outest0->b.a, 1), -1);
>> +
>> + struct B1 *outer1;
>> + struct C1 *outest1;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer1 = (void *)magic1;
>> + outest1 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer1->a, 1), -1);
>> + expect(__builtin_object_size(&outest1->b, 1), -1);
>> + expect(__builtin_object_size(&outest1->b.a, 1), -1);
>> +
>> + struct Bn *outern;
>> + struct Cn *outestn;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outern = (void *)magic1;
>> + outestn = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a));
>> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b));
>> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a));
>> +
>> + if (n_fails > 0)
>> + __builtin_abort ();
>> +
>> + return 0;
>> +}
>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>> new file mode 100644
>> index 00000000000..aaae99b8d67
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-3.c
>> @@ -0,0 +1,135 @@
>> +/* PR 101832:
>> + GCC extension accepts the case when a struct with a flexible array member
>> + is embedded into another struct (possibly recursively).
>> + __builtin_object_size will treat such struct as flexible size per
>> + -fstrict-flex-arrays. */
>> +/* { dg-do run } */
>> +/* { dg-options "-O2 -fstrict-flex-arrays=2" } */
>> +
>> +#include <stdio.h>
>> +
>> +unsigned n_fails = 0;
>> +
>> +#define expect(p, _v) do { \
>> + size_t v = _v; \
>> + if (p == v) \
>> + printf("ok: %s == %zd\n", #p, p); \
>> + else {\
>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>> + n_fails++; \
>> + } \
>> +} while (0);
>> +
>> +struct A {
>> + int n;
>> + char data[];/* Content following header */
>> +};
>> +
>> +struct B {
>> + int m;
>> + struct A a;
>> +};
>> +
>> +struct C {
>> + int q;
>> + struct B b;
>> +};
>> +
>> +struct A0 {
>> + int n;
>> + char data[0];/* Content following header */
>> +};
>> +
>> +struct B0 {
>> + int m;
>> + struct A0 a;
>> +};
>> +
>> +struct C0 {
>> + int q;
>> + struct B0 b;
>> +};
>> +
>> +struct A1 {
>> + int n;
>> + char data[1];/* Content following header */
>> +};
>> +
>> +struct B1 {
>> + int m;
>> + struct A1 a;
>> +};
>> +
>> +struct C1 {
>> + int q;
>> + struct B1 b;
>> +};
>> +
>> +struct An {
>> + int n;
>> + char data[8];/* Content following header */
>> +};
>> +
>> +struct Bn {
>> + int m;
>> + struct An a;
>> +};
>> +
>> +struct Cn {
>> + int q;
>> + struct Bn b;
>> +};
>> +
>> +volatile void *magic1, *magic2;
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + struct B *outer;
>> + struct C *outest;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer = (void *)magic1;
>> + outest = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer->a, 1), -1);
>> + expect(__builtin_object_size(&outest->b, 1), -1);
>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>> +
>> + struct B0 *outer0;
>> + struct C0 *outest0;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer0 = (void *)magic1;
>> + outest0 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer0->a, 1), -1);
>> + expect(__builtin_object_size(&outest0->b, 1), -1);
>> + expect(__builtin_object_size(&outest0->b.a, 1), -1);
>> +
>> + struct B1 *outer1;
>> + struct C1 *outest1;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer1 = (void *)magic1;
>> + outest1 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer1->a, 1), sizeof(outer1->a));
>> + expect(__builtin_object_size(&outest1->b, 1), sizeof(outest1->b));
>> + expect(__builtin_object_size(&outest1->b.a, 1), sizeof(outest1->b.a));
>> +
>> + struct Bn *outern;
>> + struct Cn *outestn;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outern = (void *)magic1;
>> + outestn = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a));
>> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b));
>> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a));
>> +
>> + if (n_fails > 0)
>> + __builtin_abort ();
>> +
>> + return 0;
>> +}
>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>> new file mode 100644
>> index 00000000000..424264e2acd
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832-4.c
>> @@ -0,0 +1,135 @@
>> +/* PR 101832:
>> + GCC extension accepts the case when a struct with a flexible array member
>> + is embedded into another struct (possibly recursively).
>> + __builtin_object_size will treat such struct as flexible size per
>> + -fstrict-flex-arrays. */
>> +/* { dg-do run } */
>> +/* { dg-options "-O2 -fstrict-flex-arrays=3" } */
>> +
>> +#include <stdio.h>
>> +
>> +unsigned n_fails = 0;
>> +
>> +#define expect(p, _v) do { \
>> + size_t v = _v; \
>> + if (p == v) \
>> + printf("ok: %s == %zd\n", #p, p); \
>> + else {\
>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>> + n_fails++; \
>> + } \
>> +} while (0);
>> +
>> +struct A {
>> + int n;
>> + char data[];/* Content following header */
>> +};
>> +
>> +struct B {
>> + int m;
>> + struct A a;
>> +};
>> +
>> +struct C {
>> + int q;
>> + struct B b;
>> +};
>> +
>> +struct A0 {
>> + int n;
>> + char data[0];/* Content following header */
>> +};
>> +
>> +struct B0 {
>> + int m;
>> + struct A0 a;
>> +};
>> +
>> +struct C0 {
>> + int q;
>> + struct B0 b;
>> +};
>> +
>> +struct A1 {
>> + int n;
>> + char data[1];/* Content following header */
>> +};
>> +
>> +struct B1 {
>> + int m;
>> + struct A1 a;
>> +};
>> +
>> +struct C1 {
>> + int q;
>> + struct B1 b;
>> +};
>> +
>> +struct An {
>> + int n;
>> + char data[8];/* Content following header */
>> +};
>> +
>> +struct Bn {
>> + int m;
>> + struct An a;
>> +};
>> +
>> +struct Cn {
>> + int q;
>> + struct Bn b;
>> +};
>> +
>> +volatile void *magic1, *magic2;
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + struct B *outer;
>> + struct C *outest;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer = (void *)magic1;
>> + outest = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer->a, 1), -1);
>> + expect(__builtin_object_size(&outest->b, 1), -1);
>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>> +
>> + struct B0 *outer0;
>> + struct C0 *outest0;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer0 = (void *)magic1;
>> + outest0 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer0->a, 1), sizeof(outer0->a));
>> + expect(__builtin_object_size(&outest0->b, 1), sizeof(outest0->b));
>> + expect(__builtin_object_size(&outest0->b.a, 1), sizeof(outest0->b.a));
>> +
>> + struct B1 *outer1;
>> + struct C1 *outest1;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outer1 = (void *)magic1;
>> + outest1 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer1->a, 1), sizeof(outer1->a));
>> + expect(__builtin_object_size(&outest1->b, 1), sizeof(outest1->b));
>> + expect(__builtin_object_size(&outest1->b.a, 1), sizeof(outest1->b.a));
>> +
>> + struct Bn *outern;
>> + struct Cn *outestn;
>> +
>> + /* Make sure optimization can't find some other object size. */
>> + outern = (void *)magic1;
>> + outestn = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outern->a, 1), sizeof(outern->a));
>> + expect(__builtin_object_size(&outestn->b, 1), sizeof(outestn->b));
>> + expect(__builtin_object_size(&outestn->b.a, 1), sizeof(outestn->b.a));
>> +
>> + if (n_fails > 0)
>> + __builtin_abort ();
>> +
>> + return 0;
>> +}
>> diff --git a/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>> b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>> new file mode 100644
>> index 00000000000..8ed6980edf0
>> --- /dev/null
>> +++ b/gcc/testsuite/gcc.dg/builtin-object-size-pr101832.c
>> @@ -0,0 +1,119 @@
>> +/* PR 101832:
>> + GCC extension accepts the case when a struct with a flexible array member
>> + is embedded into another struct (possibly recursively).
>> + __builtin_object_size will treat such struct as flexible size per
>> + -fstrict-flex-arrays. */
>> +/* { dg-do run } */
>> +/* { dg-options "-O2" } */
>> +
>> +#include <stdio.h>
>> +
>> +unsigned n_fails = 0;
>> +
>> +#define expect(p, _v) do { \
>> + size_t v = _v; \
>> + if (p == v) \
>> + printf("ok: %s == %zd\n", #p, p); \
>> + else {\
>> + printf("WAT: %s == %zd (expected %zd)\n", #p, p, v); \
>> + n_fails++; \
>> + } \
>> +} while (0);
>> +
>> +struct A {
>> + int n;
>> + char data[];/* Content following header */
>> +};
>> +
>> +struct B {
>> + int m;
>> + struct A a;
>> +};
>> +
>> +struct C {
>> + int q;
>> + struct B b;
>> +};
>> +
>> +struct A0 {
>> + int n;
>> + char data[0];/* Content following header */
>> +};
>> +
>> +struct B0 {
>> + int m;
>> + struct A0 a;
>> +};
>> +
>> +struct C0 {
>> + int q;
>> + struct B0 b;
>> +};
>> +
>> +struct A1 {
>> + int n;
>> + char data[1];/* Content following header */
>> +};
>> +
>> +struct B1 {
>> + int m;
>> + struct A1 a;
>> +};
>> +
>> +struct C1 {
>> + int q;
>> + struct B1 b;
>> +};
>> +
>> +struct An {
>> + int n;
>> + char data[8];/* Content following header */
>> +};
>> +
>> +struct Bn {
>> + int m;
>> + struct An a;
>> +};
>> +
>> +struct Cn {
>> + int q;
>> + struct Bn b;
>> +};
>> +
>> +volatile void *magic1, *magic2;
>> +
>> +int main(int argc, char *argv[])
>> +{
>> + struct B *outer = (void *)magic1;
>> + struct C *outest = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer->a, 1), -1);
>> + expect(__builtin_object_size(&outest->b, 1), -1);
>> + expect(__builtin_object_size(&outest->b.a, 1), -1);
>> +
>> + struct B0 *outer0 = (void *)magic1;
>> + struct C0 *outest0 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer0->a, 1), -1);
>> + expect(__builtin_object_size(&outest0->b, 1), -1);
>> + expect(__builtin_object_size(&outest0->b.a, 1), -1);
>> +
>> + struct B1 *outer1 = (void *)magic1;
>> + struct C1 *outest1 = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outer1->a, 1), -1);
>> + expect(__builtin_object_size(&outest1->b, 1), -1);
>> + expect(__builtin_object_size(&outest1->b.a, 1), -1);
>> +
>> + struct Bn *outern = (void *)magic1;
>> + struct Cn *outestn = (void *)magic2;
>> +
>> + expect(__builtin_object_size(&outern->a, 1), -1);
>> + expect(__builtin_object_size(&outestn->b, 1), -1);
>> + expect(__builtin_object_size(&outestn->b.a, 1), -1);
>> +
>> + if (n_fails > 0)
>> + __builtin_abort ();
>> +
>> + return 0;
>> +}
>> diff --git a/gcc/tree-object-size.cc b/gcc/tree-object-size.cc
>> index 9a936a91983..56b78ca2a8c 100644
>> --- a/gcc/tree-object-size.cc
>> +++ b/gcc/tree-object-size.cc
>> @@ -500,6 +500,42 @@ decl_init_size (tree decl, bool min)
>> return size;
>> }
>> +/* Determine whether TYPE is a structure with a flexible array member
>> + per -fstrict-flex-array or a union containing such a structure
>> + (possibly recursively). */
>> +static bool
>> +flexible_size_type_p (const_tree type)
>> +{
>> + tree x = NULL_TREE;
>> + tree last = NULL_TREE;
>> + switch (TREE_CODE (type))
>> + {
>> + case RECORD_TYPE:
>> + for (x = TYPE_FIELDS (type); x != NULL_TREE; x = DECL_CHAIN (x))
>> + if (TREE_CODE (x) == FIELD_DECL)
>> + last = x;
>> + if (last == NULL_TREE)
>> + return false;
>> + if (TREE_CODE (TREE_TYPE (last)) == ARRAY_TYPE
>> + && !DECL_NOT_FLEXARRAY (last))
>> + return true;
>> + else if (TREE_CODE (TREE_TYPE (last)) == RECORD_TYPE
>> + || TREE_CODE (TREE_TYPE (last)) == UNION_TYPE)
>> + return flexible_size_type_p (TREE_TYPE (last));
>> + return false;
>> + case UNION_TYPE:
>> + for (x = TYPE_FIELDS (type); x != NULL_TREE; x = DECL_CHAIN (x))
>> + {
>> + if (TREE_CODE (x) == FIELD_DECL
>> + && flexible_array_type_p (TREE_TYPE (x)))
>> + return true;
>> + }
>> + return false;
>> + default:
>> + return false;
>> + }
>> +}
>> +
>> /* Compute __builtin_object_size for PTR, which is a ADDR_EXPR.
>> OBJECT_SIZE_TYPE is the second argument from __builtin_object_size.
>> If unknown, return size_unknown (object_size_type). */
>> @@ -633,45 +669,68 @@ addr_object_size (struct object_size_info *osi,
>> const_tree ptr,
>> v = NULL_TREE;
>> break;
>> case COMPONENT_REF:
>> - if (TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE)
>> + /* When the ref is not to an array, a record or a union, it
>> + will not have flexible size, compute the object size
>> + directly. */
>> + if ((TREE_CODE (TREE_TYPE (v)) != ARRAY_TYPE)
>> + && (TREE_CODE (TREE_TYPE (v)) != RECORD_TYPE)
>> + && (TREE_CODE (TREE_TYPE (v)) != UNION_TYPE))
>> {
>> v = NULL_TREE;
>> break;
>> }
>> - is_flexible_array_mem_ref = array_ref_flexible_size_p (v);
>> - while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>> - if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> - != UNION_TYPE
>> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> - != QUAL_UNION_TYPE)
>> - break;
>> - else
>> - v = TREE_OPERAND (v, 0);
>> - if (TREE_CODE (v) == COMPONENT_REF
>> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> - == RECORD_TYPE)
>> + /* if the record or union does not have flexible size
>> + compute the object size directly. */
>> + if (TREE_CODE (TREE_TYPE (v)) == RECORD_TYPE
>> + || TREE_CODE (TREE_TYPE (v)) == UNION_TYPE)
>> {
>> - /* compute object size only if v is not a
>> - flexible array member. */
>> - if (!is_flexible_array_mem_ref)
>> + if (!flexible_size_type_p (TREE_TYPE (v)))
>> {
>> v = NULL_TREE;
>> break;
>> }
>> - v = TREE_OPERAND (v, 0);
>> + else
>> + v = TREE_OPERAND (v, 0);
>> }
>> - while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>> - if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> - != UNION_TYPE
>> - && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> - != QUAL_UNION_TYPE)
>> - break;
>> - else
>> - v = TREE_OPERAND (v, 0);
>> - if (v != pt_var)
>> - v = NULL_TREE;
>> else
>> - v = pt_var;
>> + {
>> + /* Now the ref is to an array type. */
>> + is_flexible_array_mem_ref
>> + = array_ref_flexible_size_p (v);
>> + while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>> + if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> + != UNION_TYPE
>> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> + != QUAL_UNION_TYPE)
>> + break;
>> + else
>> + v = TREE_OPERAND (v, 0);
>> + if (TREE_CODE (v) == COMPONENT_REF
>> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> + == RECORD_TYPE)
>> + {
>> + /* compute object size only if v is not a
>> + flexible array member. */
>> + if (!is_flexible_array_mem_ref)
>> + {
>> + v = NULL_TREE;
>> + break;
>> + }
>> + v = TREE_OPERAND (v, 0);
>> + }
>> + while (v != pt_var && TREE_CODE (v) == COMPONENT_REF)
>> + if (TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> + != UNION_TYPE
>> + && TREE_CODE (TREE_TYPE (TREE_OPERAND (v, 0)))
>> + != QUAL_UNION_TYPE)
>> + break;
>> + else
>> + v = TREE_OPERAND (v, 0);
>> + if (v != pt_var)
>> + v = NULL_TREE;
>> + else
>> + v = pt_var;
>> + }
>> break;
>> default:
>> v = pt_var;
