[5/8] Dump the list of merged alias pairs

This patch dumps the final (merged) list of alias pairs.  It also adds:

- WAW and RAW versions of vect-alias-check-8.c
- a "well-ordered" version of vect-alias-check-9.c (i.e. all reads
  before any writes)
- a test with mixed steps in the same alias pair

I also tweaked the test value in vect-alias-check-9.c so that the result
was less likely to be accidentally correct if the alias isn't honoured.


2019-11-11  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* tree-data-ref.c (dump_alias_pair): New function.
	(prune_runtime_alias_test_list): Use it to dump each merged alias pair.

gcc/testsuite/
	* gcc.dg/vect/vect-alias-check-8.c: Test for the RAW flag.
	* gcc.dg/vect/vect-alias-check-9.c: Test for the ARBITRARY flag.
	(TEST_VALUE): Use a higher value for early iterations.
	* gcc.dg/vect/vect-alias-check-14.c: New test.
	* gcc.dg/vect/vect-alias-check-15.c: Likewise.
	* gcc.dg/vect/vect-alias-check-16.c: Likewise.
	* gcc.dg/vect/vect-alias-check-17.c: Likewise.

On Mon, Nov 11, 2019 at 7:49 PM Richard Sandiford
<richard.sandiford@arm.com> wrote:
>
> This patch dumps the final (merged) list of alias pairs.  It also adds:
>
> - WAW and RAW versions of vect-alias-check-8.c
> - a "well-ordered" version of vect-alias-check-9.c (i.e. all reads
>   before any writes)
> - a test with mixed steps in the same alias pair
>
> I also tweaked the test value in vect-alias-check-9.c so that the result
> was less likely to be accidentally correct if the alias isn't honoured.

OK.

>
> 2019-11-11  Richard Sandiford  <richard.sandiford@arm.com>
>
> gcc/
>         * tree-data-ref.c (dump_alias_pair): New function.
>         (prune_runtime_alias_test_list): Use it to dump each merged alias pair.
>
> gcc/testsuite/
>         * gcc.dg/vect/vect-alias-check-8.c: Test for the RAW flag.
>         * gcc.dg/vect/vect-alias-check-9.c: Test for the ARBITRARY flag.
>         (TEST_VALUE): Use a higher value for early iterations.
>         * gcc.dg/vect/vect-alias-check-14.c: New test.
>         * gcc.dg/vect/vect-alias-check-15.c: Likewise.
>         * gcc.dg/vect/vect-alias-check-16.c: Likewise.
>         * gcc.dg/vect/vect-alias-check-17.c: Likewise.
>
> Index: gcc/tree-data-ref.c
> ===================================================================
> --- gcc/tree-data-ref.c 2019-11-11 18:30:53.863170161 +0000
> +++ gcc/tree-data-ref.c 2019-11-11 18:30:57.167147102 +0000
> @@ -1453,6 +1453,54 @@ comp_dr_with_seg_len_pair (const void *p
>    return 0;
>  }
>
> +/* Dump information about ALIAS_PAIR, indenting each line by INDENT.  */
> +
> +static void
> +dump_alias_pair (dr_with_seg_len_pair_t *alias_pair, const char *indent)
> +{
> +  dump_printf (MSG_NOTE, "%sreference:      %T vs. %T\n", indent,
> +              DR_REF (alias_pair->first.dr),
> +              DR_REF (alias_pair->second.dr));
> +
> +  dump_printf (MSG_NOTE, "%ssegment length: %T", indent,
> +              alias_pair->first.seg_len);
> +  if (!operand_equal_p (alias_pair->first.seg_len,
> +                       alias_pair->second.seg_len, 0))
> +    dump_printf (MSG_NOTE, " vs. %T", alias_pair->second.seg_len);
> +
> +  dump_printf (MSG_NOTE, "\n%saccess size:    ", indent);
> +  dump_dec (MSG_NOTE, alias_pair->first.access_size);
> +  if (maybe_ne (alias_pair->first.access_size, alias_pair->second.access_size))
> +    {
> +      dump_printf (MSG_NOTE, " vs. ");
> +      dump_dec (MSG_NOTE, alias_pair->second.access_size);
> +    }
> +
> +  dump_printf (MSG_NOTE, "\n%salignment:      %d", indent,
> +              alias_pair->first.align);
> +  if (alias_pair->first.align != alias_pair->second.align)
> +    dump_printf (MSG_NOTE, " vs. %d", alias_pair->second.align);
> +
> +  dump_printf (MSG_NOTE, "\n%sflags:         ", indent);
> +  if (alias_pair->flags & DR_ALIAS_RAW)
> +    dump_printf (MSG_NOTE, " RAW");
> +  if (alias_pair->flags & DR_ALIAS_WAR)
> +    dump_printf (MSG_NOTE, " WAR");
> +  if (alias_pair->flags & DR_ALIAS_WAW)
> +    dump_printf (MSG_NOTE, " WAW");
> +  if (alias_pair->flags & DR_ALIAS_ARBITRARY)
> +    dump_printf (MSG_NOTE, " ARBITRARY");
> +  if (alias_pair->flags & DR_ALIAS_SWAPPED)
> +    dump_printf (MSG_NOTE, " SWAPPED");
> +  if (alias_pair->flags & DR_ALIAS_UNSWAPPED)
> +    dump_printf (MSG_NOTE, " UNSWAPPED");
> +  if (alias_pair->flags & DR_ALIAS_MIXED_STEPS)
> +    dump_printf (MSG_NOTE, " MIXED_STEPS");
> +  if (alias_pair->flags == 0)
> +    dump_printf (MSG_NOTE, " <none>");
> +  dump_printf (MSG_NOTE, "\n");
> +}
> +
>  /* Merge alias checks recorded in ALIAS_PAIRS and remove redundant ones.
>     FACTOR is number of iterations that each data reference is accessed.
>
> @@ -1656,6 +1704,8 @@ prune_runtime_alias_test_list (vec<dr_wi
>       dr_with_seg_len_pair_t.  If we ended up combining swapped and
>       unswapped pairs into the same check, we have to invalidate any
>       RAW, WAR and WAW information for it.  */
> +  if (dump_enabled_p ())
> +    dump_printf (MSG_NOTE, "merged alias checks:\n");
>    FOR_EACH_VEC_ELT (*alias_pairs, i, alias_pair)
>      {
>        unsigned int swap_mask = (DR_ALIAS_SWAPPED | DR_ALIAS_UNSWAPPED);
> @@ -1665,6 +1715,8 @@ prune_runtime_alias_test_list (vec<dr_wi
>        else if (swapped != DR_ALIAS_UNSWAPPED)
>         alias_pair->flags |= DR_ALIAS_ARBITRARY;
>        alias_pair->flags &= ~swap_mask;
> +      if (dump_enabled_p ())
> +       dump_alias_pair (alias_pair, "  ");
>      }
>  }
>
> Index: gcc/testsuite/gcc.dg/vect/vect-alias-check-8.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/vect/vect-alias-check-8.c      2019-03-08 18:15:02.280871184 +0000
> +++ gcc/testsuite/gcc.dg/vect/vect-alias-check-8.c      2019-11-11 18:30:57.167147102 +0000
> @@ -58,3 +58,5 @@ main (void)
>    FOR_EACH_TYPE (DO_TEST)
>    return 0;
>  }
> +
> +/* { dg-final { scan-tree-dump {flags: *WAR\n} "vect" { target vect_int } } } */
> Index: gcc/testsuite/gcc.dg/vect/vect-alias-check-9.c
> ===================================================================
> --- gcc/testsuite/gcc.dg/vect/vect-alias-check-9.c      2019-03-08 18:15:02.244871320 +0000
> +++ gcc/testsuite/gcc.dg/vect/vect-alias-check-9.c      2019-11-11 18:30:57.167147102 +0000
> @@ -17,7 +17,7 @@ #define FOR_EACH_TYPE(M) \
>    M (sll) M (ull) \
>    M (float) M (double)
>
> -#define TEST_VALUE(I) ((I) * 5 / 2)
> +#define TEST_VALUE(I) ((I) * 17 / 2)
>
>  #define ADD_TEST(TYPE)                         \
>    void __attribute__((noinline, noclone))      \
> @@ -51,3 +51,5 @@ main (void)
>    FOR_EACH_TYPE (DO_TEST)
>    return 0;
>  }
> +
> +/* { dg-final { scan-tree-dump {flags: [^\n]*ARBITRARY\n} "vect" { target vect_int } } } */
> Index: gcc/testsuite/gcc.dg/vect/vect-alias-check-14.c
> ===================================================================
> --- /dev/null   2019-09-17 11:41:18.176664108 +0100
> +++ gcc/testsuite/gcc.dg/vect/vect-alias-check-14.c     2019-11-11 18:30:57.167147102 +0000
> @@ -0,0 +1,62 @@
> +#define N 200
> +#define M 4
> +
> +typedef signed char sc;
> +typedef unsigned char uc;
> +typedef signed short ss;
> +typedef unsigned short us;
> +typedef int si;
> +typedef unsigned int ui;
> +typedef signed long long sll;
> +typedef unsigned long long ull;
> +
> +#define FOR_EACH_TYPE(M) \
> +  M (sc) M (uc) \
> +  M (ss) M (us) \
> +  M (si) M (ui) \
> +  M (sll) M (ull) \
> +  M (float) M (double)
> +
> +#define TEST_VALUE(I) ((I) * 17 / 2)
> +
> +#define ADD_TEST(TYPE)                         \
> +  void __attribute__((noinline, noclone))      \
> +  test_##TYPE (TYPE *a, TYPE *b)               \
> +  {                                            \
> +    for (int i = 0; i < N; i += 2)             \
> +      {                                                \
> +       TYPE b0 = b[i + 0];                     \
> +       TYPE b1 = b[i + 1];                     \
> +       a[i + 0] = b0 + 2;                      \
> +       a[i + 1] = b1 + 3;                      \
> +      }                                                \
> +  }
> +
> +#define DO_TEST(TYPE)                                          \
> +  for (int j = 0; j < M; ++j)                                  \
> +    {                                                          \
> +      TYPE a[N + M];                                           \
> +      for (int i = 0; i < N + M; ++i)                          \
> +       a[i] = TEST_VALUE (i);                                  \
> +      test_##TYPE (a + j, a);                                  \
> +      for (int i = 0; i < N; i += 2)                           \
> +       {                                                       \
> +         TYPE base1 = j == 0 ? TEST_VALUE (i) : a[i];          \
> +         TYPE base2 = j <= 1 ? TEST_VALUE (i + 1) : a[i + 1];  \
> +         if (a[i + j] != (TYPE) (base1 + 2)                    \
> +             || a[i + j + 1] != (TYPE) (base2 + 3))            \
> +           __builtin_abort ();                                 \
> +       }                                                       \
> +    }
> +
> +FOR_EACH_TYPE (ADD_TEST)
> +
> +int
> +main (void)
> +{
> +  FOR_EACH_TYPE (DO_TEST)
> +  return 0;
> +}
> +
> +/* { dg-final { scan-tree-dump {flags: *WAR\n} "vect" { target vect_int } } } */
> +/* { dg-final { scan-tree-dump-not {flags: [^\n]*ARBITRARY\n} "vect" } } */
> Index: gcc/testsuite/gcc.dg/vect/vect-alias-check-15.c
> ===================================================================
> --- /dev/null   2019-09-17 11:41:18.176664108 +0100
> +++ gcc/testsuite/gcc.dg/vect/vect-alias-check-15.c     2019-11-11 18:30:57.167147102 +0000
> @@ -0,0 +1,59 @@
> +#define N 200
> +#define DIST 32
> +
> +typedef signed char sc;
> +typedef unsigned char uc;
> +typedef signed short ss;
> +typedef unsigned short us;
> +typedef int si;
> +typedef unsigned int ui;
> +typedef signed long long sll;
> +typedef unsigned long long ull;
> +
> +#define FOR_EACH_TYPE(M) \
> +  M (sc) M (uc) \
> +  M (ss) M (us) \
> +  M (si) M (ui) \
> +  M (sll) M (ull) \
> +  M (float) M (double)
> +
> +#define ADD_TEST(TYPE)                         \
> +  void __attribute__((noinline, noclone))      \
> +  test_##TYPE (TYPE *x, TYPE *y)               \
> +  {                                            \
> +    for (int i = 0; i < N; ++i)                        \
> +      {                                                \
> +       x[i] = i;                               \
> +       y[i] = 42 - i * 2;                      \
> +      }                                                \
> +  }
> +
> +#define DO_TEST(TYPE)                                          \
> +  for (int i = 0; i < DIST * 2; ++i)                           \
> +    {                                                          \
> +      TYPE a[N + DIST * 2] = {};                               \
> +      test_##TYPE (a + DIST, a + i);                           \
> +      for (int j = 0; j < N + DIST * 2; ++j)                   \
> +       {                                                       \
> +         TYPE expected = 0;                                    \
> +         if (i > DIST && j >= i && j < i + N)                  \
> +           expected = 42 - (j - i) * 2;                        \
> +         if (j >= DIST && j < DIST + N)                        \
> +           expected = j - DIST;                                \
> +         if (i <= DIST && j >= i && j < i + N)                 \
> +           expected = 42 - (j - i) * 2;                        \
> +         if (expected != a[j])                                 \
> +           __builtin_abort ();                                 \
> +       }                                                       \
> +    }
> +
> +FOR_EACH_TYPE (ADD_TEST)
> +
> +int
> +main (void)
> +{
> +  FOR_EACH_TYPE (DO_TEST)
> +  return 0;
> +}
> +
> +/* { dg-final { scan-tree-dump {flags: *WAW\n} "vect" { target vect_int } } } */
> Index: gcc/testsuite/gcc.dg/vect/vect-alias-check-16.c
> ===================================================================
> --- /dev/null   2019-09-17 11:41:18.176664108 +0100
> +++ gcc/testsuite/gcc.dg/vect/vect-alias-check-16.c     2019-11-11 18:30:57.167147102 +0000
> @@ -0,0 +1,64 @@
> +#define N 200
> +#define DIST 32
> +
> +typedef signed char sc;
> +typedef unsigned char uc;
> +typedef signed short ss;
> +typedef unsigned short us;
> +typedef int si;
> +typedef unsigned int ui;
> +typedef signed long long sll;
> +typedef unsigned long long ull;
> +
> +#define FOR_EACH_TYPE(M) \
> +  M (sc) M (uc) \
> +  M (ss) M (us) \
> +  M (si) M (ui) \
> +  M (sll) M (ull) \
> +  M (float) M (double)
> +
> +#define TEST_VALUE(I) ((I) * 13 / 2)
> +
> +#define ADD_TEST(TYPE)                         \
> +  TYPE __attribute__((noinline, noclone))      \
> +  test_##TYPE (TYPE *x, TYPE *y)               \
> +  {                                            \
> +    TYPE res = 0;                              \
> +    for (int i = 0; i < N; ++i)                        \
> +      {                                                \
> +       x[i] = i;                               \
> +       res += y[i];                            \
> +      }                                                \
> +    return res;                                        \
> +  }
> +
> +#define DO_TEST(TYPE)                                          \
> +  for (int i = 0; i < DIST * 2; ++i)                           \
> +    {                                                          \
> +      TYPE a[N + DIST * 2];                                    \
> +      for (int j = 0; j < N + DIST * 2; ++j)                   \
> +       a[j] = TEST_VALUE (j);                                  \
> +      TYPE res = test_##TYPE (a + DIST, a + i);                        \
> +      for (int j = 0; j < N; ++j)                              \
> +       if (a[j + DIST] != (TYPE) j)                            \
> +         __builtin_abort ();                                   \
> +      TYPE expected_res = 0;                                   \
> +      for (int j = i; j < i + N; ++j)                          \
> +       if (i <= DIST && j >= DIST && j < DIST + N)             \
> +         expected_res += j - DIST;                             \
> +       else                                                    \
> +         expected_res += TEST_VALUE (j);                       \
> +      if (expected_res != res)                                 \
> +       __builtin_abort ();                                     \
> +    }
> +
> +FOR_EACH_TYPE (ADD_TEST)
> +
> +int
> +main (void)
> +{
> +  FOR_EACH_TYPE (DO_TEST)
> +  return 0;
> +}
> +
> +/* { dg-final { scan-tree-dump {flags: *RAW\n} "vect" { target vect_int } } } */
> Index: gcc/testsuite/gcc.dg/vect/vect-alias-check-17.c
> ===================================================================
> --- /dev/null   2019-09-17 11:41:18.176664108 +0100
> +++ gcc/testsuite/gcc.dg/vect/vect-alias-check-17.c     2019-11-11 18:30:57.167147102 +0000
> @@ -0,0 +1,13 @@
> +/* { dg-do compile } */
> +/* { dg-require-effective-target vect_load_lanes } */
> +
> +struct s { int x[100]; };
> +
> +void
> +f (struct s *s1, int a, int b)
> +{
> +  for (int i = 0; i < 32; ++i)
> +    s1->x[a + i] = s1->x[b + i * 2] + s1->x[b + i * 3];
> +}
> +
> +/* { dg-final { scan-tree-dump {flags: *[^\n]*MIXED_STEPS} "vect" } } */