[1/2] PHI-OPT [PR 110984]: Add support for NE_EXPR/EQ_EXPR with casts to spaceship_replacement

  So with my next VRP patch, VRP causes:
```
  # c$_M_value_18 = PHI <-1(3), 0(2), 1(4)>
  _11 = (unsigned int) c$_M_value_18;
  _16 = _11 <= 1;
```
To be changed to:
```
  # c$_M_value_18 = PHI <-1(3), 0(2), 1(4)>
  _11 = (unsigned int) c$_M_value_18;
  _16 = _11 != 4294967295;
```

So let's add support for the above.
A few changes was needed, first to change
the range check of the rhs of the comparison to possibly
integer_all_onesp also.

The next is to add support for the cast and EQ/NE case.

Note on the testcases pr110984-1.c is basically pr94589-2.c but
with what the C++ code is doing with the signed char type;
pr110984-2.c is pr110984-1.c with the cast added to give an
explicit testcase to test against.

OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

Thanks,
Andrew Pinski

	PR tree-optimization/110984

gcc/ChangeLog:

	* tree-ssa-phiopt.cc (spaceship_replacement): Add support for
	NE/EQ for the cast case.

gcc/testsuite/ChangeLog:

	* gcc.dg/pr110984-1.c: New test.
	* gcc.dg/pr110984-2.c: New test.
---
 gcc/testsuite/gcc.dg/pr110984-1.c | 37 +++++++++++++++++++++++++++++++
 gcc/testsuite/gcc.dg/pr110984-2.c | 21 ++++++++++++++++++
 gcc/tree-ssa-phiopt.cc            | 19 +++++++++++++---
 3 files changed, 74 insertions(+), 3 deletions(-)
 create mode 100644 gcc/testsuite/gcc.dg/pr110984-1.c
 create mode 100644 gcc/testsuite/gcc.dg/pr110984-2.c
  

On Fri, Aug 11, 2023 at 11:17 AM Andrew Pinski via Gcc-patches
<gcc-patches@gcc.gnu.org> wrote:
>
> So with my next VRP patch, VRP causes:
> ```
>   # c$_M_value_18 = PHI <-1(3), 0(2), 1(4)>
>   _11 = (unsigned int) c$_M_value_18;
>   _16 = _11 <= 1;
> ```
> To be changed to:
> ```
>   # c$_M_value_18 = PHI <-1(3), 0(2), 1(4)>
>   _11 = (unsigned int) c$_M_value_18;
>   _16 = _11 != 4294967295;
> ```
>
> So let's add support for the above.
> A few changes was needed, first to change
> the range check of the rhs of the comparison to possibly
> integer_all_onesp also.
>
> The next is to add support for the cast and EQ/NE case.
>
> Note on the testcases pr110984-1.c is basically pr94589-2.c but
> with what the C++ code is doing with the signed char type;
> pr110984-2.c is pr110984-1.c with the cast added to give an
> explicit testcase to test against.
>
> OK? Bootstrapped and tested on x86_64-linux-gnu with no regressions.

LGTM.

> Thanks,
> Andrew Pinski
>
>         PR tree-optimization/110984
>
> gcc/ChangeLog:
>
>         * tree-ssa-phiopt.cc (spaceship_replacement): Add support for
>         NE/EQ for the cast case.
>
> gcc/testsuite/ChangeLog:
>
>         * gcc.dg/pr110984-1.c: New test.
>         * gcc.dg/pr110984-2.c: New test.
> ---
>  gcc/testsuite/gcc.dg/pr110984-1.c | 37 +++++++++++++++++++++++++++++++
>  gcc/testsuite/gcc.dg/pr110984-2.c | 21 ++++++++++++++++++
>  gcc/tree-ssa-phiopt.cc            | 19 +++++++++++++---
>  3 files changed, 74 insertions(+), 3 deletions(-)
>  create mode 100644 gcc/testsuite/gcc.dg/pr110984-1.c
>  create mode 100644 gcc/testsuite/gcc.dg/pr110984-2.c
>
> diff --git a/gcc/testsuite/gcc.dg/pr110984-1.c b/gcc/testsuite/gcc.dg/pr110984-1.c
> new file mode 100644
> index 00000000000..85b19eb8279
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr110984-1.c
> @@ -0,0 +1,37 @@
> +/* PR tree-optimization/110984 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -g0 -ffast-math -fdump-tree-optimized" } */
> +/* { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) \[ij]_\[0-9]+\\(D\\)" 14 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "i_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) 5\\.0" 14 "optimized" } } */
> +
> +/* This is similar to pr94589-2.c except use signed char as the type for the [-1,2] case */
> +
> +#define A __attribute__((noipa))
> +A int f1 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c == 0; }
> +A int f2 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c != 0; }
> +A int f3 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c > 0; }
> +A int f4 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c < 0; }
> +A int f5 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c >= 0; }
> +A int f6 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c <= 0; }
> +A int f7 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c == -1; }
> +A int f8 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c != -1; }
> +A int f9 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c > -1; }
> +A int f10 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c <= -1; }
> +A int f11 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c == 1; }
> +A int f12 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c != 1; }
> +A int f13 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c < 1; }
> +A int f14 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; return c >= 1; }
> +A int f15 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c == 0; }
> +A int f16 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c != 0; }
> +A int f17 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c > 0; }
> +A int f18 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c < 0; }
> +A int f19 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c >= 0; }
> +A int f20 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c <= 0; }
> +A int f21 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c == -1; }
> +A int f22 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c != -1; }
> +A int f23 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c > -1; }
> +A int f24 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c <= -1; }
> +A int f25 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c == 1; }
> +A int f26 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c != 1; }
> +A int f27 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c < 1; }
> +A int f28 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; return c >= 1; }
> diff --git a/gcc/testsuite/gcc.dg/pr110984-2.c b/gcc/testsuite/gcc.dg/pr110984-2.c
> new file mode 100644
> index 00000000000..cddce045745
> --- /dev/null
> +++ b/gcc/testsuite/gcc.dg/pr110984-2.c
> @@ -0,0 +1,21 @@
> +/* PR tree-optimization/110984 */
> +/* { dg-do compile } */
> +/* { dg-options "-O2 -g0 -ffast-math -fdump-tree-optimized" } */
> +/* { dg-final { scan-tree-dump-times "\[ij]_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) \[ij]_\[0-9]+\\(D\\)" 6 "optimized" } } */
> +/* { dg-final { scan-tree-dump-times "i_\[0-9]+\\(D\\) (?:<|<=|==|!=|>|>=) 5\\.0" 6 "optimized" } } */
> +
> +/* This is similar to pr94589-2.c except use signed char and use unsigned types to check against the variable, which means removing the non !=/== comparisons.  */
> +
> +#define A __attribute__((noipa))
> +A int f1 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t == 0; }
> +A int f2 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t != 0; }
> +A int f7 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t == -1; }
> +A int f8 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t != -1; }
> +A int f11 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t == 1; }
> +A int f12 (double i, double j) { signed char c; if (i == j) c = 0; else if (i < j) c = -1; else if (i > j) c = 1; else c = 2; unsigned t = c; return t != 1; }
> +A int f15 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t == 0; }
> +A int f16 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t != 0; }
> +A int f21 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t == -1; }
> +A int f22 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t != -1; }
> +A int f25 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t == 1; }
> +A int f26 (double i) { signed char c; if (i == 5.0) c = 0; else if (i < 5.0) c = -1; else if (i > 5.0) c = 1; else c = 2; unsigned t = c; return t != 1; }
> diff --git a/gcc/tree-ssa-phiopt.cc b/gcc/tree-ssa-phiopt.cc
> index 485662dfcc7..5f24d62c49a 100644
> --- a/gcc/tree-ssa-phiopt.cc
> +++ b/gcc/tree-ssa-phiopt.cc
> @@ -2346,7 +2346,8 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
>      }
>    if (lhs != (orig_use_lhs ? orig_use_lhs : phires)
>        || !tree_fits_shwi_p (rhs)
> -      || !IN_RANGE (tree_to_shwi (rhs), -1, 1))
> +      || !(IN_RANGE (tree_to_shwi (rhs), 0, 1)
> +          || integer_all_onesp (rhs)))
>      return false;
>
>    if (is_cast)
> @@ -2356,9 +2357,20 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
>        /* As for -ffast-math we assume the 2 return to be
>          impossible, canonicalize (unsigned) res <= 1U or
>          (unsigned) res < 2U into res >= 0 and (unsigned) res > 1U
> -        or (unsigned) res >= 2U as res < 0.  */
> +        or (unsigned) res >= 2U as res < 0.
> +        Sometimes we get (unsigned)res != N.  Support those cases too. */
>        switch (cmp)
>         {
> +       case NE_EXPR:
> +       case EQ_EXPR:
> +         {
> +           tree newrhs = fold_convert (TREE_TYPE (phires), rhs);
> +           tree tmp = fold_convert (TREE_TYPE (rhs), newrhs);
> +           if (!tree_int_cst_equal (rhs, tmp))
> +             return false;
> +           rhs = newrhs;
> +           break;
> +         }
>         case LE_EXPR:
>           if (!integer_onep (rhs))
>             return false;
> @@ -2382,7 +2394,8 @@ spaceship_replacement (basic_block cond_bb, basic_block middle_bb,
>         default:
>           return false;
>         }
> -      rhs = build_zero_cst (TREE_TYPE (phires));
> +      if (cmp != EQ_EXPR && cmp != NE_EXPR)
> +       rhs = build_zero_cst (TREE_TYPE (phires));
>      }
>    else if (orig_use_lhs)
>      {
> --
> 2.31.1
>