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[v2] Match: Support form 1 for scalar signed integer .SAT_ADD

Message ID 20240807093049.1327622-1-pan2.li@intel.com
State New
Headers show
Series [v2] Match: Support form 1 for scalar signed integer .SAT_ADD | expand

Commit Message

Li, Pan2 Aug. 7, 2024, 9:30 a.m. UTC 
From: Pan Li <pan2.li@intel.com>

This patch would like to support the form 1 of the scalar signed
integer .SAT_ADD.  Aka below example:

Form 1:
  #define DEF_SAT_S_ADD_FMT_1(T, MIN, MAX) \
  T __attribute__((noinline))              \
  sat_s_add_##T##_fmt_1 (T x, T y)         \
  {                                        \
    T sum = x + y;                         \
    return (x ^ y) < 0                     \
      ? sum                                \
      : (sum ^ x) >= 0                     \
        ? sum                              \
        : x < 0 ? MIN : MAX;               \
  }

DEF_SAT_S_ADD_FMT_1(int64_t, INT64_MIN, INT64_MAX)

We can tell the difference before and after this patch if backend
implemented the ssadd<m>3 pattern similar as below.

Before this patch:
   4   │ __attribute__((noinline))
   5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
   6   │ {
   7   │   int64_t sum;
   8   │   long int _1;
   9   │   long int _2;
  10   │   int64_t _3;
  11   │   _Bool _8;
  12   │   long int _9;
  13   │   long int _10;
  14   │   long int _11;
  15   │   long int _12;
  16   │   long int _13;
  17   │
  18   │   <bb 2> [local count: 1073741824]:
  19   │   sum_6 = x_4(D) + y_5(D);
  20   │   _1 = x_4(D) ^ y_5(D);
  21   │   _2 = x_4(D) ^ sum_6;
  22   │   _12 = ~_1;
  23   │   _13 = _2 & _12;
  24   │   if (_13 < 0)
  25   │     goto <bb 3>; [41.00%]
  26   │   else
  27   │     goto <bb 4>; [59.00%]
  28   │
  29   │   <bb 3> [local count: 259738147]:
  30   │   _8 = x_4(D) < 0;
  31   │   _9 = (long int) _8;
  32   │   _10 = -_9;
  33   │   _11 = _10 ^ 9223372036854775807;
  34   │
  35   │   <bb 4> [local count: 1073741824]:
  36   │   # _3 = PHI <sum_6(2), _11(3)>
  37   │   return _3;
  38   │
  39   │ }

After this patch:
   4   │ __attribute__((noinline))
   5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
   6   │ {
   7   │   int64_t _4;
   8   │
   9   │ ;;   basic block 2, loop depth 0
  10   │ ;;    pred:       ENTRY
  11   │   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]
  12   │   return _4;
  13   │ ;;    succ:       EXIT
  14   │
  15   │ }

The below test suites are passed for this patch.
* The rv64gcv fully regression test.
* The x86 bootstrap test.
* The x86 fully regression test.

gcc/ChangeLog:

	* match.pd: Add the matching for signed .SAT_ADD.
	* tree-ssa-math-opts.cc (gimple_signed_integer_sat_add): Add new
	matching func decl.
	(match_unsigned_saturation_add): Try signed .SAT_ADD and rename
	to ...
	(match_saturation_add): ... here.
	(math_opts_dom_walker::after_dom_children): Update the above renamed
	func from caller.

Signed-off-by: Pan Li <pan2.li@intel.com>
---
 gcc/match.pd              | 17 ++++++++++++++++
 gcc/tree-ssa-math-opts.cc | 42 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 54 insertions(+), 5 deletions(-)

Comments

Li, Pan2 Aug. 20, 2024, 2:30 a.m. UTC | #1 
Kindly ping.

Pan

-----Original Message-----
From: Li, Pan2 <pan2.li@intel.com> 
Sent: Wednesday, August 7, 2024 5:31 PM
To: gcc-patches@gcc.gnu.org
Cc: richard.guenther@gmail.com; juzhe.zhong@rivai.ai; kito.cheng@gmail.com; jeffreyalaw@gmail.com; rdapp.gcc@gmail.com; Li, Pan2 <pan2.li@intel.com>
Subject: [PATCH v2] Match: Support form 1 for scalar signed integer .SAT_ADD

From: Pan Li <pan2.li@intel.com>

This patch would like to support the form 1 of the scalar signed
integer .SAT_ADD.  Aka below example:

Form 1:
  #define DEF_SAT_S_ADD_FMT_1(T, MIN, MAX) \
  T __attribute__((noinline))              \
  sat_s_add_##T##_fmt_1 (T x, T y)         \
  {                                        \
    T sum = x + y;                         \
    return (x ^ y) < 0                     \
      ? sum                                \
      : (sum ^ x) >= 0                     \
        ? sum                              \
        : x < 0 ? MIN : MAX;               \
  }

DEF_SAT_S_ADD_FMT_1(int64_t, INT64_MIN, INT64_MAX)

We can tell the difference before and after this patch if backend
implemented the ssadd<m>3 pattern similar as below.

Before this patch:
   4   │ __attribute__((noinline))
   5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
   6   │ {
   7   │   int64_t sum;
   8   │   long int _1;
   9   │   long int _2;
  10   │   int64_t _3;
  11   │   _Bool _8;
  12   │   long int _9;
  13   │   long int _10;
  14   │   long int _11;
  15   │   long int _12;
  16   │   long int _13;
  17   │
  18   │   <bb 2> [local count: 1073741824]:
  19   │   sum_6 = x_4(D) + y_5(D);
  20   │   _1 = x_4(D) ^ y_5(D);
  21   │   _2 = x_4(D) ^ sum_6;
  22   │   _12 = ~_1;
  23   │   _13 = _2 & _12;
  24   │   if (_13 < 0)
  25   │     goto <bb 3>; [41.00%]
  26   │   else
  27   │     goto <bb 4>; [59.00%]
  28   │
  29   │   <bb 3> [local count: 259738147]:
  30   │   _8 = x_4(D) < 0;
  31   │   _9 = (long int) _8;
  32   │   _10 = -_9;
  33   │   _11 = _10 ^ 9223372036854775807;
  34   │
  35   │   <bb 4> [local count: 1073741824]:
  36   │   # _3 = PHI <sum_6(2), _11(3)>
  37   │   return _3;
  38   │
  39   │ }

After this patch:
   4   │ __attribute__((noinline))
   5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
   6   │ {
   7   │   int64_t _4;
   8   │
   9   │ ;;   basic block 2, loop depth 0
  10   │ ;;    pred:       ENTRY
  11   │   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]
  12   │   return _4;
  13   │ ;;    succ:       EXIT
  14   │
  15   │ }

The below test suites are passed for this patch.
* The rv64gcv fully regression test.
* The x86 bootstrap test.
* The x86 fully regression test.

gcc/ChangeLog:

	* match.pd: Add the matching for signed .SAT_ADD.
	* tree-ssa-math-opts.cc (gimple_signed_integer_sat_add): Add new
	matching func decl.
	(match_unsigned_saturation_add): Try signed .SAT_ADD and rename
	to ...
	(match_saturation_add): ... here.
	(math_opts_dom_walker::after_dom_children): Update the above renamed
	func from caller.

Signed-off-by: Pan Li <pan2.li@intel.com>
---
 gcc/match.pd              | 17 ++++++++++++++++
 gcc/tree-ssa-math-opts.cc | 42 ++++++++++++++++++++++++++++++++++-----
 2 files changed, 54 insertions(+), 5 deletions(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index c9c8478d286..8b8a5dbcfe3 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3311,6 +3311,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   }
   (if (otype_precision < itype_precision && wi::eq_p (trunc_max, int_cst))))))
 
+/* Signed saturation add, case 1:
+   T sum = X + Y;
+   SAT_S_ADD = (X ^ Y) < 0
+     ? sum
+     : (sum ^ x) >= 0
+       ? sum
+       : x < 0 ? MIN : MAX;  */
+(match (signed_integer_sat_add @0 @1)
+ (cond^ (lt (bit_and:c (bit_xor:c @0 (convert?@2 (plus:c (convert? @0)
+							 (convert? @1))))
+		       (bit_not (bit_xor:c @0 @1)))
+	    integer_zerop)
+	(bit_xor:c (negate (convert (lt @0 integer_zerop))) max_value)
+	@2)
+ (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type)
+      && types_match (type, @0, @1))))
+
 /* x >  y  &&  x != XXX_MIN  -->  x > y
    x >  y  &&  x == XXX_MIN  -->  false . */
 (for eqne (eq ne)
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 8d96a4c964b..f39c88741a4 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -4023,6 +4023,8 @@ extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
 extern bool gimple_unsigned_integer_sat_sub (tree, tree*, tree (*)(tree));
 extern bool gimple_unsigned_integer_sat_trunc (tree, tree*, tree (*)(tree));
 
+extern bool gimple_signed_integer_sat_add (tree, tree*, tree (*)(tree));
+
 static void
 build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
 				    tree lhs, tree op_0, tree op_1)
@@ -4072,7 +4074,8 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
 }
 
 /*
- * Try to match saturation unsigned add with PHI.
+ * Try to match saturation add with PHI.
+ * For unsigned integer:
  *   <bb 2> :
  *   _1 = x_3(D) + y_4(D);
  *   if (_1 >= x_3(D))
@@ -4086,10 +4089,38 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
  *   # _2 = PHI <255(2), _1(3)>
  *   =>
  *   <bb 4> [local count: 1073741824]:
- *   _2 = .SAT_ADD (x_4(D), y_5(D));  */
+ *   _2 = .SAT_ADD (x_4(D), y_5(D));
+ *
+ * For signed integer:
+ *   _1 = x_5(D) ^ y_6(D);
+ *   _13 = x_5(D) + y_6(D);
+ *   _3 = x_5(D) ^ _13;
+ *   _2 = ~_1;
+ *   _7 = _2 & _3;
+ *   if (_7 < 0)
+ *     goto <bb 3>; [59.00%]
+ *   else
+ *     goto <bb 4>; [41.00%]
+ *   ;;    succ:       4
+ *   ;;                3
+ *   ;;   basic block 3, loop depth 0
+ *   ;;    pred:       2
+ *   _9 = x_5(D) < 0;
+ *   _10 = (long int) _9;
+ *   _11 = -_10;
+ *   _12 = _11 ^ 9223372036854775807;
+ *   ;;    succ:       4
+ *   ;;   basic block 4, loop depth 0
+ *   ;;    pred:       2
+ *   ;;                3
+ *   # _4 = PHI <_13(2), _12(3)>
+ *   =>
+ *   ;;   basic block 2, loop depth 0
+ *   ;;    pred:       ENTRY
+ *   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]  */
 
 static void
-match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
+match_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
 {
   if (gimple_phi_num_args (phi) != 2)
     return;
@@ -4097,7 +4128,8 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
   tree ops[2];
   tree phi_result = gimple_phi_result (phi);
 
-  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL))
+  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL)
+      || gimple_signed_integer_sat_add (phi_result, ops, NULL))
     build_saturation_binary_arith_call (gsi, phi, IFN_SAT_ADD, phi_result,
 					ops[0], ops[1]);
 }
@@ -6097,7 +6129,7 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
     gsi_next (&psi))
     {
       gimple_stmt_iterator gsi = gsi_after_labels (bb);
-      match_unsigned_saturation_add (&gsi, psi.phi ());
+      match_saturation_add (&gsi, psi.phi ());
       match_unsigned_saturation_sub (&gsi, psi.phi ());
     }
Richard Biener Aug. 22, 2024, 9:46 a.m. UTC | #2 
On Wed, Aug 7, 2024 at 11:31 AM <pan2.li@intel.com> wrote:
>
> From: Pan Li <pan2.li@intel.com>
>
> This patch would like to support the form 1 of the scalar signed
> integer .SAT_ADD.  Aka below example:
>
> Form 1:
>   #define DEF_SAT_S_ADD_FMT_1(T, MIN, MAX) \
>   T __attribute__((noinline))              \
>   sat_s_add_##T##_fmt_1 (T x, T y)         \
>   {                                        \
>     T sum = x + y;                         \
>     return (x ^ y) < 0                     \
>       ? sum                                \
>       : (sum ^ x) >= 0                     \
>         ? sum                              \
>         : x < 0 ? MIN : MAX;               \
>   }

Wow.  I wonder why this isn't simplified to never saturate since
signed x + y has undefined behavior on overflow?  So I'd
expect instead

  T sum = (unsigned T)x + (unsigned T)y;

to be used.

> DEF_SAT_S_ADD_FMT_1(int64_t, INT64_MIN, INT64_MAX)
>
> We can tell the difference before and after this patch if backend
> implemented the ssadd<m>3 pattern similar as below.
>
> Before this patch:
>    4   │ __attribute__((noinline))
>    5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
>    6   │ {
>    7   │   int64_t sum;
>    8   │   long int _1;
>    9   │   long int _2;
>   10   │   int64_t _3;
>   11   │   _Bool _8;
>   12   │   long int _9;
>   13   │   long int _10;
>   14   │   long int _11;
>   15   │   long int _12;
>   16   │   long int _13;
>   17   │
>   18   │   <bb 2> [local count: 1073741824]:
>   19   │   sum_6 = x_4(D) + y_5(D);
>   20   │   _1 = x_4(D) ^ y_5(D);
>   21   │   _2 = x_4(D) ^ sum_6;
>   22   │   _12 = ~_1;
>   23   │   _13 = _2 & _12;
>   24   │   if (_13 < 0)
>   25   │     goto <bb 3>; [41.00%]
>   26   │   else
>   27   │     goto <bb 4>; [59.00%]
>   28   │
>   29   │   <bb 3> [local count: 259738147]:
>   30   │   _8 = x_4(D) < 0;
>   31   │   _9 = (long int) _8;
>   32   │   _10 = -_9;
>   33   │   _11 = _10 ^ 9223372036854775807;
>   34   │
>   35   │   <bb 4> [local count: 1073741824]:
>   36   │   # _3 = PHI <sum_6(2), _11(3)>
>   37   │   return _3;
>   38   │
>   39   │ }
>
> After this patch:
>    4   │ __attribute__((noinline))
>    5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
>    6   │ {
>    7   │   int64_t _4;
>    8   │
>    9   │ ;;   basic block 2, loop depth 0
>   10   │ ;;    pred:       ENTRY
>   11   │   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]
>   12   │   return _4;
>   13   │ ;;    succ:       EXIT
>   14   │
>   15   │ }
>
> The below test suites are passed for this patch.
> * The rv64gcv fully regression test.
> * The x86 bootstrap test.
> * The x86 fully regression test.
>
> gcc/ChangeLog:
>
>         * match.pd: Add the matching for signed .SAT_ADD.
>         * tree-ssa-math-opts.cc (gimple_signed_integer_sat_add): Add new
>         matching func decl.
>         (match_unsigned_saturation_add): Try signed .SAT_ADD and rename
>         to ...
>         (match_saturation_add): ... here.
>         (math_opts_dom_walker::after_dom_children): Update the above renamed
>         func from caller.
>
> Signed-off-by: Pan Li <pan2.li@intel.com>
> ---
>  gcc/match.pd              | 17 ++++++++++++++++
>  gcc/tree-ssa-math-opts.cc | 42 ++++++++++++++++++++++++++++++++++-----
>  2 files changed, 54 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index c9c8478d286..8b8a5dbcfe3 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3311,6 +3311,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    }
>    (if (otype_precision < itype_precision && wi::eq_p (trunc_max, int_cst))))))
>
> +/* Signed saturation add, case 1:
> +   T sum = X + Y;
> +   SAT_S_ADD = (X ^ Y) < 0
> +     ? sum
> +     : (sum ^ x) >= 0
> +       ? sum
> +       : x < 0 ? MIN : MAX;  */
> +(match (signed_integer_sat_add @0 @1)
> + (cond^ (lt (bit_and:c (bit_xor:c @0 (convert?@2 (plus:c (convert? @0)
> +                                                        (convert? @1))))
> +                      (bit_not (bit_xor:c @0 @1)))
> +           integer_zerop)
> +       (bit_xor:c (negate (convert (lt @0 integer_zerop))) max_value)
> +       @2)
> + (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type)
> +      && types_match (type, @0, @1))))
> +
>  /* x >  y  &&  x != XXX_MIN  -->  x > y
>     x >  y  &&  x == XXX_MIN  -->  false . */
>  (for eqne (eq ne)
> diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
> index 8d96a4c964b..f39c88741a4 100644
> --- a/gcc/tree-ssa-math-opts.cc
> +++ b/gcc/tree-ssa-math-opts.cc
> @@ -4023,6 +4023,8 @@ extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
>  extern bool gimple_unsigned_integer_sat_sub (tree, tree*, tree (*)(tree));
>  extern bool gimple_unsigned_integer_sat_trunc (tree, tree*, tree (*)(tree));
>
> +extern bool gimple_signed_integer_sat_add (tree, tree*, tree (*)(tree));
> +
>  static void
>  build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
>                                     tree lhs, tree op_0, tree op_1)
> @@ -4072,7 +4074,8 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
>  }
>
>  /*
> - * Try to match saturation unsigned add with PHI.
> + * Try to match saturation add with PHI.
> + * For unsigned integer:
>   *   <bb 2> :
>   *   _1 = x_3(D) + y_4(D);
>   *   if (_1 >= x_3(D))
> @@ -4086,10 +4089,38 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
>   *   # _2 = PHI <255(2), _1(3)>
>   *   =>
>   *   <bb 4> [local count: 1073741824]:
> - *   _2 = .SAT_ADD (x_4(D), y_5(D));  */
> + *   _2 = .SAT_ADD (x_4(D), y_5(D));
> + *
> + * For signed integer:
> + *   _1 = x_5(D) ^ y_6(D);
> + *   _13 = x_5(D) + y_6(D);
> + *   _3 = x_5(D) ^ _13;
> + *   _2 = ~_1;
> + *   _7 = _2 & _3;
> + *   if (_7 < 0)
> + *     goto <bb 3>; [59.00%]
> + *   else
> + *     goto <bb 4>; [41.00%]
> + *   ;;    succ:       4
> + *   ;;                3
> + *   ;;   basic block 3, loop depth 0
> + *   ;;    pred:       2
> + *   _9 = x_5(D) < 0;
> + *   _10 = (long int) _9;
> + *   _11 = -_10;
> + *   _12 = _11 ^ 9223372036854775807;
> + *   ;;    succ:       4
> + *   ;;   basic block 4, loop depth 0
> + *   ;;    pred:       2
> + *   ;;                3
> + *   # _4 = PHI <_13(2), _12(3)>
> + *   =>
> + *   ;;   basic block 2, loop depth 0
> + *   ;;    pred:       ENTRY
> + *   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]  */
>
>  static void
> -match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
> +match_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
>  {
>    if (gimple_phi_num_args (phi) != 2)
>      return;
> @@ -4097,7 +4128,8 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
>    tree ops[2];
>    tree phi_result = gimple_phi_result (phi);
>
> -  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL))
> +  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL)
> +      || gimple_signed_integer_sat_add (phi_result, ops, NULL))
>      build_saturation_binary_arith_call (gsi, phi, IFN_SAT_ADD, phi_result,
>                                         ops[0], ops[1]);
>  }
> @@ -6097,7 +6129,7 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
>      gsi_next (&psi))
>      {
>        gimple_stmt_iterator gsi = gsi_after_labels (bb);
> -      match_unsigned_saturation_add (&gsi, psi.phi ());
> +      match_saturation_add (&gsi, psi.phi ());
>        match_unsigned_saturation_sub (&gsi, psi.phi ());
>      }
>
> --
> 2.43.0
>
Li, Pan2 Aug. 25, 2024, 2:12 a.m. UTC | #3 
> Wow.  I wonder why this isn't simplified to never saturate since
> signed x + y has undefined behavior on overflow?  So I'd
> expect instead
>  T sum = (unsigned T)x + (unsigned T)y;
> to be used.

Thanks, let me update in v3.

Pan

-----Original Message-----
From: Richard Biener <richard.guenther@gmail.com> 
Sent: Thursday, August 22, 2024 5:47 PM
To: Li, Pan2 <pan2.li@intel.com>
Cc: gcc-patches@gcc.gnu.org; juzhe.zhong@rivai.ai; kito.cheng@gmail.com; jeffreyalaw@gmail.com; rdapp.gcc@gmail.com
Subject: Re: [PATCH v2] Match: Support form 1 for scalar signed integer .SAT_ADD

On Wed, Aug 7, 2024 at 11:31 AM <pan2.li@intel.com> wrote:
>
> From: Pan Li <pan2.li@intel.com>
>
> This patch would like to support the form 1 of the scalar signed
> integer .SAT_ADD.  Aka below example:
>
> Form 1:
>   #define DEF_SAT_S_ADD_FMT_1(T, MIN, MAX) \
>   T __attribute__((noinline))              \
>   sat_s_add_##T##_fmt_1 (T x, T y)         \
>   {                                        \
>     T sum = x + y;                         \
>     return (x ^ y) < 0                     \
>       ? sum                                \
>       : (sum ^ x) >= 0                     \
>         ? sum                              \
>         : x < 0 ? MIN : MAX;               \
>   }

Wow.  I wonder why this isn't simplified to never saturate since
signed x + y has undefined behavior on overflow?  So I'd
expect instead

  T sum = (unsigned T)x + (unsigned T)y;

to be used.

> DEF_SAT_S_ADD_FMT_1(int64_t, INT64_MIN, INT64_MAX)
>
> We can tell the difference before and after this patch if backend
> implemented the ssadd<m>3 pattern similar as below.
>
> Before this patch:
>    4   │ __attribute__((noinline))
>    5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
>    6   │ {
>    7   │   int64_t sum;
>    8   │   long int _1;
>    9   │   long int _2;
>   10   │   int64_t _3;
>   11   │   _Bool _8;
>   12   │   long int _9;
>   13   │   long int _10;
>   14   │   long int _11;
>   15   │   long int _12;
>   16   │   long int _13;
>   17   │
>   18   │   <bb 2> [local count: 1073741824]:
>   19   │   sum_6 = x_4(D) + y_5(D);
>   20   │   _1 = x_4(D) ^ y_5(D);
>   21   │   _2 = x_4(D) ^ sum_6;
>   22   │   _12 = ~_1;
>   23   │   _13 = _2 & _12;
>   24   │   if (_13 < 0)
>   25   │     goto <bb 3>; [41.00%]
>   26   │   else
>   27   │     goto <bb 4>; [59.00%]
>   28   │
>   29   │   <bb 3> [local count: 259738147]:
>   30   │   _8 = x_4(D) < 0;
>   31   │   _9 = (long int) _8;
>   32   │   _10 = -_9;
>   33   │   _11 = _10 ^ 9223372036854775807;
>   34   │
>   35   │   <bb 4> [local count: 1073741824]:
>   36   │   # _3 = PHI <sum_6(2), _11(3)>
>   37   │   return _3;
>   38   │
>   39   │ }
>
> After this patch:
>    4   │ __attribute__((noinline))
>    5   │ int64_t sat_s_add_int64_t_fmt_1 (int64_t x, int64_t y)
>    6   │ {
>    7   │   int64_t _4;
>    8   │
>    9   │ ;;   basic block 2, loop depth 0
>   10   │ ;;    pred:       ENTRY
>   11   │   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]
>   12   │   return _4;
>   13   │ ;;    succ:       EXIT
>   14   │
>   15   │ }
>
> The below test suites are passed for this patch.
> * The rv64gcv fully regression test.
> * The x86 bootstrap test.
> * The x86 fully regression test.
>
> gcc/ChangeLog:
>
>         * match.pd: Add the matching for signed .SAT_ADD.
>         * tree-ssa-math-opts.cc (gimple_signed_integer_sat_add): Add new
>         matching func decl.
>         (match_unsigned_saturation_add): Try signed .SAT_ADD and rename
>         to ...
>         (match_saturation_add): ... here.
>         (math_opts_dom_walker::after_dom_children): Update the above renamed
>         func from caller.
>
> Signed-off-by: Pan Li <pan2.li@intel.com>
> ---
>  gcc/match.pd              | 17 ++++++++++++++++
>  gcc/tree-ssa-math-opts.cc | 42 ++++++++++++++++++++++++++++++++++-----
>  2 files changed, 54 insertions(+), 5 deletions(-)
>
> diff --git a/gcc/match.pd b/gcc/match.pd
> index c9c8478d286..8b8a5dbcfe3 100644
> --- a/gcc/match.pd
> +++ b/gcc/match.pd
> @@ -3311,6 +3311,23 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
>    }
>    (if (otype_precision < itype_precision && wi::eq_p (trunc_max, int_cst))))))
>
> +/* Signed saturation add, case 1:
> +   T sum = X + Y;
> +   SAT_S_ADD = (X ^ Y) < 0
> +     ? sum
> +     : (sum ^ x) >= 0
> +       ? sum
> +       : x < 0 ? MIN : MAX;  */
> +(match (signed_integer_sat_add @0 @1)
> + (cond^ (lt (bit_and:c (bit_xor:c @0 (convert?@2 (plus:c (convert? @0)
> +                                                        (convert? @1))))
> +                      (bit_not (bit_xor:c @0 @1)))
> +           integer_zerop)
> +       (bit_xor:c (negate (convert (lt @0 integer_zerop))) max_value)
> +       @2)
> + (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type)
> +      && types_match (type, @0, @1))))
> +
>  /* x >  y  &&  x != XXX_MIN  -->  x > y
>     x >  y  &&  x == XXX_MIN  -->  false . */
>  (for eqne (eq ne)
> diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
> index 8d96a4c964b..f39c88741a4 100644
> --- a/gcc/tree-ssa-math-opts.cc
> +++ b/gcc/tree-ssa-math-opts.cc
> @@ -4023,6 +4023,8 @@ extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
>  extern bool gimple_unsigned_integer_sat_sub (tree, tree*, tree (*)(tree));
>  extern bool gimple_unsigned_integer_sat_trunc (tree, tree*, tree (*)(tree));
>
> +extern bool gimple_signed_integer_sat_add (tree, tree*, tree (*)(tree));
> +
>  static void
>  build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
>                                     tree lhs, tree op_0, tree op_1)
> @@ -4072,7 +4074,8 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
>  }
>
>  /*
> - * Try to match saturation unsigned add with PHI.
> + * Try to match saturation add with PHI.
> + * For unsigned integer:
>   *   <bb 2> :
>   *   _1 = x_3(D) + y_4(D);
>   *   if (_1 >= x_3(D))
> @@ -4086,10 +4089,38 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
>   *   # _2 = PHI <255(2), _1(3)>
>   *   =>
>   *   <bb 4> [local count: 1073741824]:
> - *   _2 = .SAT_ADD (x_4(D), y_5(D));  */
> + *   _2 = .SAT_ADD (x_4(D), y_5(D));
> + *
> + * For signed integer:
> + *   _1 = x_5(D) ^ y_6(D);
> + *   _13 = x_5(D) + y_6(D);
> + *   _3 = x_5(D) ^ _13;
> + *   _2 = ~_1;
> + *   _7 = _2 & _3;
> + *   if (_7 < 0)
> + *     goto <bb 3>; [59.00%]
> + *   else
> + *     goto <bb 4>; [41.00%]
> + *   ;;    succ:       4
> + *   ;;                3
> + *   ;;   basic block 3, loop depth 0
> + *   ;;    pred:       2
> + *   _9 = x_5(D) < 0;
> + *   _10 = (long int) _9;
> + *   _11 = -_10;
> + *   _12 = _11 ^ 9223372036854775807;
> + *   ;;    succ:       4
> + *   ;;   basic block 4, loop depth 0
> + *   ;;    pred:       2
> + *   ;;                3
> + *   # _4 = PHI <_13(2), _12(3)>
> + *   =>
> + *   ;;   basic block 2, loop depth 0
> + *   ;;    pred:       ENTRY
> + *   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]  */
>
>  static void
> -match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
> +match_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
>  {
>    if (gimple_phi_num_args (phi) != 2)
>      return;
> @@ -4097,7 +4128,8 @@ match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
>    tree ops[2];
>    tree phi_result = gimple_phi_result (phi);
>
> -  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL))
> +  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL)
> +      || gimple_signed_integer_sat_add (phi_result, ops, NULL))
>      build_saturation_binary_arith_call (gsi, phi, IFN_SAT_ADD, phi_result,
>                                         ops[0], ops[1]);
>  }
> @@ -6097,7 +6129,7 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
>      gsi_next (&psi))
>      {
>        gimple_stmt_iterator gsi = gsi_after_labels (bb);
> -      match_unsigned_saturation_add (&gsi, psi.phi ());
> +      match_saturation_add (&gsi, psi.phi ());
>        match_unsigned_saturation_sub (&gsi, psi.phi ());
>      }
>
> --
> 2.43.0
>
diff mbox series

Patch

diff --git a/gcc/match.pd b/gcc/match.pd
index c9c8478d286..8b8a5dbcfe3 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3311,6 +3311,23 @@  DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   }
   (if (otype_precision < itype_precision && wi::eq_p (trunc_max, int_cst))))))
 
+/* Signed saturation add, case 1:
+   T sum = X + Y;
+   SAT_S_ADD = (X ^ Y) < 0
+     ? sum
+     : (sum ^ x) >= 0
+       ? sum
+       : x < 0 ? MIN : MAX;  */
+(match (signed_integer_sat_add @0 @1)
+ (cond^ (lt (bit_and:c (bit_xor:c @0 (convert?@2 (plus:c (convert? @0)
+							 (convert? @1))))
+		       (bit_not (bit_xor:c @0 @1)))
+	    integer_zerop)
+	(bit_xor:c (negate (convert (lt @0 integer_zerop))) max_value)
+	@2)
+ (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type)
+      && types_match (type, @0, @1))))
+
 /* x >  y  &&  x != XXX_MIN  -->  x > y
    x >  y  &&  x == XXX_MIN  -->  false . */
 (for eqne (eq ne)
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 8d96a4c964b..f39c88741a4 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -4023,6 +4023,8 @@  extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
 extern bool gimple_unsigned_integer_sat_sub (tree, tree*, tree (*)(tree));
 extern bool gimple_unsigned_integer_sat_trunc (tree, tree*, tree (*)(tree));
 
+extern bool gimple_signed_integer_sat_add (tree, tree*, tree (*)(tree));
+
 static void
 build_saturation_binary_arith_call (gimple_stmt_iterator *gsi, internal_fn fn,
 				    tree lhs, tree op_0, tree op_1)
@@ -4072,7 +4074,8 @@  match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
 }
 
 /*
- * Try to match saturation unsigned add with PHI.
+ * Try to match saturation add with PHI.
+ * For unsigned integer:
  *   <bb 2> :
  *   _1 = x_3(D) + y_4(D);
  *   if (_1 >= x_3(D))
@@ -4086,10 +4089,38 @@  match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
  *   # _2 = PHI <255(2), _1(3)>
  *   =>
  *   <bb 4> [local count: 1073741824]:
- *   _2 = .SAT_ADD (x_4(D), y_5(D));  */
+ *   _2 = .SAT_ADD (x_4(D), y_5(D));
+ *
+ * For signed integer:
+ *   _1 = x_5(D) ^ y_6(D);
+ *   _13 = x_5(D) + y_6(D);
+ *   _3 = x_5(D) ^ _13;
+ *   _2 = ~_1;
+ *   _7 = _2 & _3;
+ *   if (_7 < 0)
+ *     goto <bb 3>; [59.00%]
+ *   else
+ *     goto <bb 4>; [41.00%]
+ *   ;;    succ:       4
+ *   ;;                3
+ *   ;;   basic block 3, loop depth 0
+ *   ;;    pred:       2
+ *   _9 = x_5(D) < 0;
+ *   _10 = (long int) _9;
+ *   _11 = -_10;
+ *   _12 = _11 ^ 9223372036854775807;
+ *   ;;    succ:       4
+ *   ;;   basic block 4, loop depth 0
+ *   ;;    pred:       2
+ *   ;;                3
+ *   # _4 = PHI <_13(2), _12(3)>
+ *   =>
+ *   ;;   basic block 2, loop depth 0
+ *   ;;    pred:       ENTRY
+ *   _4 = .SAT_ADD (x_5(D), y_6(D)); [tail call]  */
 
 static void
-match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
+match_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
 {
   if (gimple_phi_num_args (phi) != 2)
     return;
@@ -4097,7 +4128,8 @@  match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gphi *phi)
   tree ops[2];
   tree phi_result = gimple_phi_result (phi);
 
-  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL))
+  if (gimple_unsigned_integer_sat_add (phi_result, ops, NULL)
+      || gimple_signed_integer_sat_add (phi_result, ops, NULL))
     build_saturation_binary_arith_call (gsi, phi, IFN_SAT_ADD, phi_result,
 					ops[0], ops[1]);
 }
@@ -6097,7 +6129,7 @@  math_opts_dom_walker::after_dom_children (basic_block bb)
     gsi_next (&psi))
     {
       gimple_stmt_iterator gsi = gsi_after_labels (bb);
-      match_unsigned_saturation_add (&gsi, psi.phi ());
+      match_saturation_add (&gsi, psi.phi ());
       match_unsigned_saturation_sub (&gsi, psi.phi ());
     }