Match: Support for signed scalar SAT_ADD IMM form 2

This patch would like to support signed scalar SAT_ADD IMM form 2

Form2:
T __attribute__((noinline))                                  \
sat_s_add_imm_##T##_fmt_2##_##INDEX (T x)                    \
{                                                            \
  T sum = (T)((UT)x + (UT)IMM);                                   \
  return ((x ^ sum) < 0 && (x ^ IMM) >= 0) ?                 \
    (-(T)(x < 0) ^ MAX) : sum;                         \
}

Take below form1 as example:
DEF_SAT_S_ADD_IMM_FMT_2(0, int8_t, uint8_t, 9, INT8_MIN, INT8_MAX)

Before this patch:
__attribute__((noinline))
int8_t sat_s_add_imm_int8_t_fmt_2_0 (int8_t x)
{
  int8_t sum;
  unsigned char x.0_1;
  unsigned char _2;
  signed char _3;
  signed char _4;
  _Bool _5;
  signed char _6;
  int8_t _7;
  int8_t _10;
  signed char _11;
  signed char _13;
  signed char _14;

  <bb 2> [local count: 1073741822]:
  x.0_1 = (unsigned char) x_8(D);
  _2 = x.0_1 + 9;
  sum_9 = (int8_t) _2;
  _3 = x_8(D) ^ sum_9;
  _4 = x_8(D) ^ 9;
  _13 = ~_3;
  _14 = _4 | _13;
  if (_14 >= 0)
    goto <bb 3>; [59.00%]
  else
    goto <bb 4>; [41.00%]

  <bb 3> [local count: 259738146]:
  _5 = x_8(D) < 0;
  _11 = (signed char) _5;
  _6 = -_11;
  _10 = _6 ^ 127;

  <bb 4> [local count: 1073741824]:
  # _7 = PHI <sum_9(2), _10(3)>
  return _7;

}

After this patch:
__attribute__((noinline))
int8_t sat_s_add_imm_int8_t_fmt_2_0 (int8_t x)
{
  int8_t _7;

  <bb 2> [local count: 1073741824]:
  _7 = .SAT_ADD (x_8(D), 9); [tail call]
  return _7;

}

The below test suites are passed for this patch:
1. The rv64gcv fully regression tests.
2. The x86 bootstrap tests.
3. The x86 fully regression tests.

Signed-off-by: Ciyan Pan <panciyan@eswincomputing.com>
gcc/ChangeLog:

	* match.pd: Add signed scalar SAT_ADD IMM form2 matching.

diff --git a/gcc/match.pd b/gcc/match.pd
index f4416d9172c4f98dee5c5256133310d0f472aae4..10c2b97f494ecc741aa607ad253ee22e3184cb12 100644 (file)
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3500,7 +3500,18 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
      wide_int c2 = wi::to_wide (@2);
      wide_int sum = wi::add (c1, c2);
     }
-    (if (wi::eq_p (sum, wi::max_value (precision, SIGNED)))))))
+    (if (wi::eq_p (sum, wi::max_value (precision, SIGNED))))))
+
+(match (signed_integer_sat_add @0 @1)
+  /* T SUM = (T)((UT)X + (UT)IMM)
+     SAT_S_ADD = (X ^ SUM) < 0 && (X ^ IMM) >= 0 ? (-(T)(X < 0) ^ MAX) : SUM  */
+   (cond^ (ge (bit_ior:c (bit_xor:c @0 INTEGER_CST@1)
+                       (bit_not (bit_xor:c @0 (nop_convert@2 (plus (nop_convert @0)
+                       INTEGER_CST@3)))))
+                   integer_zerop)
+           (signed_integer_sat_val @0)
+           @2)
+   (if (wi::eq_p (wi::to_wide (@1), wi::to_wide (@3))))))
 
 /* Saturation sub for signed integer.  */
 (if (INTEGRAL_TYPE_P (type) && !TYPE_UNSIGNED (type))