From: xuli <xuli1@eswincomputing.com>
Date: Mon, 21 Oct 2024 04:08:46 +0000 (+0000)
Subject: Match: Support IMM=1 for unsigned scalar .SAT_SUB IMM form 1
X-Git-Tag: basepoints/gcc-16~5017
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=4e65e12a9a34d76f9a43fbc7ae32875a909ac708;p=thirdparty%2Fgcc.git

Match: Support IMM=1 for unsigned scalar .SAT_SUB IMM form 1

This patch would like to support .SAT_SUB when one of the op
is IMM = 1 of form1.

Form 1:
 #define DEF_SAT_U_SUB_IMM_FMT_1(T, IMM) \
 T __attribute__((noinline))             \
 sat_u_sub_imm##IMM##_##T##_fmt_1 (T y)  \
 {                                       \
   return IMM >= y ? IMM - y : 0;        \
 }

Take below form 1 as example:
DEF_SAT_U_SUB_IMM_FMT_1(uint8_t, 1)

Before this patch:
__attribute__((noinline))
uint8_t sat_u_sub_imm1_uint8_t_fmt_1 (uint8_t y)
{
  uint8_t _1;
  uint8_t _3;

  <bb 2> [local count: 1073741824]:
  if (y_2(D) <= 1)
    goto <bb 3>; [41.00%]
  else
    goto <bb 4>; [59.00%]

  <bb 3> [local count: 440234144]:
  _3 = y_2(D) ^ 1;

  <bb 4> [local count: 1073741824]:
  # _1 = PHI <0(2), _3(3)>
  return _1;

}

After this patch:
__attribute__((noinline))
uint8_t sat_u_sub_imm1_uint8_t_fmt_1 (uint8_t y)
{
  uint8_t _1;

;;   basic block 2, loop depth 0
;;    pred:       ENTRY
  _1 = .SAT_SUB (1, y_2(D)); [tail call]
  return _1;
;;    succ:       EXIT

}

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: Li Xu <xuli1@eswincomputing.com>
gcc/ChangeLog:

	* match.pd: Support IMM=1.
---

diff --git a/gcc/match.pd b/gcc/match.pd
index 362bcac291fd..0455dfa69937 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3360,6 +3360,13 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   }
   (if (wi::eq_p (c2, max) && wi::eq_p (c0_add_1, max))))))
 
+/* The boundary condition for case 9: IMM = 1  (branch with le):
+   SAT_U_SUB = IMM >= Y ? (IMM - Y) : 0.  */
+(match (unsigned_integer_sat_sub @0 @1)
+ (cond^ (le @1 integer_onep@0) (bit_xor @1 integer_onep@0) integer_zerop)
+ (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
+     && types_match (type, @1))))
+
 /* Unsigned saturation sub with op_1 imm, case 10:
    SAT_U_SUB = X > IMM  ? (X - IMM) : 0.
              = X >= IMM ? (X - IMM) : 0.  */