[PATCH v2 1/2] Match: Add form 3 for unsigned SAT_MUL

[pan2 . li]

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

This patch would like to try to match the the unsigned
SAT_MUL form 3, aka below:

  #define DEF_SAT_U_MUL_FMT_3(NT, WT)             \
  NT __attribute__((noinline))                    \
  sat_u_mul_##NT##_from_##WT##_fmt_3 (NT a, NT b) \
  {                                               \
    WT x = (WT)a * (WT)b;                         \
    if ((x >> sizeof(a) * 8) == 0)                \
      return (NT)x;                               \
    else                                          \
      return (NT)-1;                              \
  }

While WT is  T is uint16_t, uint32_t, uint64_t and uint128_t,
and NT is is uint8_t, uint16_t, uint32_t and uint64_t.

gcc/ChangeLog:

        * match.pd: Add form 3 for unsigned SAT_MUL.

Signed-off-by: Pan Li <pan2...@intel.com>
---
 gcc/match.pd | 27 ++++++++++++++++++++++++++-
 1 file changed, 26 insertions(+), 1 deletion(-)

diff --git a/gcc/match.pd b/gcc/match.pd
index 66e8a787449..b1d7a3a1b73 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3629,12 +3629,37 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
        if (__builtin_mul_overflow (X, Y, &result))
          return -1;
        else
-         return -(T)overflow_p | result;
+         return result;
       }
       while T can be uint8_t, uint16_t, uint32_t and uint64_t.  */
    (cond^ (ne (imagpart (IFN_MUL_OVERFLOW:c@2 @0 @1)) integer_zerop)
           integer_minus_onep (realpart @2))
    (if (types_match (type, @0, @1))))
+  (match (unsigned_integer_sat_mul @0 @1)
+   /* SAT_U_MUL (X, Y) = {
+       WT x = (WT)a * (WT)b;
+       if ((x >> sizeof(a) * 8) == 0)
+         return (T)x;
+       else
+         return (T)-1;
+      }
+      while WT is uint128_t, T is uint8_t, uint16_t, uint32_t or uint64_t.  */
+   (convert (cond^ (eq (rshift (mult:c@3 (convert @0) (convert @1))
+                              INTEGER_CST@2)
+                      integer_zerop)
+                  @3 INTEGER_CST@4))
+   (if (types_match (type, @0, @1))
+    (with
+     {
+      unsigned prec = TYPE_PRECISION (type);
+      unsigned widen_prec = TYPE_PRECISION (TREE_TYPE (@3));
+      wide_int c4 = wi::to_wide (@4);
+      wide_int max = wi::mask (prec, false, widen_prec);
+      bool c4_is_max_p = wi::eq_p (c4, max);
+      unsigned c2 = tree_to_uhwi (@2);
+      bool c2_is_type_precision_p = c2 == prec;
+     }
+     (if (widen_prec > prec && c2_is_type_precision_p && c4_is_max_p)))))
 )
 
 /* The boundary condition for case 10: IMM = 1:
-- 
2.43.0