[gcc r15-3122] Match: Support form 4 for unsigned integer .SAT_TRUNC

[Pan Li via Gcc-cvs]

https://gcc.gnu.org/g:07988874c340e575521473b01dc98c8a1b2886b5

commit r15-3122-g07988874c340e575521473b01dc98c8a1b2886b5
Author: Pan Li <pan2...@intel.com>
Date:   Tue Aug 20 15:44:38 2024 +0800

    Match: Support form 4 for unsigned integer .SAT_TRUNC
    
    This patch would like to support the form 4 of the unsigned integer
    .SAT_TRUNC. Aka below example:
    
    Form 4:
      #define DEF_SAT_U_TRUC_FMT_4(NT, WT)           \
      NT __attribute__((noinline))                   \
      sat_u_truc_##WT##_to_##NT##_fmt_4 (WT x)       \
      {                                              \
        bool not_overflow = x <= (WT)(NT)(-1);       \
        return ((NT)x) | (NT)((NT)not_overflow - 1); \
      }
    
    DEF_SAT_U_TRUC_FMT_4(uint32_t, uint64_t)
    
    Before this patch:
       4   │ __attribute__((noinline))
       5   │ uint8_t sat_u_truc_uint32_t_to_uint8_t_fmt_4 (uint32_t x)
       6   │ {
       7   │   _Bool not_overflow;
       8   │   unsigned char _1;
       9   │   unsigned char _2;
      10   │   unsigned char _3;
      11   │   uint8_t _6;
      12   │
      13   │ ;;   basic block 2, loop depth 0
      14   │ ;;    pred:       ENTRY
      15   │   not_overflow_5 = x_4(D) <= 255;
      16   │   _1 = (unsigned char) x_4(D);
      17   │   _2 = (unsigned char) not_overflow_5;
      18   │   _3 = _2 + 255;
      19   │   _6 = _1 | _3;
      20   │   return _6;
      21   │ ;;    succ:       EXIT
      22   │
      23   │ }
    
    After this patch:
       4   │ __attribute__((noinline))
       5   │ uint8_t sat_u_truc_uint32_t_to_uint8_t_fmt_4 (uint32_t x)
       6   │ {
       7   │   uint8_t _6;
       8   │
       9   │ ;;   basic block 2, loop depth 0
      10   │ ;;    pred:       ENTRY
      11   │   _6 = .SAT_TRUNC (x_4(D)); [tail call]
      12   │   return _6;
      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 form 4 for unsigned .SAT_TRUNC matching.
    
    Signed-off-by: Pan Li <pan2...@intel.com>

Diff:
---
 gcc/match.pd | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/gcc/match.pd b/gcc/match.pd
index 65a3aae22430..78f1957e8c78 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3325,6 +3325,24 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
   }
   (if (otype_precision < itype_precision && wi::eq_p (trunc_max, int_cst))))))
 
+/* Unsigned saturation truncate, case 3, sizeof (WT) > sizeof (NT).
+   SAT_U_TRUNC = (NT)X | ((NT)(X <= (WT)-1) + (NT)-1).  */
+(match (unsigned_integer_sat_trunc @0)
+ (bit_ior:c (plus:c (convert (le @0 INTEGER_CST@1)) INTEGER_CST@2)
+           (convert @0))
+ (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
+      && TYPE_UNSIGNED (TREE_TYPE (@0)))
+ (with
+  {
+   unsigned itype_precision = TYPE_PRECISION (TREE_TYPE (@0));
+   unsigned otype_precision = TYPE_PRECISION (type);
+   wide_int trunc_max = wi::mask (otype_precision, false, itype_precision);
+   wide_int max = wi::mask (otype_precision, false, otype_precision);
+   wide_int int_cst_1 = wi::to_wide (@1);
+   wide_int int_cst_2 = wi::to_wide (@2);
+  }
+  (if (wi::eq_p (trunc_max, int_cst_1) && wi::eq_p (max, int_cst_2))))))
+
 /* x >  y  &&  x != XXX_MIN  -->  x > y
    x >  y  &&  x == XXX_MIN  -->  false . */
 (for eqne (eq ne)