https://gcc.gnu.org/g:fe5f652bab420eb372645281f7fe3e5aa1534d01
commit r15-3241-gfe5f652bab420eb372645281f7fe3e5aa1534d01
Author: Pan Li <pan2...@intel.com>
Date: Mon Aug 26 10:11:38 2024 +0800
Match: Support form 1 for scalar signed integer .SAT_ADD
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, UT, MIN, MAX) \
T __attribute__((noinline)) \
sat_s_add_##T##_fmt_1 (T x, T y) \
{ \
T sum = (UT)x + (UT)y; \
return (x ^ y) < 0 \
? sum \
: (sum ^ x) >= 0 \
? sum \
: x < 0 ? MIN : MAX; \
}
DEF_SAT_S_ADD_FMT_1(int64_t, uint64_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 unsigned int x.0_1;
9 │ long unsigned int y.1_2;
10 │ long unsigned int _3;
11 │ long int _4;
12 │ long int _5;
13 │ int64_t _6;
14 │ _Bool _11;
15 │ long int _12;
16 │ long int _13;
17 │ long int _14;
18 │ long int _16;
19 │ long int _17;
20 │
21 │ ;; basic block 2, loop depth 0
22 │ ;; pred: ENTRY
23 │ x.0_1 = (long unsigned int) x_7(D);
24 │ y.1_2 = (long unsigned int) y_8(D);
25 │ _3 = x.0_1 + y.1_2;
26 │ sum_9 = (int64_t) _3;
27 │ _4 = x_7(D) ^ y_8(D);
28 │ _5 = x_7(D) ^ sum_9;
29 │ _17 = ~_4;
30 │ _16 = _5 & _17;
31 │ if (_16 < 0)
32 │ goto <bb 3>; [41.00%]
33 │ else
34 │ goto <bb 4>; [59.00%]
35 │ ;; succ: 3
36 │ ;; 4
37 │
38 │ ;; basic block 3, loop depth 0
39 │ ;; pred: 2
40 │ _11 = x_7(D) < 0;
41 │ _12 = (long int) _11;
42 │ _13 = -_12;
43 │ _14 = _13 ^ 9223372036854775807;
44 │ ;; succ: 4
45 │
46 │ ;; basic block 4, loop depth 0
47 │ ;; pred: 2
48 │ ;; 3
49 │ # _6 = PHI <sum_9(2), _14(3)>
50 │ return _6;
51 │ ;; succ: EXIT
52 │
53 │ }
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...@intel.com>
Diff:
---
gcc/match.pd | 15 +++++++++++++++
gcc/tree-ssa-math-opts.cc | 35 ++++++++++++++++++++++++++++++-----
2 files changed, 45 insertions(+), 5 deletions(-)
diff --git a/gcc/match.pd b/gcc/match.pd
index 5ee60963c904..be211535a49f 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3192,6 +3192,21 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
&& types_match (type, @0) && int_fits_type_p (@1, type))))
+/* Signed saturation add, case 1:
+ T sum = (T)((UT)X + (UT)Y)
+ SAT_S_ADD = (X ^ sum) & !(X ^ Y) < 0 ? (-(T)(X < 0) ^ MAX) : sum;
+
+ The T and UT are type pair like T=int8_t, UT=uint8_t. */
+(match (signed_integer_sat_add @0 @1)
+ (cond^ (lt (bit_and:c (bit_xor:c @0 (nop_convert@2 (plus (nop_convert @0)
+ (nop_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))))
+
/* Unsigned saturation sub, case 1 (branch with gt):
SAT_U_SUB = X > Y ? X - Y : 0 */
(match (unsigned_integer_sat_sub @0 @1)
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 8d96a4c964b3..3c93fca5b538 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 +4089,31 @@ 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:
+ * x.0_1 = (long unsigned int) x_7(D);
+ * y.1_2 = (long unsigned int) y_8(D);
+ * _3 = x.0_1 + y.1_2;
+ * sum_9 = (int64_t) _3;
+ * _4 = x_7(D) ^ y_8(D);
+ * _5 = x_7(D) ^ sum_9;
+ * _15 = ~_4;
+ * _16 = _5 & _15;
+ * if (_16 < 0)
+ * goto <bb 3>; [41.00%]
+ * else
+ * goto <bb 4>; [59.00%]
+ * _11 = x_7(D) < 0;
+ * _12 = (long int) _11;
+ * _13 = -_12;
+ * _14 = _13 ^ 9223372036854775807;
+ * # _6 = PHI <_14(3), sum_9(2)>
+ * =>
+ * _6 = .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 +4121,8 @@ 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 +6122,7 @@ 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 ());
}
