Kindly ping, almost the same but for subtract.
Pan
-----Original Message-----
From: Li, Pan2 <pan2...@intel.com>
Sent: Tuesday, May 28, 2024 4:30 PM
To: gcc-patches@gcc.gnu.org
Cc: juzhe.zh...@rivai.ai; kito.ch...@gmail.com; tamar.christ...@arm.com;
richard.guent...@gmail.com; Li, Pan2 <pan2...@intel.com>
Subject: [PATCH v1] Internal-fn: Support new IFN SAT_SUB for unsigned scalar int
From: Pan Li <pan2...@intel.com>
This patch would like to add the middle-end presentation for the
saturation sub. Aka set the result of add to the min when downflow.
It will take the pattern similar as below.
SAT_SUB (x, y) => (x - y) & (-(TYPE)(x >= y));
For example for uint8_t, we have
* SAT_SUB (255, 0) => 255
* SAT_SUB (1, 2) => 0
* SAT_SUB (254, 255) => 0
* SAT_SUB (0, 255) => 0
Given below SAT_SUB for uint64
uint64_t sat_sub_u64 (uint64_t x, uint64_t y)
{
return (x + y) & (- (uint64_t)((x >= y)));
}
Before this patch:
uint64_t sat_sub_u_0_uint64_t (uint64_t x, uint64_t y)
{
_Bool _1;
long unsigned int _3;
uint64_t _6;
;; basic block 2, loop depth 0
;; pred: ENTRY
_1 = x_4(D) >= y_5(D);
_3 = x_4(D) - y_5(D);
_6 = _1 ? _3 : 0;
return _6;
;; succ: EXIT
}
After this patch:
uint64_t sat_sub_u_0_uint64_t (uint64_t x, uint64_t y)
{
uint64_t _6;
;; basic block 2, loop depth 0
;; pred: ENTRY
_6 = .SAT_SUB (x_4(D), y_5(D)); [tail call]
return _6;
;; succ: EXIT
}
The below tests are running for this patch:
*. The riscv fully regression tests.
*. The x86 bootstrap tests.
*. The x86 fully regression tests.
PR target/51492
PR target/112600
gcc/ChangeLog:
* internal-fn.def (SAT_SUB): Add new IFN define for SAT_SUB.
* match.pd: Add new match for SAT_SUB.
* optabs.def (OPTAB_NL): Remove fixed-point for ussub/ssub.
* tree-ssa-math-opts.cc (gimple_unsigned_integer_sat_sub): Add
new decl for generated in match.pd.
(build_saturation_binary_arith_call): Add new helper function
to build the gimple call to binary SAT alu.
(match_saturation_arith): Rename from.
(match_unsigned_saturation_add): Rename to.
(match_unsigned_saturation_sub): Add new func to match the
unsigned sat sub.
(math_opts_dom_walker::after_dom_children): Add SAT_SUB matching
try when COND_EXPR.
Signed-off-by: Pan Li <pan2...@intel.com>
---
gcc/internal-fn.def | 1 +
gcc/match.pd | 14 ++++++++
gcc/optabs.def | 4 +--
gcc/tree-ssa-math-opts.cc | 67 +++++++++++++++++++++++++++------------
4 files changed, 64 insertions(+), 22 deletions(-)
diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index 25badbb86e5..24539716e5b 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -276,6 +276,7 @@ DEF_INTERNAL_SIGNED_OPTAB_FN (MULHRS, ECF_CONST |
ECF_NOTHROW, first,
smulhrs, umulhrs, binary)
DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_ADD, ECF_CONST, first, ssadd, usadd, binary)
+DEF_INTERNAL_SIGNED_OPTAB_FN (SAT_SUB, ECF_CONST, first, sssub, ussub, binary)
DEF_INTERNAL_COND_FN (ADD, ECF_CONST, add, binary)
DEF_INTERNAL_COND_FN (SUB, ECF_CONST, sub, binary)
diff --git a/gcc/match.pd b/gcc/match.pd
index 024e3350465..3e334533ff8 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3086,6 +3086,20 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
(match (unsigned_integer_sat_add @0 @1)
(bit_ior:c (usadd_left_part_2 @0 @1) (usadd_right_part_2 @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)
+ (cond (gt @0 @1) (minus @0 @1) integer_zerop)
+ (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
+ && types_match (type, @0, @1))))
+
+/* Unsigned saturation sub, case 2 (branch with ge):
+ SAT_U_SUB = X >= Y ? X - Y : 0. */
+(match (unsigned_integer_sat_sub @0 @1)
+ (cond (ge @0 @1) (minus @0 @1) integer_zerop)
+ (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
+ && types_match (type, @0, @1))))
+
/* x > y && x != XXX_MIN --> x > y
x > y && x == XXX_MIN --> false . */
(for eqne (eq ne)
diff --git a/gcc/optabs.def b/gcc/optabs.def
index 3f2cb46aff8..bc2611abdc2 100644
--- a/gcc/optabs.def
+++ b/gcc/optabs.def
@@ -118,8 +118,8 @@ OPTAB_NX(sub_optab, "sub$F$a3")
OPTAB_NX(sub_optab, "sub$Q$a3")
OPTAB_VL(subv_optab, "subv$I$a3", MINUS, "sub", '3', gen_intv_fp_libfunc)
OPTAB_VX(subv_optab, "sub$F$a3")
-OPTAB_NL(sssub_optab, "sssub$Q$a3", SS_MINUS, "sssub", '3',
gen_signed_fixed_libfunc)
-OPTAB_NL(ussub_optab, "ussub$Q$a3", US_MINUS, "ussub", '3',
gen_unsigned_fixed_libfunc)
+OPTAB_NL(sssub_optab, "sssub$a3", SS_MINUS, "sssub", '3',
gen_signed_fixed_libfunc)
+OPTAB_NL(ussub_optab, "ussub$a3", US_MINUS, "ussub", '3',
gen_unsigned_fixed_libfunc)
OPTAB_NL(smul_optab, "mul$Q$a3", MULT, "mul", '3', gen_int_fp_fixed_libfunc)
OPTAB_NX(smul_optab, "mul$P$a3")
OPTAB_NX(smul_optab, "mul$F$a3")
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index 62da1c5ee08..4717302b728 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -4087,33 +4087,56 @@ arith_overflow_check_p (gimple *stmt, gimple
*cast_stmt, gimple *&use_stmt,
}
extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
+extern bool gimple_unsigned_integer_sat_sub (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)
+{
+ if (direct_internal_fn_supported_p (fn, TREE_TYPE (lhs), OPTIMIZE_FOR_BOTH))
+ {
+ gcall *call = gimple_build_call_internal (fn, 2, op_0, op_1);
+ gimple_call_set_lhs (call, lhs);
+ gsi_replace (gsi, call, /* update_eh_info */ true);
+ }
+}
/*
- * Try to match saturation arith pattern(s).
- * 1. SAT_ADD (unsigned)
- * _7 = _4 + _6;
- * _8 = _4 > _7;
- * _9 = (long unsigned int) _8;
- * _10 = -_9;
- * _12 = _7 | _10;
- * =>
- * _12 = .SAT_ADD (_4, _6); */
+ * Try to match saturation unsigned add.
+ * _7 = _4 + _6;
+ * _8 = _4 > _7;
+ * _9 = (long unsigned int) _8;
+ * _10 = -_9;
+ * _12 = _7 | _10;
+ * =>
+ * _12 = .SAT_ADD (_4, _6); */
+
static void
-match_saturation_arith (gimple_stmt_iterator *gsi, gassign *stmt)
+match_unsigned_saturation_add (gimple_stmt_iterator *gsi, gassign *stmt)
{
- gcall *call = NULL;
+ tree ops[2];
+ tree lhs = gimple_assign_lhs (stmt);
+ if (gimple_unsigned_integer_sat_add (lhs, ops, NULL))
+ build_saturation_binary_arith_call (gsi, IFN_SAT_ADD, lhs, ops[0], ops[1]);
+}
+
+/*
+ * Try to match saturation unsigned sub.
+ * _1 = _4 >= _5;
+ * _3 = _4 - _5;
+ * _6 = _1 ? _3 : 0;
+ * =>
+ * _6 = .SAT_SUB (_4, _5); */
+
+static void
+match_unsigned_saturation_sub (gimple_stmt_iterator *gsi, gassign *stmt)
+{
tree ops[2];
tree lhs = gimple_assign_lhs (stmt);
- if (gimple_unsigned_integer_sat_add (lhs, ops, NULL)
- && direct_internal_fn_supported_p (IFN_SAT_ADD, TREE_TYPE (lhs),
- OPTIMIZE_FOR_BOTH))
- {
- call = gimple_build_call_internal (IFN_SAT_ADD, 2, ops[0], ops[1]);
- gimple_call_set_lhs (call, lhs);
- gsi_replace (gsi, call, true);
- }
+ if (gimple_unsigned_integer_sat_sub (lhs, ops, NULL))
+ build_saturation_binary_arith_call (gsi, IFN_SAT_SUB, lhs, ops[0], ops[1]);
}
/* Recognize for unsigned x
@@ -6078,7 +6101,7 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
break;
case BIT_IOR_EXPR:
- match_saturation_arith (&gsi, as_a<gassign *> (stmt));
+ match_unsigned_saturation_add (&gsi, as_a<gassign *> (stmt));
/* fall-through */
case BIT_XOR_EXPR:
match_uaddc_usubc (&gsi, stmt, code);
@@ -6089,6 +6112,10 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
match_single_bit_test (&gsi, stmt);
break;
+ case COND_EXPR:
+ match_unsigned_saturation_sub (&gsi, as_a<gassign *> (stmt));
+ break;
+
default:;
}
}
--
2.34.1
