From: Pan Li <pan2...@intel.com>
This patch would like to add the middle-end presentation for the
saturation add. Aka set the result of add to the max when overflow.
It will take the pattern similar as below.
SAT_ADD (x, y) => (x + y) | (-(TYPE)((TYPE)(x + y) < x))
Take uint8_t as example, we will have:
* SAT_ADD (1, 254) => 255.
* SAT_ADD (1, 255) => 255.
* SAT_ADD (2, 255) => 255.
* SAT_ADD (255, 255) => 255.
Given below example for the unsigned scalar integer uint64_t:
uint64_t sat_add_u64 (uint64_t x, uint64_t y)
{
return (x + y) | (- (uint64_t)((uint64_t)(x + y) < x));
}
Before this patch:
uint64_t sat_add_uint64_t (uint64_t x, uint64_t y)
{
long unsigned int _1;
_Bool _2;
long unsigned int _3;
long unsigned int _4;
uint64_t _7;
long unsigned int _10;
__complex__ long unsigned int _11;
;; basic block 2, loop depth 0
;; pred: ENTRY
_11 = .ADD_OVERFLOW (x_5(D), y_6(D));
_1 = REALPART_EXPR <_11>;
_10 = IMAGPART_EXPR <_11>;
_2 = _10 != 0;
_3 = (long unsigned int) _2;
_4 = -_3;
_7 = _1 | _4;
return _7;
;; succ: EXIT
}
After this patch:
uint64_t sat_add_uint64_t (uint64_t x, uint64_t y)
{
uint64_t _7;
;; basic block 2, loop depth 0
;; pred: ENTRY
_7 = .SAT_ADD (x_5(D), y_6(D)); [tail call]
return _7;
;; succ: EXIT
}
The below tests are passed for this patch:
1. The riscv fully regression tests.
3. The x86 bootstrap tests.
4. The x86 fully regression tests.
PR target/51492
PR target/112600
gcc/ChangeLog:
* internal-fn.cc (commutative_binary_fn_p): Add type IFN_SAT_ADD
to the return true switch case(s).
* internal-fn.def (SAT_ADD): Add new signed optab SAT_ADD.
* match.pd: Add unsigned SAT_ADD match(es).
* optabs.def (OPTAB_NL): Remove fixed-point limitation for
us/ssadd.
* tree-ssa-math-opts.cc (gimple_unsigned_integer_sat_add): New
extern func decl generated in match.pd match.
(match_saturation_arith): New func impl to match the saturation arith.
(math_opts_dom_walker::after_dom_children): Try match saturation
arith when IOR expr.
Signed-off-by: Pan Li <pan2...@intel.com>
---
gcc/internal-fn.cc | 1 +
gcc/internal-fn.def | 2 ++
gcc/match.pd | 51 +++++++++++++++++++++++++++++++++++++++
gcc/optabs.def | 4 +--
gcc/tree-ssa-math-opts.cc | 32 ++++++++++++++++++++++++
5 files changed, 88 insertions(+), 2 deletions(-)
diff --git a/gcc/internal-fn.cc b/gcc/internal-fn.cc
index 0a7053c2286..73045ca8c8c 100644
--- a/gcc/internal-fn.cc
+++ b/gcc/internal-fn.cc
@@ -4202,6 +4202,7 @@ commutative_binary_fn_p (internal_fn fn)
case IFN_UBSAN_CHECK_MUL:
case IFN_ADD_OVERFLOW:
case IFN_MUL_OVERFLOW:
+ case IFN_SAT_ADD:
case IFN_VEC_WIDEN_PLUS:
case IFN_VEC_WIDEN_PLUS_LO:
case IFN_VEC_WIDEN_PLUS_HI:
diff --git a/gcc/internal-fn.def b/gcc/internal-fn.def
index 848bb9dbff3..25badbb86e5 100644
--- a/gcc/internal-fn.def
+++ b/gcc/internal-fn.def
@@ -275,6 +275,8 @@ DEF_INTERNAL_SIGNED_OPTAB_FN (MULHS, ECF_CONST |
ECF_NOTHROW, first,
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_COND_FN (ADD, ECF_CONST, add, binary)
DEF_INTERNAL_COND_FN (SUB, ECF_CONST, sub, binary)
DEF_INTERNAL_COND_FN (MUL, ECF_CONST, smul, binary)
diff --git a/gcc/match.pd b/gcc/match.pd
index 07e743ae464..0f9c34fa897 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3043,6 +3043,57 @@ DEFINE_INT_AND_FLOAT_ROUND_FN (RINT)
|| POINTER_TYPE_P (itype))
&& wi::eq_p (wi::to_wide (int_cst), wi::max_value (itype))))))
+/* Unsigned Saturation Add */
+(match (usadd_left_part_1 @0 @1)
+ (plus:c @0 @1)
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_UNSIGNED (TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@1)))))
+
+(match (usadd_left_part_2 @0 @1)
+ (realpart (IFN_ADD_OVERFLOW:c @0 @1))
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_UNSIGNED (TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@1)))))
+
+(match (usadd_right_part_1 @0 @1)
+ (negate (convert (lt (plus:c @0 @1) @0)))
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_UNSIGNED (TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@1)))))
+
+(match (usadd_right_part_1 @0 @1)
+ (negate (convert (gt @0 (plus:c @0 @1))))
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_UNSIGNED (TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@1)))))
+
+(match (usadd_right_part_2 @0 @1)
+ (negate (convert (ne (imagpart (IFN_ADD_OVERFLOW:c @0 @1)) integer_zerop)))
+ (if (INTEGRAL_TYPE_P (type)
+ && TYPE_UNSIGNED (TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@0))
+ && types_match (type, TREE_TYPE (@1)))))
+
+/* We cannot merge or overload usadd_left_part_1 and usadd_left_part_2
+ because the sub part of left_part_2 cannot work with right_part_1.
+ For example, left_part_2 pattern focus one .ADD_OVERFLOW but the
+ right_part_1 has nothing to do with .ADD_OVERFLOW. */
+
+/* Unsigned saturation add, case 1 (branchless):
+ SAT_U_ADD = (X + Y) | - ((X + Y) < X) or
+ SAT_U_ADD = (X + Y) | - (X > (X + Y)). */
+(match (unsigned_integer_sat_add @0 @1)
+ (bit_ior:c (usadd_left_part_1 @0 @1) (usadd_right_part_1 @0 @1)))
+
+/* Unsigned saturation add, case 2 (branchless with .ADD_OVERFLOW). */
+(match (unsigned_integer_sat_add @0 @1)
+ (bit_ior:c (usadd_left_part_2 @0 @1) (usadd_right_part_2 @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 ad14f9328b9..3f2cb46aff8 100644
--- a/gcc/optabs.def
+++ b/gcc/optabs.def
@@ -111,8 +111,8 @@ OPTAB_NX(add_optab, "add$F$a3")
OPTAB_NX(add_optab, "add$Q$a3")
OPTAB_VL(addv_optab, "addv$I$a3", PLUS, "add", '3', gen_intv_fp_libfunc)
OPTAB_VX(addv_optab, "add$F$a3")
-OPTAB_NL(ssadd_optab, "ssadd$Q$a3", SS_PLUS, "ssadd", '3',
gen_signed_fixed_libfunc)
-OPTAB_NL(usadd_optab, "usadd$Q$a3", US_PLUS, "usadd", '3',
gen_unsigned_fixed_libfunc)
+OPTAB_NL(ssadd_optab, "ssadd$a3", SS_PLUS, "ssadd", '3',
gen_signed_fixed_libfunc)
+OPTAB_NL(usadd_optab, "usadd$a3", US_PLUS, "usadd", '3',
gen_unsigned_fixed_libfunc)
OPTAB_NL(sub_optab, "sub$P$a3", MINUS, "sub", '3', gen_int_fp_fixed_libfunc)
OPTAB_NX(sub_optab, "sub$F$a3")
OPTAB_NX(sub_optab, "sub$Q$a3")
diff --git a/gcc/tree-ssa-math-opts.cc b/gcc/tree-ssa-math-opts.cc
index e8c804f09b7..62da1c5ee08 100644
--- a/gcc/tree-ssa-math-opts.cc
+++ b/gcc/tree-ssa-math-opts.cc
@@ -4086,6 +4086,36 @@ arith_overflow_check_p (gimple *stmt, gimple *cast_stmt,
gimple *&use_stmt,
return 0;
}
+extern bool gimple_unsigned_integer_sat_add (tree, tree*, tree (*)(tree));
+
+/*
+ * 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); */
+static void
+match_saturation_arith (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)
+ && 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);
+ }
+}
+
/* Recognize for unsigned x
x = y - z;
if (x > y)
@@ -6048,6 +6078,8 @@ math_opts_dom_walker::after_dom_children (basic_block bb)
break;
case BIT_IOR_EXPR:
+ match_saturation_arith (&gsi, as_a<gassign *> (stmt));
+ /* fall-through */
case BIT_XOR_EXPR:
match_uaddc_usubc (&gsi, stmt, code);
break;
--
2.34.1
