From: Pan Li <[email protected]>
There are sorts of forms for the unsigned SAT_ADD. Some of them are
complicated while others are cheap. This patch would like to simplify
the complicated form into the cheap ones. For example as below:
>From the form 4 (branch):
SAT_U_ADD = (X + Y) < x ? -1 : (X + Y).
To (branchless):
SAT_U_ADD = (X + Y) | - ((X + Y) < X).
#define T uint8_t
T sat_add_u_1 (T x, T y)
{
return (T)(x + y) < x ? -1 : (x + y);
}
Before this patch:
1 │ uint8_t sat_add_u_1 (uint8_t x, uint8_t y)
2 │ {
3 │ uint8_t D.2809;
4 │
5 │ _1 = x + y;
6 │ if (x <= _1) goto <D.2810>; else goto <D.2811>;
7 │ <D.2810>:
8 │ D.2809 = x + y;
9 │ goto <D.2812>;
10 │ <D.2811>:
11 │ D.2809 = 255;
12 │ <D.2812>:
13 │ return D.2809;
14 │ }
After this patch:
1 │ uint8_t sat_add_u_1 (uint8_t x, uint8_t y)
2 │ {
3 │ uint8_t D.2809;
4 │
5 │ _1 = x + y;
6 │ _2 = x + y;
7 │ _3 = x > _2;
8 │ _4 = (unsigned char) _3;
9 │ _5 = -_4;
10 │ D.2809 = _1 | _5;
11 │ return D.2809;
12 │ }
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: Remove unsigned branch form 4 for SAT_ADD, and
add simplify to branchless instead.
gcc/testsuite/ChangeLog:
* gcc.dg/sat_arith_simplify.h: New test.
* gcc.dg/sat_u_add-simplify-2-u16.c: New test.
* gcc.dg/sat_u_add-simplify-2-u32.c: New test.
* gcc.dg/sat_u_add-simplify-2-u64.c: New test.
* gcc.dg/sat_u_add-simplify-2-u8.c: New test.
Signed-off-by: Pan Li <[email protected]>
---
gcc/match.pd | 23 +++++++++----------
gcc/testsuite/gcc.dg/sat_arith_simplify.h | 10 ++++++++
.../gcc.dg/sat_u_add-simplify-2-u16.c | 11 +++++++++
.../gcc.dg/sat_u_add-simplify-2-u32.c | 11 +++++++++
.../gcc.dg/sat_u_add-simplify-2-u64.c | 11 +++++++++
.../gcc.dg/sat_u_add-simplify-2-u8.c | 11 +++++++++
6 files changed, 65 insertions(+), 12 deletions(-)
create mode 100644 gcc/testsuite/gcc.dg/sat_arith_simplify.h
create mode 100644 gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u16.c
create mode 100644 gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u32.c
create mode 100644 gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u64.c
create mode 100644 gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u8.c
diff --git a/gcc/match.pd b/gcc/match.pd
index c851ac56e37..8425d7c4f20 100644
--- a/gcc/match.pd
+++ b/gcc/match.pd
@@ -3146,18 +3146,17 @@ 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)))
-/* Simplify SAT_U_ADD to the cheap form
- From: SAT_U_ADD = (X + Y) >= x ? (X + Y) : -1.
- To: SAT_U_ADD = (X + Y) | - ((X + Y) < X). */
-(simplify (cond (ge (plus:c@2 @0 @1) @0) @2 integer_minus_onep)
- (if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type)
- && types_match (type, @0, @1))
- (bit_ior @2 (negate (convert (lt @2 @0))))))
-
-/* Unsigned saturation add, case 4 (branch with lt):
- SAT_U_ADD = (X + Y) < x ? -1 : (X + Y). */
-(match (unsigned_integer_sat_add @0 @1)
- (cond^ (lt (usadd_left_part_1@2 @0 @1) @0) integer_minus_onep @2))
+/* Simplify sorts of SAT_U_ADD forms to the cheap one.
+ The cheap form: SAT_U_ADD = (X + Y) | - ((X + Y) < X). */
+(if (INTEGRAL_TYPE_P (type) && TYPE_UNSIGNED (type))
+ /* From SAT_U_ADD = (X + Y) >= x ? (X + Y) : -1. */
+ (simplify (cond (ge (plus:c@2 @0 @1) @0) @2 integer_minus_onep)
+ (if (types_match (type, @0, @1))
+ (bit_ior (plus@2 @0 @1) (negate (convert (lt @2 @0))))))
+ /* From SAT_U_ADD = (X + Y) < x ? -1 : (X + Y). */
+ (simplify (cond (lt (plus:c@2 @0 @1) @0) integer_minus_onep @2)
+ (if (types_match (type, @0, @1))
+ (bit_ior (plus@2 @0 @1) (negate (convert (lt @2 @0)))))))
/* Unsigned saturation add, case 5 (branch with eq .ADD_OVERFLOW):
SAT_U_ADD = REALPART_EXPR <.ADD_OVERFLOW> == 0 ? .ADD_OVERFLOW : -1. */
diff --git a/gcc/testsuite/gcc.dg/sat_arith_simplify.h
b/gcc/testsuite/gcc.dg/sat_arith_simplify.h
new file mode 100644
index 00000000000..46ac00426b2
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/sat_arith_simplify.h
@@ -0,0 +1,10 @@
+#ifndef HAVE_DEFINED_SAT_ARITH_SIMPLIFY_H
+#define HAVE_DEFINED_SAT_ARITH_SIMPLIFY_H
+
+#define DEF_SAT_U_ADD_2(T) \
+T sat_u_add_##T##_2 (T x, T y) \
+{ \
+ return (T)(x + y) < x ? -1 : (x + y); \
+}
+
+#endif
diff --git a/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u16.c
b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u16.c
new file mode 100644
index 00000000000..b170b35096c
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u16.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-gimple-details" } */
+
+#include <stdint.h>
+#include "sat_arith_simplify.h"
+
+DEF_SAT_U_ADD_2 (uint16_t)
+
+/* { dg-final { scan-tree-dump-not " if " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " else " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " goto " "gimple" } } */
diff --git a/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u32.c
b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u32.c
new file mode 100644
index 00000000000..8830ed7b878
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u32.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-gimple-details" } */
+
+#include <stdint.h>
+#include "sat_arith_simplify.h"
+
+DEF_SAT_U_ADD_2 (uint32_t)
+
+/* { dg-final { scan-tree-dump-not " if " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " else " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " goto " "gimple" } } */
diff --git a/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u64.c
b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u64.c
new file mode 100644
index 00000000000..76c4d4bddaa
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u64.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-gimple-details" } */
+
+#include <stdint.h>
+#include "sat_arith_simplify.h"
+
+DEF_SAT_U_ADD_2 (uint64_t)
+
+/* { dg-final { scan-tree-dump-not " if " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " else " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " goto " "gimple" } } */
diff --git a/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u8.c
b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u8.c
new file mode 100644
index 00000000000..b034b8eedb1
--- /dev/null
+++ b/gcc/testsuite/gcc.dg/sat_u_add-simplify-2-u8.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fdump-tree-gimple-details" } */
+
+#include <stdint.h>
+#include "sat_arith_simplify.h"
+
+DEF_SAT_U_ADD_2 (uint8_t)
+
+/* { dg-final { scan-tree-dump-not " if " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " else " "gimple" } } */
+/* { dg-final { scan-tree-dump-not " goto " "gimple" } } */
--
2.43.0
