This patch makes try to eliminate using temporary pseudo for
'(minus:SI (const_int) (reg:SI))' if the addition of negative constant
value can be emitted in a single machine instruction.
/* example */
int test0(int x) {
return 1 - x;
}
int test1(int x) {
return 100 - x;
}
int test2(int x) {
return 25600 - x;
}
;; before
test0:
movi.n a9, 1
sub a2, a9, a2
ret.n
test1:
movi a9, 0x64
sub a2, a9, a2
ret.n
test2:
movi.n a9, 0x19
slli a9, a9, 10
sub a2, a9, a2
ret.n
;; after
test0:
addi.n a2, a2, -1
neg a2, a2
ret.n
test1:
addi a2, a2, -100
neg a2, a2
ret.n
test2:
addmi a2, a2, -0x6400
neg a2, a2
ret.n
gcc/ChangeLog:
* config/xtensa/xtensa-protos.h (xtensa_m1_or_1_thru_15):
New prototype.
* config/xtensa/xtensa.cc (xtensa_m1_or_1_thru_15):
New function.
* config/xtensa/constraints.md (O):
Change to use the above function.
* config/xtensa/xtensa.md (*subsi3_from_const):
New insn_and_split pattern.
---
gcc/config/xtensa/constraints.md | 2 +-
gcc/config/xtensa/xtensa-protos.h | 1 +
gcc/config/xtensa/xtensa.cc | 7 +++++++
gcc/config/xtensa/xtensa.md | 24 ++++++++++++++++++++++++
4 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/gcc/config/xtensa/constraints.md b/gcc/config/xtensa/constraints.md
index 53e4d0d8dd1..5cade1db8ff 100644
--- a/gcc/config/xtensa/constraints.md
+++ b/gcc/config/xtensa/constraints.md
@@ -108,7 +108,7 @@
(define_constraint "O"
"An integer constant that can be used in ADDI.N instructions."
(and (match_code "const_int")
- (match_test "ival == -1 || IN_RANGE (ival, 1, 15)")))
+ (match_test "xtensa_m1_or_1_thru_15 (ival)")))
(define_constraint "P"
"An integer constant that can be used as a mask value in an EXTUI
diff --git a/gcc/config/xtensa/xtensa-protos.h
b/gcc/config/xtensa/xtensa-protos.h
index 64cbf27c248..ec715b44e4d 100644
--- a/gcc/config/xtensa/xtensa-protos.h
+++ b/gcc/config/xtensa/xtensa-protos.h
@@ -27,6 +27,7 @@ extern bool xtensa_simm8x256 (HOST_WIDE_INT);
extern bool xtensa_simm12b (HOST_WIDE_INT);
extern bool xtensa_b4const_or_zero (HOST_WIDE_INT);
extern bool xtensa_b4constu (HOST_WIDE_INT);
+extern bool xtensa_m1_or_1_thru_15 (HOST_WIDE_INT);
extern bool xtensa_mask_immediate (HOST_WIDE_INT);
extern bool xtensa_mem_offset (unsigned, machine_mode);
diff --git a/gcc/config/xtensa/xtensa.cc b/gcc/config/xtensa/xtensa.cc
index e3af78cd228..46ab9f36b56 100644
--- a/gcc/config/xtensa/xtensa.cc
+++ b/gcc/config/xtensa/xtensa.cc
@@ -471,6 +471,13 @@ xtensa_b4constu (HOST_WIDE_INT v)
}
+bool
+xtensa_m1_or_1_thru_15 (HOST_WIDE_INT v)
+{
+ return v == -1 || IN_RANGE (v, 1, 15);
+}
+
+
bool
xtensa_mask_immediate (HOST_WIDE_INT v)
{
diff --git a/gcc/config/xtensa/xtensa.md b/gcc/config/xtensa/xtensa.md
index 11258125165..113b313026e 100644
--- a/gcc/config/xtensa/xtensa.md
+++ b/gcc/config/xtensa/xtensa.md
@@ -216,6 +216,30 @@
(set_attr "mode" "SI")
(set_attr "length" "3")])
+(define_insn_and_split "*subsi3_from_const"
+ [(set (match_operand:SI 0 "register_operand" "=a")
+ (minus:SI (match_operand:SI 1 "const_int_operand" "i")
+ (match_operand:SI 2 "register_operand" "r")))]
+ "xtensa_simm8 (-INTVAL (operands[1]))
+ || xtensa_simm8x256 (-INTVAL (operands[1]))"
+ "#"
+ "&& 1"
+ [(set (match_dup 0)
+ (plus:SI (match_dup 2)
+ (match_dup 1)))
+ (set (match_dup 0)
+ (neg:SI (match_dup 0)))]
+{
+ operands[1] = GEN_INT (-INTVAL (operands[1]));
+}
+ [(set_attr "type" "arith")
+ (set_attr "mode" "SI")
+ (set (attr "length")
+ (if_then_else (match_test "TARGET_DENSITY
+ && xtensa_m1_or_1_thru_15 (-INTVAL
(operands[1]))")
+ (const_int 5)
+ (const_int 6)))])
+
(define_insn "subsf3"
[(set (match_operand:SF 0 "register_operand" "=f")
(minus:SF (match_operand:SF 1 "register_operand" "f")
--
2.30.2
