This patch improves GCC’s vectorization of __builtin_popcount for aarch64 target
by adding popcount patterns for vector modes besides QImode, i.e., HImode,
SImode and DImode.
With this patch, we now generate the following for V8HI:
cnt v1.16b, v0.16b
uaddlp v2.8h, v1.16b
For V4HI, we generate:
cnt v1.8b, v0.8b
uaddlp v2.4h, v1.8b
For V4SI, we generate:
cnt v1.16b, v0.16b
uaddlp v2.8h, v1.16b
uaddlp v3.4s, v2.8h
For V4SI with TARGET_DOTPROD, we generate the following instead:
movi v0.4s, #0
movi v1.16b, #1
cnt v3.16b, v2.16b
udot v0.4s, v3.16b, v1.16b
For V2SI, we generate:
cnt v1.8b, v.8b
uaddlp v2.4h, v1.8b
uaddlp v3.2s, v2.4h
For V2SI with TARGET_DOTPROD, we generate the following instead:
movi v0.8b, #0
movi v1.8b, #1
cnt v3.8b, v2.8b
udot v0.2s, v3.8b, v1.8b
For V2DI, we generate:
cnt v1.16b, v.16b
uaddlp v2.8h, v1.16b
uaddlp v3.4s, v2.8h
uaddlp v4.2d, v3.4s
For V4SI with TARGET_DOTPROD, we generate the following instead:
movi v0.4s, #0
movi v1.16b, #1
cnt v3.16b, v2.16b
udot v0.4s, v3.16b, v1.16b
uaddlp v0.2d, v0.4s
PR target/113859
gcc/ChangeLog:
* config/aarch64/aarch64-simd.md (aarch64_<su>addlp<mode>): Rename to...
(@aarch64_<su>addlp<mode>): ... This.
(popcount<mode>2): New define_expand.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/popcnt-udot.c: New test.
* gcc.target/aarch64/popcnt-vec.c: New test.
Signed-off-by: Pengxuan Zheng <quic_pzh...@quicinc.com>
---
gcc/config/aarch64/aarch64-simd.md | 41 ++++++++++-
.../gcc.target/aarch64/popcnt-udot.c | 58 ++++++++++++++++
gcc/testsuite/gcc.target/aarch64/popcnt-vec.c | 69 +++++++++++++++++++
3 files changed, 167 insertions(+), 1 deletion(-)
create mode 100644 gcc/testsuite/gcc.target/aarch64/popcnt-udot.c
create mode 100644 gcc/testsuite/gcc.target/aarch64/popcnt-vec.c
diff --git a/gcc/config/aarch64/aarch64-simd.md
b/gcc/config/aarch64/aarch64-simd.md
index 01b084d8ccb..fd0c5e612b5 100644
--- a/gcc/config/aarch64/aarch64-simd.md
+++ b/gcc/config/aarch64/aarch64-simd.md
@@ -3461,7 +3461,7 @@ (define_insn
"*aarch64_<su>addlv<VDQV_L:mode>_ze<GPI:mode>"
[(set_attr "type" "neon_reduc_add<VDQV_L:q>")]
)
-(define_expand "aarch64_<su>addlp<mode>"
+(define_expand "@aarch64_<su>addlp<mode>"
[(set (match_operand:<VDBLW> 0 "register_operand")
(plus:<VDBLW>
(vec_select:<VDBLW>
@@ -3517,6 +3517,45 @@ (define_insn "popcount<mode>2<vczle><vczbe>"
[(set_attr "type" "neon_cnt<q>")]
)
+(define_expand "popcount<mode>2"
+ [(set (match_operand:VDQHSD 0 "register_operand")
+ (popcount:VDQHSD (match_operand:VDQHSD 1 "register_operand")))]
+ "TARGET_SIMD"
+ {
+ /* Generate a byte popcount. */
+ machine_mode mode = <bitsize> == 64 ? V8QImode : V16QImode;
+ rtx tmp = gen_reg_rtx (mode);
+ auto icode = optab_handler (popcount_optab, mode);
+ emit_insn (GEN_FCN (icode) (tmp, gen_lowpart (mode, operands[1])));
+
+ if (TARGET_DOTPROD
+ && (<VEL>mode == SImode || <VEL>mode == DImode))
+ {
+ /* For V4SI and V2SI, we can generate a UDOT with a 0 accumulator and a
+ 1 multiplicand. For V2DI, another UAADDLP is needed. */
+ rtx ones = force_reg (mode, CONST1_RTX (mode));
+ auto icode = optab_handler (udot_prod_optab, mode);
+ mode = <bitsize> == 64 ? V2SImode : V4SImode;
+ rtx dest = mode == <MODE>mode ? operands[0] : gen_reg_rtx (mode);
+ rtx zeros = force_reg (mode, CONST0_RTX (mode));
+ emit_insn (GEN_FCN (icode) (dest, tmp, ones, zeros));
+ tmp = dest;
+ }
+
+ /* Use a sequence of UADDLPs to accumulate the counts. Each step doubles
+ the element size and halves the number of elements. */
+ while (mode != <MODE>mode)
+ {
+ auto icode = code_for_aarch64_addlp (ZERO_EXTEND, GET_MODE (tmp));
+ mode = insn_data[icode].operand[0].mode;
+ rtx dest = mode == <MODE>mode ? operands[0] : gen_reg_rtx (mode);
+ emit_insn (GEN_FCN (icode) (dest, tmp));
+ tmp = dest;
+ }
+ DONE;
+ }
+)
+
;; 'across lanes' max and min ops.
;; Template for outputting a scalar, so we can create __builtins which can be
diff --git a/gcc/testsuite/gcc.target/aarch64/popcnt-udot.c
b/gcc/testsuite/gcc.target/aarch64/popcnt-udot.c
new file mode 100644
index 00000000000..f6a968dae95
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/popcnt-udot.c
@@ -0,0 +1,58 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -march=armv8.2-a+dotprod -fno-vect-cost-model
-fno-schedule-insns -fno-schedule-insns2" } */
+
+/*
+** bar:
+** movi v([0-9]+).16b, 0x1
+** movi v([0-9]+).4s, 0
+** ldr q([0-9]+), \[x0\]
+** cnt v([0-9]+).16b, v\3.16b
+** udot v\2.4s, v\4.16b, v\1.16b
+** str q\2, \[x1\]
+** ret
+*/
+void
+bar (unsigned int *__restrict b, unsigned int *__restrict d)
+{
+ d[0] = __builtin_popcount (b[0]);
+ d[1] = __builtin_popcount (b[1]);
+ d[2] = __builtin_popcount (b[2]);
+ d[3] = __builtin_popcount (b[3]);
+}
+
+/*
+** bar1:
+** movi v([0-9]+).8b, 0x1
+** movi v([0-9]+).2s, 0
+** ldr d([0-9]+), \[x0\]
+** cnt v([0-9]+).8b, v\3.8b
+** udot v\2.2s, v\4.8b, v\1.8b
+** str d\2, \[x1\]
+** ret
+*/
+void
+bar1 (unsigned int *__restrict b, unsigned int *__restrict d)
+{
+ d[0] = __builtin_popcount (b[0]);
+ d[1] = __builtin_popcount (b[1]);
+}
+
+/*
+** bar2:
+** movi v([0-9]+).16b, 0x1
+** movi v([0-9]+).4s, 0
+** ldr q([0-9]+), \[x0\]
+** cnt v([0-9]+).16b, v\3.16b
+** udot v\2.4s, v\4.16b, v\1.16b
+** uaddlp v\2.2d, v\2.4s
+** str q\2, \[x1\]
+** ret
+*/
+void
+bar2 (unsigned long long *__restrict b, unsigned long long *__restrict d)
+{
+ d[0] = __builtin_popcountll (b[0]);
+ d[1] = __builtin_popcountll (b[1]);
+}
+
+/* { dg-final { check-function-bodies "**" "" "" } } */
diff --git a/gcc/testsuite/gcc.target/aarch64/popcnt-vec.c
b/gcc/testsuite/gcc.target/aarch64/popcnt-vec.c
new file mode 100644
index 00000000000..b3cb8def2d5
--- /dev/null
+++ b/gcc/testsuite/gcc.target/aarch64/popcnt-vec.c
@@ -0,0 +1,69 @@
+/* { dg-do compile } */
+/* { dg-options "-O2 -fno-vect-cost-model" } */
+
+/* This function should produce cnt v.16b. */
+void
+bar (unsigned char *__restrict b, unsigned char *__restrict d)
+{
+ for (int i = 0; i < 1024; i++)
+ d[i] = __builtin_popcount (b[i]);
+}
+
+/* This function should produce cnt v.16b and uaddlp (Add Long Pairwise). */
+void
+bar1 (unsigned short *__restrict b, unsigned short *__restrict d)
+{
+ for (int i = 0; i < 1024; i++)
+ d[i] = __builtin_popcount (b[i]);
+}
+
+/* This function should produce cnt v.16b and 2 uaddlp (Add Long Pairwise). */
+void
+bar2 (unsigned int *__restrict b, unsigned int *__restrict d)
+{
+ for (int i = 0; i < 1024; i++)
+ d[i] = __builtin_popcount (b[i]);
+}
+
+/* This function should produce cnt v.16b and 3 uaddlp (Add Long Pairwise). */
+void
+bar3 (unsigned long long *__restrict b, unsigned long long *__restrict d)
+{
+ for (int i = 0; i < 1024; i++)
+ d[i] = __builtin_popcountll (b[i]);
+}
+
+/* SLP
+ This function should produce cnt v.8b and uaddlp (Add Long Pairwise). */
+void
+bar4 (unsigned short *__restrict b, unsigned short *__restrict d)
+{
+ d[0] = __builtin_popcount (b[0]);
+ d[1] = __builtin_popcount (b[1]);
+ d[2] = __builtin_popcount (b[2]);
+ d[3] = __builtin_popcount (b[3]);
+}
+
+/* SLP
+ This function should produce cnt v.8b and 2 uaddlp (Add Long Pairwise). */
+void
+bar5 (unsigned int *__restrict b, unsigned int *__restrict d)
+{
+ d[0] = __builtin_popcount (b[0]);
+ d[1] = __builtin_popcount (b[1]);
+}
+
+/* SLP
+ This function should produce cnt v.16b and 3 uaddlp (Add Long Pairwise). */
+void
+bar6 (unsigned long long *__restrict b, unsigned long long *__restrict d)
+{
+ d[0] = __builtin_popcountll (b[0]);
+ d[1] = __builtin_popcountll (b[1]);
+}
+
+/* { dg-final { scan-assembler-not {\tbl\tpopcount} } } */
+/* { dg-final { scan-assembler-times {cnt\t} 7 } } */
+/* { dg-final { scan-assembler-times {uaddlp\t} 12 } } */
+/* { dg-final { scan-assembler-times {ldr\tq} 5 } } */
+/* { dg-final { scan-assembler-times {ldr\td} 2 } } */
--
2.17.1
