aarch64: Improve vector constant generation using SVE INDEX instruction [PR113328]
SVE's INDEX instruction can be used to populate vectors by values starting from
"base" and incremented by "step" for each subsequent value. We can take
advantage of it to generate vector constants if TARGET_SVE is available and the
base and step values are within [-16, 15].
For example, with the following function:
typedef int v4si __attribute__ ((vector_size (16)));
v4si
f_v4si (void)
{
return (v4si){ 0, 1, 2, 3 };
}
GCC currently generates:
f_v4si:
adrp x0, .LC4
ldr q0, [x0, #:lo12:.LC4]
ret
.LC4:
.word 0
.word 1
.word 2
.word 3
With this patch, we generate an INDEX instruction instead if TARGET_SVE is
available.
f_v4si:
index z0.s, #0, #1
ret
PR target/113328
gcc/ChangeLog:
* config/aarch64/aarch64.cc (aarch64_simd_valid_immediate): Improve
handling of some ADVSIMD vectors by using SVE's INDEX if TARGET_SVE is
available.
(aarch64_output_simd_mov_immediate): Likewise.
gcc/testsuite/ChangeLog:
* gcc.target/aarch64/sve/acle/general/dupq_1.c: Update test to use
SVE's INDEX instruction.
* gcc.target/aarch64/sve/acle/general/dupq_2.c: Likewise.
* gcc.target/aarch64/sve/acle/general/dupq_3.c: Likewise.
* gcc.target/aarch64/sve/acle/general/dupq_4.c: Likewise.
* gcc.target/aarch64/sve/vec_init_3.c: New test.
Signed-off-by: Pengxuan Zheng <quic_pzheng@quicinc.com>
6 files changed
