From: zhongjuzhe <juzhe.zh...@rivai.ai>
Hello. This patch is preparing for following RVV support.
Both ARM SVE and RVV (RISC-V 'V' Extension) support length-agnostic vector.
The minimum vector length of ARM SVE is 128-bit and the runtime invariant of
ARM SVE is always 128-bit blocks.
However, the minimum vector length of RVV can be 32bit in 'Zve32*'
sub-extension and 64bit in 'Zve*' sub-extension.
So I define the machine_mode as follows:
VECTOR_MODE_WITH_PREFIX (VNx, INT, DI, 1, 0);
ADJUST_NUNITS (MODE, riscv_vector_chunks);
The riscv_vector_chunks = poly_uint16 (1, 1)
The compilation is failed for the stepped vector test:
(const_vector:VNx1DI repeat [
(const_int 8 [0x8])
(const_int 7 [0x7])
])
I understand for stepped vector should always have aleast 2 elements and
stepped vector initialization is common
for VLA (vector-lengthe agnostic) auto-vectorization. It makes sense that
report fail for stepped vector of poly_uint16 (1, 1).
machine mode with nunits = poly_uint16 (1, 1) needs to implemented in
intrinsics. And I would like to enable RVV auto-vectorization
with vector mode only nunits is larger than poly_uint16 (2, 2) in RISC-V
backend. I think it will not create issue if we define
vector mode with nunits = poly_uint16 (1, 1). Feel free to correct me or offer
me some other better solutions. Thanks!
gcc/ChangeLog:
* simplify-rtx.cc (test_vector_subregs_fore_back): skip test for
poly_uint16 (1, 1).
---
gcc/simplify-rtx.cc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/gcc/simplify-rtx.cc b/gcc/simplify-rtx.cc
index 7d09bf7103d..61e0dfa00d0 100644
--- a/gcc/simplify-rtx.cc
+++ b/gcc/simplify-rtx.cc
@@ -8438,7 +8438,7 @@ test_vector_subregs_fore_back (machine_mode inner_mode)
rtx x = builder.build ();
test_vector_subregs_modes (x);
- if (!nunits.is_constant ())
+ if (!nunits.is_constant () && known_ne (nunits, poly_uint16 (1, 1)))
test_vector_subregs_modes (x, nunits - min_nunits, count);
}
--
2.36.1
