In
https://gcc.gnu.org/git/?p=gcc.git;a=commit;h=d1eacedc6d9ba9f5522f2c8d49ccfdf7939ad72d
I optimize COND_LEN_xxx pattern with dummy len and dummy mask with too simply
solution which
causes redundant vsetvli in the following case:
vsetvli a5,a2,e8,m1,ta,ma
vle32.v v8,0(a0)
vsetivli zero,16,e32,m4,tu,mu ----> We should apply VLMAX
instead of a CONST_INT AVL
slli a4,a5,2
vand.vv v0,v8,v16
vand.vv v4,v8,v12
vmseq.vi v0,v0,0
sub a2,a2,a5
vneg.v v4,v8,v0.t
vsetvli zero,a5,e32,m4,ta,ma
The root cause above is the following codes:
is_vlmax_len_p (...)
return poly_int_rtx_p (len, &value)
&& known_eq (value, GET_MODE_NUNITS (mode))
&& !satisfies_constraint_K (len); ---> incorrect check.
Actually, we should not elide the VLMAX situation that has AVL in range of
[0,31].
After removing the the check above, we will have this following issue:
vsetivli zero,4,e32,m1,ta,ma
vlseg4e32.v v4,(a5)
vlseg4e32.v v12,(a3)
vsetvli a5,zero,e32,m1,tu,ma ---> This is redundant since
VLMAX AVL = 4 when it is fixed-vlmax
vfadd.vf v3,v13,fa0
vfadd.vf v1,v12,fa1
vfmul.vv v17,v3,v5
vfmul.vv v16,v1,v5
Since all the following operations (vfadd.vf ... etc) are COND_LEN_xxx with
dummy len and dummy mask,
we add the simplification operations dummy len and dummy mask into VLMAX TA and
MA policy.
So, after this patch. Both cases are optimal codegen now:
case 1:
vsetvli a5,a2,e32,m1,ta,mu
vle32.v v2,0(a0)
slli a4,a5,2
vand.vv v1,v2,v3
vand.vv v0,v2,v4
sub a2,a2,a5
vmseq.vi v0,v0,0
vneg.v v1,v2,v0.t
vse32.v v1,0(a1)
case 2:
vsetivli zero,4,e32,m1,tu,ma
addi a4,a5,400
vlseg4e32.v v12,(a3)
vfadd.vf v3,v13,fa0
vfadd.vf v1,v12,fa1
vlseg4e32.v v4,(a4)
vfadd.vf v2,v14,fa1
vfmul.vv v17,v3,v5
vfmul.vv v16,v1,v5
This patch is just additional fix of previous approved patch.
Tested on both RV32 and RV64 newlib no regression. Committed.
gcc/ChangeLog:
* config/riscv/riscv-v.cc (is_vlmax_len_p): Remove
satisfies_constraint_K.
(expand_cond_len_op): Add simplification of dummy len and dummy mask.
gcc/testsuite/ChangeLog:
* gcc.target/riscv/rvv/base/vf_avl-3.c: New test.
---
gcc/config/riscv/riscv-v.cc | 11 ++++++++---
gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-3.c | 11 +++++++++++
2 files changed, 19 insertions(+), 3 deletions(-)
create mode 100644 gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-3.c
diff --git a/gcc/config/riscv/riscv-v.cc b/gcc/config/riscv/riscv-v.cc
index b4c7e0f0126..3c83be35715 100644
--- a/gcc/config/riscv/riscv-v.cc
+++ b/gcc/config/riscv/riscv-v.cc
@@ -74,8 +74,7 @@ is_vlmax_len_p (machine_mode mode, rtx len)
{
poly_int64 value;
return poly_int_rtx_p (len, &value)
- && known_eq (value, GET_MODE_NUNITS (mode))
- && !satisfies_constraint_K (len);
+ && known_eq (value, GET_MODE_NUNITS (mode));
}
/* Helper functions for insn_flags && insn_types */
@@ -3855,7 +3854,13 @@ expand_cond_len_op (unsigned icode, insn_flags op_type,
rtx *ops, rtx len)
bool is_vlmax_len = is_vlmax_len_p (mode, len);
unsigned insn_flags = HAS_DEST_P | HAS_MASK_P | HAS_MERGE_P | op_type;
- if (is_dummy_mask)
+ /* FIXME: We don't support simplification of COND_LEN_NEG (..., dummy len,
+ dummy mask) into NEG_EXPR in GIMPLE FOLD yet. So, we do such
+ simplification in RISC-V backend and may do that in middle-end in the
+ future. */
+ if (is_dummy_mask && is_vlmax_len)
+ insn_flags |= TDEFAULT_POLICY_P | MDEFAULT_POLICY_P;
+ else if (is_dummy_mask)
insn_flags |= TU_POLICY_P | MDEFAULT_POLICY_P;
else if (is_vlmax_len)
insn_flags |= TDEFAULT_POLICY_P | MU_POLICY_P;
diff --git a/gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-3.c
b/gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-3.c
new file mode 100644
index 00000000000..116b5b538cc
--- /dev/null
+++ b/gcc/testsuite/gcc.target/riscv/rvv/base/vf_avl-3.c
@@ -0,0 +1,11 @@
+/* { dg-do compile } */
+/* { dg-options "-O3 -march=rv64gcv -mabi=lp64d --param
riscv-autovec-preference=fixed-vlmax" } */
+
+void foo (int *src, int *dst, int size) {
+ int i;
+ for (i = 0; i < size; i++)
+ *dst++ = *src & 0x80 ? (*src++ & 0x7f) : -*src++;
+}
+
+/* { dg-final { scan-assembler-times
{vsetvli\s+[a-x0-9]+,\s*[a-x0-9]+,\s*e32,\s*m1,\s*t[au],\s*mu} 1 } } */
+/* { dg-final { scan-assembler-times {vsetvli} 1 } } */
--
2.36.3
