From: Pan Li <pan2...@intel.com>
This patch would like to combine the vec_duplicate + vadd.vv to the
vadd.vx. From example as below code. The related pattern will depend
on the cost of vec_duplicate from GR2VR, it will:
* The pattern matching will be active by default.
* The cost of GR2VR will be added to the total cost of pattern, aka:
vec_dup cost = gr2vr_cost
vadd.vv v, (vec_dup (x)) = gr2vr_cost + 1
Then the late-combine will take action if the cost of GR2VR is zero,
and reject the combination if the GR2VR cost is greater than zero.
Assume we have example code like below, GR2VR cost is 0.
#define DEF_VX_BINARY(T, OP) \
void \
test_vx_binary (T * restrict out, T * restrict in, T x, unsigned n) \
{ \
for (unsigned i = 0; i < n; i++) \
out[i] = in[i] OP x; \
}
DEF_VX_BINARY(int32_t, +)
Before this patch:
10 │ test_binary_vx_add:
11 │ beq a3,zero,.L8
12 │ vsetvli a5,zero,e32,m1,ta,ma // Deleted if GR2VR cost zero
13 │ vmv.v.x v2,a2 // Ditto.
14 │ slli a3,a3,32
15 │ srli a3,a3,32
16 │ .L3:
17 │ vsetvli a5,a3,e32,m1,ta,ma
18 │ vle32.v v1,0(a1)
19 │ slli a4,a5,2
20 │ sub a3,a3,a5
21 │ add a1,a1,a4
22 │ vadd.vv v1,v2,v1
23 │ vse32.v v1,0(a0)
24 │ add a0,a0,a4
25 │ bne a3,zero,.L3
After this patch:
10 │ test_binary_vx_add:
11 │ beq a3,zero,.L8
12 │ slli a3,a3,32
13 │ srli a3,a3,32
14 │ .L3:
15 │ vsetvli a5,a3,e32,m1,ta,ma
16 │ vle32.v v1,0(a1)
17 │ slli a4,a5,2
18 │ sub a3,a3,a5
19 │ add a1,a1,a4
20 │ vadd.vx v1,v1,a2
21 │ vse32.v v1,0(a0)
22 │ add a0,a0,a4
23 │ bne a3,zero,.L3
The below test suites are passed for this patch.
* The rv64gcv fully regression test.
gcc/ChangeLog:
* config/riscv/autovec-opt.md (*<optab>_vx_<mode>): Add new
combine to convert vec_duplicate + vadd.vv to vaddvx on GR2VR
cost.
* config/riscv/riscv.cc (riscv_rtx_costs): Take care of the cost
when vec_dup and vadd v, vec_dup(x).
* config/riscv/vector-iterators.md: Add new iterator for vx.
