Re: [PATCH bpf-next v5 1/2] bpf: Get better reg range with ldsx and 32bit compare

[patchwork-bot+netdevbpf@kernel.org]

Hello:

This series was applied to bpf/bpf-next.git (master)
by Alexei Starovoitov <ast@kernel.org>:

On Tue, 23 Jul 2024 09:29:33 -0700 you wrote:
> With latest llvm19, the selftest iters/iter_arr_with_actual_elem_count
> failed with -mcpu=v4.
> 
> The following are the details:
>   0: R1=ctx() R10=fp0
>   ; int iter_arr_with_actual_elem_count(const void *ctx) @ iters.c:1420
>   0: (b4) w7 = 0                        ; R7_w=0
>   ; int i, n = loop_data.n, sum = 0; @ iters.c:1422
>   1: (18) r1 = 0xffffc90000191478       ; R1_w=map_value(map=iters.bss,ks=4,vs=1280,off=1144)
>   3: (61) r6 = *(u32 *)(r1 +128)        ; R1_w=map_value(map=iters.bss,ks=4,vs=1280,off=1144) R6_w=scalar(smin=0,smax=umax=0xffffffff,var_off=(0x0; 0xffffffff))
>   ; if (n > ARRAY_SIZE(loop_data.data)) @ iters.c:1424
>   4: (26) if w6 > 0x20 goto pc+27       ; R6_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=32,var_off=(0x0; 0x3f))
>   5: (bf) r8 = r10                      ; R8_w=fp0 R10=fp0
>   6: (07) r8 += -8                      ; R8_w=fp-8
>   ; bpf_for(i, 0, n) { @ iters.c:1427
>   7: (bf) r1 = r8                       ; R1_w=fp-8 R8_w=fp-8
>   8: (b4) w2 = 0                        ; R2_w=0
>   9: (bc) w3 = w6                       ; R3_w=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=32,var_off=(0x0; 0x3f)) R6_w=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=32,var_off=(0x0; 0x3f))
>   10: (85) call bpf_iter_num_new#45179          ; R0=scalar() fp-8=iter_num(ref_id=2,state=active,depth=0) refs=2
>   11: (bf) r1 = r8                      ; R1=fp-8 R8=fp-8 refs=2
>   12: (85) call bpf_iter_num_next#45181 13: R0=rdonly_mem(id=3,ref_obj_id=2,sz=4) R6=scalar(id=1,smin=smin32=0,smax=umax=smax32=umax32=32,var_off=(0x0; 0x3f)) R7=0 R8=fp-8 R10=fp0 fp-8=iter_num(ref_id=2,state=active,depth=1) refs=2
>   ; bpf_for(i, 0, n) { @ iters.c:1427
>   13: (15) if r0 == 0x0 goto pc+2       ; R0=rdonly_mem(id=3,ref_obj_id=2,sz=4) refs=2
>   14: (81) r1 = *(s32 *)(r0 +0)         ; R0=rdonly_mem(id=3,ref_obj_id=2,sz=4) R1_w=scalar(smin=0xffffffff80000000,smax=0x7fffffff) refs=2
>   15: (ae) if w1 < w6 goto pc+4 20: R0=rdonly_mem(id=3,ref_obj_id=2,sz=4) R1=scalar(smin=0xffffffff80000000,smax=smax32=umax32=31,umax=0xffffffff0000001f,smin32=0,var_off=(0x0; 0xffffffff0000001f)) R6=scalar(id=1,smin=umin=smin32=umin32=1,smax=umax=smax32=umax32=32,var_off=(0x0; 0x3f)) R7=0 R8=fp-8 R10=fp0 fp-8=iter_num(ref_id=2,state=active,depth=1) refs=2
>   ; sum += loop_data.data[i]; @ iters.c:1429
>   20: (67) r1 <<= 2                     ; R1_w=scalar(smax=0x7ffffffc0000007c,umax=0xfffffffc0000007c,smin32=0,smax32=umax32=124,var_off=(0x0; 0xfffffffc0000007c)) refs=2
>   21: (18) r2 = 0xffffc90000191478      ; R2_w=map_value(map=iters.bss,ks=4,vs=1280,off=1144) refs=2
>   23: (0f) r2 += r1
>   math between map_value pointer and register with unbounded min value is not allowed
> 
> [...]

Here is the summary with links:
  - [bpf-next,v5,1/2] bpf: Get better reg range with ldsx and 32bit compare
    https://git.kernel.org/bpf/bpf-next/c/2e716457a823
  - [bpf-next,v5,2/2] selftests/bpf: Add reg_bounds tests for ldsx and subreg compare
    https://git.kernel.org/bpf/bpf-next/c/1d6189935f1d

You are awesome, thank you!
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