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Merged
joshlf merged 1 commit into from
Apr 8, 2026
Merged

Optimize bounds checking by validating metadata against maximum #3123

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32 changes: 10 additions & 22 deletions benches/new_box_zeroed_with_elems_dynamic_padding.x86-64
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joshlf marked this conversation as resolved.
Original file line number Diff line number Diff line change
Expand Up @@ -3,32 +3,20 @@ bench_new_box_zeroed_with_elems_dynamic_padding:
push rbx
push rax
mov rbx, rdi
mov ecx, 3
mov rax, rdi
mul rcx
jo .LBB5_6
mov r14, rax
cmp rax, -10
ja .LBB5_6
lea rax, [r14 + 9]
not r14d
and r14d, 3
add r14, rax
setb al
movabs rcx, 9223372036854775803
cmp r14, rcx
seta cl
or cl, al
je .LBB5_4
.LBB5_6:
xor eax, eax
jmp .LBB5_5
.LBB5_4:
movabs rax, 3074457345618258598
cmp rdi, rax
ja .LBB5_1
lea r14, [rbx + 2*rbx]
or r14, 3
add r14, 9
call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
mov esi, 4
mov rdi, r14
call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
.LBB5_5:
jmp .LBB5_3
.LBB5_1:
xor eax, eax
.LBB5_3:
mov rdx, rbx
add rsp, 8
pop rbx
Expand Down
86 changes: 32 additions & 54 deletions benches/new_box_zeroed_with_elems_dynamic_padding.x86-64.mca
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Original file line number Diff line number Diff line change
@@ -1,12 +1,12 @@
Iterations: 100
Instructions: 3200
Total Cycles: 2989
Total uOps: 4300
Instructions: 2100
Total Cycles: 2990
Total uOps: 3000

Dispatch Width: 4
uOps Per Cycle: 1.44
IPC: 1.07
Block RThroughput: 10.8
uOps Per Cycle: 1.00
IPC: 0.70
Block RThroughput: 7.5


Instruction Info:
Expand All @@ -22,29 +22,18 @@ Instruction Info:
2 5 1.00 * push rbx
2 5 1.00 * push rax
1 1 0.33 mov rbx, rdi
1 1 0.33 mov ecx, 3
1 1 0.33 mov rax, rdi
2 4 1.00 mul rcx
1 1 1.00 jo .LBB5_6
1 1 0.33 mov r14, rax
1 1 0.33 cmp rax, -10
1 1 1.00 ja .LBB5_6
1 1 0.50 lea rax, [r14 + 9]
1 1 0.33 not r14d
1 1 0.33 and r14d, 3
1 1 0.33 add r14, rax
1 1 0.50 setb al
1 1 0.33 movabs rcx, 9223372036854775803
1 1 0.33 cmp r14, rcx
2 2 1.00 seta cl
1 1 0.33 or cl, al
1 1 1.00 je .LBB5_4
1 0 0.25 xor eax, eax
1 1 1.00 jmp .LBB5_5
1 1 0.33 movabs rax, 3074457345618258598
1 1 0.33 cmp rdi, rax
1 1 1.00 ja .LBB5_1
1 1 0.50 lea r14, [rbx + 2*rbx]
1 1 0.33 or r14, 3
1 1 0.33 add r14, 9
4 7 1.00 * call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
1 1 0.33 mov esi, 4
1 1 0.33 mov rdi, r14
4 7 1.00 * call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
1 1 1.00 jmp .LBB5_3
1 0 0.25 xor eax, eax
1 1 0.33 mov rdx, rbx
1 1 0.33 add rsp, 8
1 6 0.50 * pop rbx
Expand All @@ -65,39 +54,28 @@ Resources:

Resource pressure per iteration:
[0] [1] [2] [3] [4] [5] [6.0] [6.1]
- - 8.99 8.98 5.00 10.03 4.49 4.51
- - 4.49 4.50 5.00 6.01 4.50 4.50

Resource pressure by instruction:
[0] [1] [2] [3] [4] [5] [6.0] [6.1] Instructions:
- - - - 1.00 - 0.49 0.51 push r14
- - - - 1.00 - 0.51 0.49 push rbx
- - - - 1.00 - 0.49 0.51 push rax
- - 0.95 0.04 - 0.01 - - mov rbx, rdi
- - - 0.97 - 0.03 - - mov ecx, 3
- - 0.02 0.02 - 0.96 - - mov rax, rdi
- - 1.00 1.00 - - - - mul rcx
- - - - - 1.00 - - jo .LBB5_6
- - 0.02 0.97 - 0.01 - - mov r14, rax
- - 0.97 0.03 - - - - cmp rax, -10
- - - - - 1.00 - - ja .LBB5_6
- - 0.99 0.01 - - - - lea rax, [r14 + 9]
- - 0.01 0.99 - - - - not r14d
- - 0.97 0.03 - - - - and r14d, 3
- - 0.01 0.98 - 0.01 - - add r14, rax
- - 1.00 - - - - - setb al
- - 0.02 - - 0.98 - - movabs rcx, 9223372036854775803
- - - 0.97 - 0.03 - - cmp r14, rcx
- - 2.00 - - - - - seta cl
- - 0.03 0.03 - 0.94 - - or cl, al
- - - - - 1.00 - - je .LBB5_4
- - - - 1.00 - 0.50 0.50 push r14
- - - - 1.00 - 0.50 0.50 push rbx
- - - - 1.00 - 0.50 0.50 push rax
- - 0.49 0.50 - 0.01 - - mov rbx, rdi
- - 0.50 0.50 - - - - movabs rax, 3074457345618258598
- - 0.50 0.50 - - - - cmp rdi, rax
- - - - - 1.00 - - ja .LBB5_1
- - 0.50 0.50 - - - - lea r14, [rbx + 2*rbx]
- - 0.50 0.50 - - - - or r14, 3
- - 0.50 - - 0.50 - - add r14, 9
- - - - 1.00 1.00 1.00 1.00 call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
- - - 0.50 - 0.50 - - mov esi, 4
- - 0.50 0.50 - - - - mov rdi, r14
- - - - 1.00 1.00 1.00 1.00 call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
- - - - - 1.00 - - jmp .LBB5_3
- - - - - - - - xor eax, eax
- - - - - 1.00 - - jmp .LBB5_5
- - - - 1.00 1.00 1.02 0.98 call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
- - 0.03 0.97 - - - - mov esi, 4
- - 0.96 0.01 - 0.03 - - mov rdi, r14
- - - - 1.00 1.00 0.98 1.02 call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
- - - 0.97 - 0.03 - - mov rdx, rbx
- - 0.01 0.99 - - - - add rsp, 8
- - 0.51 0.49 - - - - mov rdx, rbx
- - 0.49 0.51 - - - - add rsp, 8
- - - - - - 0.50 0.50 pop rbx
- - - - - - 0.50 0.50 pop r14
- - - - - 1.00 - - ret
10 changes: 5 additions & 5 deletions benches/new_box_zeroed_with_elems_dynamic_size.x86-64
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Original file line number Diff line number Diff line change
Expand Up @@ -3,17 +3,17 @@ bench_new_box_zeroed_with_elems_dynamic_size:
push rbx
push rax
mov rbx, rdi
movabs rax, 4611686018427387900
movabs rax, 4611686018427387901
cmp rdi, rax
jbe .LBB5_2
xor eax, eax
jmp .LBB5_3
.LBB5_2:
ja .LBB5_1
lea r14, [2*rbx + 4]
call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
mov esi, 2
mov rdi, r14
call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
jmp .LBB5_3
.LBB5_1:
xor eax, eax
.LBB5_3:
mov rdx, rbx
add rsp, 8
Expand Down
32 changes: 16 additions & 16 deletions benches/new_box_zeroed_with_elems_dynamic_size.x86-64.mca
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Original file line number Diff line number Diff line change
Expand Up @@ -22,16 +22,16 @@ Instruction Info:
2 5 1.00 * push rbx
2 5 1.00 * push rax
1 1 0.33 mov rbx, rdi
1 1 0.33 movabs rax, 4611686018427387900
1 1 0.33 movabs rax, 4611686018427387901
1 1 0.33 cmp rdi, rax
1 1 1.00 jbe .LBB5_2
1 0 0.25 xor eax, eax
1 1 1.00 jmp .LBB5_3
1 1 1.00 ja .LBB5_1
1 1 0.50 lea r14, [2*rbx + 4]
4 7 1.00 * call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
1 1 0.33 mov esi, 2
1 1 0.33 mov rdi, r14
4 7 1.00 * call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
1 1 1.00 jmp .LBB5_3
1 0 0.25 xor eax, eax
1 1 0.33 mov rdx, rbx
1 1 0.33 add rsp, 8
1 6 0.50 * pop rbx
Expand All @@ -52,26 +52,26 @@ Resources:

Resource pressure per iteration:
[0] [1] [2] [3] [4] [5] [6.0] [6.1]
- - 3.97 3.97 5.00 5.06 4.50 4.50
- - 3.97 3.98 5.00 5.05 4.50 4.50

Resource pressure by instruction:
[0] [1] [2] [3] [4] [5] [6.0] [6.1] Instructions:
- - - - 1.00 - 0.50 0.50 push r14
- - - - 1.00 - 0.50 0.50 push rbx
- - - - 1.00 - 0.50 0.50 push rax
- - 0.94 0.05 - 0.01 - - mov rbx, rdi
- - 0.05 0.95 - - - - movabs rax, 4611686018427387900
- - 0.95 - - 0.05 - - cmp rdi, rax
- - - - - 1.00 - - jbe .LBB5_2
- - - - - - - - xor eax, eax
- - - - - 1.00 - - jmp .LBB5_3
- - - 1.00 - - - - lea r14, [2*rbx + 4]
- - 0.05 0.94 - 0.01 - - mov rbx, rdi
- - 0.94 0.06 - - - - movabs rax, 4611686018427387901
- - 0.06 0.94 - - - - cmp rdi, rax
- - - - - 1.00 - - ja .LBB5_1
- - 0.94 0.06 - - - - lea r14, [2*rbx + 4]
- - - - 1.00 1.00 1.00 1.00 call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
- - 0.06 0.94 - - - - mov esi, 2
- - 0.94 0.06 - - - - mov rdi, r14
- - 0.98 0.02 - - - - mov esi, 2
- - 0.02 0.94 - 0.04 - - mov rdi, r14
- - - - 1.00 1.00 1.00 1.00 call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
- - 0.05 0.95 - - - - mov rdx, rbx
- - 0.98 0.02 - - - - add rsp, 8
- - - - - 1.00 - - jmp .LBB5_3
- - - - - - - - xor eax, eax
- - 0.94 0.06 - - - - mov rdx, rbx
- - 0.04 0.96 - - - - add rsp, 8
- - - - - - 0.50 0.50 pop rbx
- - - - - - 0.50 0.50 pop r14
- - - - - 1.00 - - ret
62 changes: 29 additions & 33 deletions benches/new_vec_zeroed.x86-64
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Original file line number Diff line number Diff line change
@@ -1,44 +1,40 @@
bench_new_vec_zeroed:
mov rax, rdi
movabs rcx, 1537228672809129301
cmp rsi, rcx
ja .LBB5_5
test rsi, rsi
je .LBB5_2
push r15
push r14
push r12
push rbx
push rax
mov rbx, rdi
movabs r12, 9223372036854775805
mov ecx, 6
mov rax, rsi
mul rcx
jo .LBB5_6
cmp rax, r12
jbe .LBB5_2
.LBB5_6:
add r12, 3
mov qword ptr [rbx], r12
jmp .LBB5_7
.LBB5_2:
mov r14, rsi
test rax, rax
je .LBB5_3
mov r15, rax
lea rcx, [rsi + rsi]
lea rbx, [rcx + 2*rcx]
mov r14, rax
mov r15, rsi
call qword ptr [rip + __rustc::__rust_no_alloc_shim_is_unstable_v2@GOTPCREL]
mov esi, 2
mov rdi, r15
mov rdi, rbx
call qword ptr [rip + __rustc::__rust_alloc_zeroed@GOTPCREL]
test rax, rax
jne .LBB5_5
jmp .LBB5_6
.LBB5_3:
mov eax, 2
.LBB5_5:
mov qword ptr [rbx], r14
mov qword ptr [rbx + 8], rax
mov qword ptr [rbx + 16], r14
.LBB5_7:
mov rax, rbx
add rsp, 8
mov rsi, r15
mov rcx, rax
mov rax, r14
test rcx, rcx
pop rbx
pop r12
pop r14
pop r15
je .LBB5_5
mov qword ptr [rax], rsi
mov qword ptr [rax + 8], rcx
mov qword ptr [rax + 16], rsi
ret
.LBB5_5:
movabs rcx, -9223372036854775808
mov qword ptr [rax], rcx
ret
.LBB5_2:
mov ecx, 2
mov qword ptr [rax], rsi
mov qword ptr [rax + 8], rcx
mov qword ptr [rax + 16], rsi
ret
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