哇这个 GCC 9.3 的杂鱼展开好可爱呀
Redshift_Shine · · 科技·工程
来源：cyffff 的神秘挂分。
那我可就来兴趣了啊。直接拿来他的代码丢进 Compiler Explorer 里面编译，使用 GCC 9.3，开 O2 优化，启动！
若干秒之后
:::error[这 tm 啥啊？？？]
lea eax, [rbx+1]
sar eax
lea r14d, [rax+1]
mov ebp, eax
lea eax, [r14+rbx]
sar eax
lea ecx, [rax+1]
mov r12d, eax
lea eax, [rcx+rbx]
mov DWORD PTR [rsp+56], ecx
sar eax
lea edx, [rax+1]
mov esi, eax
mov DWORD PTR [rsp+72], eax
lea eax, [rdx+rbx]
mov DWORD PTR [rsp+120], edx
sar eax
lea r10d, [rax+1]
mov edi, eax
mov DWORD PTR [rsp+104], eax
lea eax, [r10+rbx]
mov DWORD PTR [rsp+364], r10d
sar eax
mov r11d, eax
mov DWORD PTR [rsp+180], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+300], eax
add eax, ebx
sar eax
mov DWORD PTR [rsp+776], eax
add eax, 1
mov DWORD PTR [rsp+780], eax
mov eax, r11d
add eax, r10d
sar eax
mov r8d, eax
mov DWORD PTR [rsp+268], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+856], eax
add eax, r11d
sar eax
mov DWORD PTR [rsp+768], eax
add eax, 1
mov DWORD PTR [rsp+772], eax
mov eax, r8d
add eax, r10d
sar eax
mov DWORD PTR [rsp+760], eax
add eax, 1
mov DWORD PTR [rsp+764], eax
mov eax, edi
add eax, edx
sar eax
mov r11d, eax
mov DWORD PTR [rsp+176], eax
lea eax, [rax+1]
add edi, eax
mov DWORD PTR [rsp+296], eax
mov eax, edi
sar eax
mov DWORD PTR [rsp+752], eax
add eax, 1
mov DWORD PTR [rsp+756], eax
mov eax, edx
add eax, r11d
sar eax
mov edi, eax
mov DWORD PTR [rsp+264], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+844], eax
add eax, r11d
sar eax
mov DWORD PTR [rsp+744], eax
add eax, 1
mov DWORD PTR [rsp+748], eax
mov eax, edi
add eax, edx
mov edx, esi
sar eax
mov DWORD PTR [rsp+736], eax
add eax, 1
mov DWORD PTR [rsp+740], eax
mov eax, ecx
add eax, esi
sar eax
lea edi, [rax+1]
mov esi, eax
mov DWORD PTR [rsp+88], eax
mov eax, edi
mov DWORD PTR [rsp+292], edi
add eax, edx
sar eax
mov r11d, eax
mov DWORD PTR [rsp+172], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+356], eax
add eax, edx
sar eax
mov DWORD PTR [rsp+728], eax
add eax, 1
mov DWORD PTR [rsp+732], eax
mov eax, edi
add eax, r11d
sar eax
mov DWORD PTR [rsp+260], eax
mov edx, eax
lea eax, [rax+1]
add r11d, eax
mov DWORD PTR [rsp+848], eax
mov eax, r11d
sar eax
mov DWORD PTR [rsp+720], eax
add eax, 1
mov DWORD PTR [rsp+724], eax
mov eax, edi
add eax, edx
sar eax
mov DWORD PTR [rsp+712], eax
add eax, 1
mov DWORD PTR [rsp+716], eax
mov eax, esi
add eax, ecx
sar eax
lea r8d, [rax+1]
mov edi, eax
mov DWORD PTR [rsp+168], eax
mov eax, r8d
mov DWORD PTR [rsp+360], r8d
add eax, esi
sar eax
mov edx, eax
mov DWORD PTR [rsp+256], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+852], eax
add eax, esi
sar eax
mov DWORD PTR [rsp+704], eax
add eax, 1
mov DWORD PTR [rsp+708], eax
mov eax, edx
add eax, r8d
sar eax
mov DWORD PTR [rsp+696], eax
add eax, 1
mov DWORD PTR [rsp+700], eax
mov eax, edi
add eax, ecx
sar eax
mov esi, eax
mov DWORD PTR [rsp+252], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+792], eax
add eax, edi
sar eax
mov DWORD PTR [rsp+688], eax
add eax, 1
mov DWORD PTR [rsp+692], eax
mov eax, esi
add eax, ecx
sar eax
mov DWORD PTR [rsp+680], eax
add eax, 1
mov DWORD PTR [rsp+684], eax
lea eax, [r12+r14]
sar eax
lea esi, [rax+1]
mov edi, eax
mov DWORD PTR [rsp+68], eax
lea eax, [r12+rsi]
mov DWORD PTR [rsp+112], esi
sar eax
lea r10d, [rax+1]
mov ecx, eax
mov DWORD PTR [rsp+100], eax
lea eax, [r12+r10]
mov DWORD PTR [rsp+352], r10d
sar eax
mov edx, eax
mov DWORD PTR [rsp+164], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+288], eax
add eax, r12d
sar eax
mov DWORD PTR [rsp+672], eax
add eax, 1
mov DWORD PTR [rsp+676], eax
mov eax, edx
add eax, r10d
sar eax
mov r11d, eax
mov DWORD PTR [rsp+248], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+840], eax
add eax, edx
sar eax
mov DWORD PTR [rsp+664], eax
add eax, 1
mov DWORD PTR [rsp+668], eax
mov eax, r11d
add eax, r10d
mov r10d, r14d
sar eax
mov DWORD PTR [rsp+656], eax
add eax, 1
mov DWORD PTR [rsp+660], eax
mov eax, ecx
add eax, esi
sar eax
mov edx, eax
mov DWORD PTR [rsp+160], eax
lea eax, [rax+1]
add ecx, eax
mov DWORD PTR [rsp+284], eax
mov eax, ecx
sar eax
mov DWORD PTR [rsp+648], eax
add eax, 1
mov DWORD PTR [rsp+652], eax
mov eax, esi
add eax, edx
sar eax
mov ecx, eax
mov DWORD PTR [rsp+244], eax
lea eax, [rax+1]
add edx, eax
mov DWORD PTR [rsp+836], eax
add esi, ecx
mov ecx, edi
mov eax, edx
sar eax
mov DWORD PTR [rsp+640], eax
add eax, 1
mov DWORD PTR [rsp+644], eax
mov eax, esi
sar eax
mov DWORD PTR [rsp+632], eax
add eax, 1
mov DWORD PTR [rsp+636], eax
lea eax, [rdi+r14]
sar eax
lea edi, [rax+1]
mov esi, eax
mov DWORD PTR [rsp+84], eax
mov eax, edi
mov DWORD PTR [rsp+280], edi
add eax, ecx
sar eax
mov edx, eax
mov DWORD PTR [rsp+156], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+340], eax
add eax, ecx
sar eax
mov DWORD PTR [rsp+624], eax
add eax, 1
mov DWORD PTR [rsp+628], eax
mov eax, edi
add eax, edx
sar eax
sar r10d
mov ecx, eax
mov DWORD PTR [rsp+240], eax
lea eax, [rax+1]
add edx, eax
mov DWORD PTR [rsp+828], eax
mov eax, edx
sar eax
mov DWORD PTR [rsp+616], eax
add eax, 1
mov DWORD PTR [rsp+620], eax
mov eax, edi
add eax, ecx
sar eax
mov DWORD PTR [rsp+608], eax
add eax, 1
mov DWORD PTR [rsp+612], eax
lea eax, [rsi+r14]
sar eax
lea edx, [rax+1]
mov ecx, eax
mov DWORD PTR [rsp+152], eax
mov eax, edx
mov DWORD PTR [rsp+348], edx
add eax, esi
sar eax
mov edi, eax
mov DWORD PTR [rsp+236], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+832], eax
add eax, esi
sar eax
mov DWORD PTR [rsp+600], eax
add eax, 1
mov DWORD PTR [rsp+604], eax
mov eax, edi
add eax, edx
sar eax
mov DWORD PTR [rsp+592], eax
add eax, 1
mov DWORD PTR [rsp+596], eax
lea eax, [rcx+r14]
sar eax
mov edi, eax
mov DWORD PTR [rsp+232], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+788], eax
add eax, ecx
lea ecx, [r10+1]
sar eax
mov DWORD PTR [rsp+584], eax
add eax, 1
mov DWORD PTR [rsp+588], eax
lea eax, [rdi+r14]
sar eax
mov DWORD PTR [rsp+8], r10d
mov DWORD PTR [rsp+576], eax
add eax, 1
mov DWORD PTR [rsp+580], eax
lea eax, [rcx+rbp]
sar eax
mov DWORD PTR [rsp+52], ecx
lea r8d, [rax+1]
mov edi, eax
mov DWORD PTR [rsp+64], eax
lea eax, [r8+rbp]
mov DWORD PTR [rsp+116], r8d
sar eax
lea edx, [rax+1]
mov esi, eax
mov DWORD PTR [rsp+96], eax
lea eax, [rdx+rbp]
mov DWORD PTR [rsp+276], edx
sar eax
mov r11d, eax
mov DWORD PTR [rsp+148], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+344], eax
add eax, ebp
sar eax
mov DWORD PTR [rsp+568], eax
add eax, 1
mov DWORD PTR [rsp+572], eax
mov eax, edx
add eax, r11d
sar eax
mov r13d, eax
mov DWORD PTR [rsp+228], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+800], eax
add eax, r11d
sar eax
mov DWORD PTR [rsp+560], eax
add eax, 1
mov DWORD PTR [rsp+564], eax
mov eax, edx
add eax, r13d
mov r13, r9
sar eax
mov DWORD PTR [rsp+552], eax
add eax, 1
mov DWORD PTR [rsp+556], eax
mov eax, esi
add eax, r8d
sar eax
mov edx, eax
mov DWORD PTR [rsp+144], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+336], eax
add eax, esi
sar eax
mov DWORD PTR [rsp+544], eax
add eax, 1
mov DWORD PTR [rsp+548], eax
mov eax, edx
add eax, r8d
sar eax
mov esi, eax
mov DWORD PTR [rsp+224], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+796], eax
add eax, edx
sar eax
mov DWORD PTR [rsp+536], eax
add eax, 1
mov DWORD PTR [rsp+540], eax
mov eax, esi
add eax, r8d
sar eax
mov DWORD PTR [rsp+528], eax
add eax, 1
mov DWORD PTR [rsp+532], eax
mov eax, edi
add eax, ecx
sar eax
lea r11d, [rax+1]
mov esi, eax
mov DWORD PTR [rsp+80], eax
mov eax, edi
add eax, r11d
mov DWORD PTR [rsp+324], r11d
sar eax
mov edx, eax
mov DWORD PTR [rsp+140], eax
lea eax, [rax+1]
add edi, eax
mov DWORD PTR [rsp+332], eax
mov eax, edi
sar eax
mov DWORD PTR [rsp+520], eax
add eax, 1
mov DWORD PTR [rsp+524], eax
mov eax, edx
add eax, r11d
sar eax
mov edi, eax
mov DWORD PTR [rsp+220], eax
lea eax, [rax+1]
add edx, eax
mov DWORD PTR [rsp+824], eax
mov eax, edx
sar eax
mov DWORD PTR [rsp+512], eax
add eax, 1
mov DWORD PTR [rsp+516], eax
mov eax, edi
add eax, r11d
sar eax
mov DWORD PTR [rsp+504], eax
add eax, 1
mov DWORD PTR [rsp+508], eax
mov eax, esi
add eax, ecx
sar eax
lea r8d, [rax+1]
mov edi, eax
mov DWORD PTR [rsp+136], eax
mov eax, esi
add eax, r8d
mov DWORD PTR [rsp+328], r8d
sar eax
mov edx, eax
mov DWORD PTR [rsp+216], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+816], eax
add eax, esi
sar eax
mov DWORD PTR [rsp+496], eax
add eax, 1
mov DWORD PTR [rsp+500], eax
mov eax, edx
add eax, r8d
sar eax
mov DWORD PTR [rsp+488], eax
add eax, 1
mov DWORD PTR [rsp+492], eax
mov eax, edi
add eax, ecx
sar eax
mov esi, eax
mov DWORD PTR [rsp+212], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+812], eax
add eax, edi
sar eax
mov DWORD PTR [rsp+480], eax
add eax, 1
mov DWORD PTR [rsp+484], eax
mov eax, esi
add eax, ecx
sar ecx
sar eax
mov edi, ecx
mov DWORD PTR [rsp+60], ecx
lea ecx, [rcx+1]
mov DWORD PTR [rsp+472], eax
add eax, 1
mov DWORD PTR [rsp+476], eax
mov eax, ecx
add eax, r10d
mov DWORD PTR [rsp+108], ecx
sar eax
lea edx, [rax+1]
mov esi, eax
mov DWORD PTR [rsp+92], eax
mov eax, edx
mov DWORD PTR [rsp+272], edx
add eax, r10d
sar eax
mov r11d, eax
mov DWORD PTR [rsp+132], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+320], eax
add eax, r10d
sar eax
mov DWORD PTR [rsp+464], eax
add eax, 1
mov DWORD PTR [rsp+468], eax
mov eax, edx
add eax, r11d
sar eax
mov DWORD PTR [rsp+208], eax
mov r8d, eax
lea eax, [rax+1]
mov DWORD PTR [rsp+820], eax
add eax, r11d
sar eax
mov DWORD PTR [rsp+456], eax
add eax, 1
mov DWORD PTR [rsp+460], eax
mov eax, edx
add eax, r8d
sar eax
mov DWORD PTR [rsp+448], eax
add eax, 1
mov DWORD PTR [rsp+452], eax
mov eax, esi
add eax, ecx
sar eax
lea r10d, [rax+1]
mov edx, eax
mov DWORD PTR [rsp+128], eax
add esi, r10d
mov DWORD PTR [rsp+316], r10d
mov eax, esi
sar eax
lea esi, [rax+1]
mov DWORD PTR [rsp+204], eax
add eax, r10d
sar eax
mov DWORD PTR [rsp+436], esi
mov DWORD PTR [rsp+440], eax
add eax, 1
mov DWORD PTR [rsp+444], eax
mov eax, ecx
add eax, edx
sar eax
mov esi, eax
mov DWORD PTR [rsp+200], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+808], eax
add eax, edx
sar eax
mov DWORD PTR [rsp+428], eax
add eax, 1
mov DWORD PTR [rsp+432], eax
mov eax, esi
add eax, ecx
sar ecx
sar eax
lea esi, [rcx+1]
mov DWORD PTR [rsp+76], ecx
mov DWORD PTR [rsp+420], eax
add eax, 1
mov DWORD PTR [rsp+424], eax
mov eax, edi
add eax, esi
mov DWORD PTR [rsp+312], esi
sar eax
mov edx, eax
mov DWORD PTR [rsp+124], eax
lea eax, [rax+1]
add edi, eax
mov DWORD PTR [rsp+308], eax
mov eax, edi
mov edi, esi
sar eax
mov DWORD PTR [rsp+412], eax
add eax, 1
mov DWORD PTR [rsp+416], eax
mov eax, edx
add eax, esi
sar eax
mov esi, eax
mov DWORD PTR [rsp+196], eax
lea eax, [rax+1]
mov DWORD PTR [rsp+784], eax
add eax, edx
sar eax
mov DWORD PTR [rsp+404], eax
add eax, 1
mov DWORD PTR [rsp+408], eax
mov eax, esi
add eax, edi
sar eax
mov DWORD PTR [rsp+396], eax
add eax, 1
sar edi
mov DWORD PTR [rsp+400], eax
mov eax, ecx
mov DWORD PTR [rsp+184], edi
add edi, 1
add eax, edi
mov DWORD PTR [rsp+304], edi
sar eax
mov DWORD PTR [rsp+192], eax
mov esi, eax
lea eax, [rax+1]
add ecx, eax
mov DWORD PTR [rsp+804], eax
mov eax, ecx
sar eax
mov DWORD PTR [rsp+388], eax
add eax, 1
mov DWORD PTR [rsp+392], eax
mov eax, esi
add eax, edi
sar edi
mov DWORD PTR [rsp+16], r12d
sar eax
mov DWORD PTR [rsp+188], edi
mov DWORD PTR [rsp+380], eax
add eax, 1
mov DWORD PTR [rsp+384], eax
lea eax, [rdi+1]
mov DWORD PTR [rsp+368], eax
sar eax
mov DWORD PTR [rsp+372], eax
add eax, 1
mov DWORD PTR [rsp+376], eax:::
温馨提醒：上面的所有东西都是从同一个函数里炸出来的：
inline int query(int rt,int l,int r,int p){
if(!rt) return 0;
if(l==r) return a[rt].tag;
int mid=l+r>>1;
if(p<=mid) return query(ls,l,mid,p)+a[rt].tag;
else return query(rs,mid+1,r,p)+a[rt].tag;
}不行赶紧关掉 O2，它在干啥啊？？？
若干秒之后
:::info[哎呀你看这不就正常多了吗]
Segment_Tree::query(int, int, int, int):
push rbp
mov rbp, rsp
sub rsp, 48
mov QWORD PTR [rbp-24], rdi
mov DWORD PTR [rbp-28], esi
mov DWORD PTR [rbp-32], edx
mov DWORD PTR [rbp-36], ecx
mov DWORD PTR [rbp-40], r8d
cmp DWORD PTR [rbp-28], 0
jne .L42
mov eax, 0
jmp .L43
.L42:
mov eax, DWORD PTR [rbp-32]
cmp eax, DWORD PTR [rbp-36]
jne .L44
mov rcx, QWORD PTR [rbp-24]
mov eax, DWORD PTR [rbp-28]
movsx rdx, eax
mov rax, rdx
add rax, rax
add rax, rdx
sal rax, 2
add rax, rcx
add rax, 8
mov eax, DWORD PTR [rax]
jmp .L43
.L44:
mov edx, DWORD PTR [rbp-32]
mov eax, DWORD PTR [rbp-36]
add eax, edx
sar eax
mov DWORD PTR [rbp-4], eax
mov eax, DWORD PTR [rbp-40]
cmp eax, DWORD PTR [rbp-4]
jg .L45
mov rcx, QWORD PTR [rbp-24]
mov eax, DWORD PTR [rbp-28]
movsx rdx, eax
mov rax, rdx
add rax, rax
add rax, rdx
sal rax, 2
add rax, rcx
mov esi, DWORD PTR [rax]
mov edi, DWORD PTR [rbp-40]
mov ecx, DWORD PTR [rbp-4]
mov edx, DWORD PTR [rbp-32]
mov rax, QWORD PTR [rbp-24]
mov r8d, edi
mov rdi, rax
call Segment_Tree::query(int, int, int, int)
mov ecx, eax
mov rsi, QWORD PTR [rbp-24]
mov eax, DWORD PTR [rbp-28]
movsx rdx, eax
mov rax, rdx
add rax, rax
add rax, rdx
sal rax, 2
add rax, rsi
add rax, 8
mov eax, DWORD PTR [rax]
add eax, ecx
jmp .L43
.L45:
mov eax, DWORD PTR [rbp-4]
lea edi, [rax+1]
mov rcx, QWORD PTR [rbp-24]
mov eax, DWORD PTR [rbp-28]
movsx rdx, eax
mov rax, rdx
add rax, rax
add rax, rdx
sal rax, 2
add rax, rcx
add rax, 4
mov esi, DWORD PTR [rax]
mov ecx, DWORD PTR [rbp-40]
mov edx, DWORD PTR [rbp-36]
mov rax, QWORD PTR [rbp-24]
mov r8d, ecx
mov ecx, edx
mov edx, edi
mov rdi, rax
call Segment_Tree::query(int, int, int, int)
mov ecx, eax
mov rsi, QWORD PTR [rbp-24]
mov eax, DWORD PTR [rbp-28]
movsx rdx, eax
mov rax, rdx
add rax, rax
add rax, rdx
sal rax, 2
add rax, rsi
add rax, 8
mov eax, DWORD PTR [rax]
add eax, ecx
.L43:
leave
ret:::
那是不是旧的编译器太笨了啊？换个编译器试试（选中 GCC 15.2）。
若干秒之后
:::info[你看这不就是正常的吗？？？]
Segment_Tree::query(int, int, int, int):
xor eax, eax
test esi, esi
je .L366
cmp edx, ecx
je .L370
mov r10d, ecx
movsx rsi, esi
lea ecx, [rdx+rcx]
sub rsp, 24
lea rax, [rsi+rsi*2]
sar ecx
lea r9, [rdi+rax*4]
cmp ecx, r8d
jl .L350
movsx rax, DWORD PTR [r9]
test eax, eax
je .L354
cmp edx, ecx
je .L368
lea r10d, [rdx+rcx]
lea rax, [rax+rax*2]
mov QWORD PTR [rsp+8], r9
sar r10d
lea r11, [rdi+rax*4]
cmp r8d, r10d
jg .L353
mov esi, DWORD PTR [r11]
.L369:
mov ecx, r10d
mov QWORD PTR [rsp], r11
call Segment_Tree::query(int, int, int, int)
mov r11, QWORD PTR [rsp]
mov r9, QWORD PTR [rsp+8]
add eax, DWORD PTR [r11+8]
.L354:
add eax, DWORD PTR [r9+8]
add rsp, 24
ret
.L350:
movsx rax, DWORD PTR [r9+4]
test eax, eax
je .L354
lea edx, [rcx+1]
cmp edx, r10d
je .L368
lea ecx, [rdx+r10]
mov QWORD PTR [rsp+8], r9
lea rax, [rax+rax*2]
sar ecx
cmp r8d, ecx
jg .L356
lea r10, [rdi+rax*4]
mov esi, DWORD PTR [r10]
mov QWORD PTR [rsp], r10
call Segment_Tree::query(int, int, int, int)
mov r10, QWORD PTR [rsp]
mov r9, QWORD PTR [rsp+8]
add eax, DWORD PTR [r10+8]
jmp .L354
.L366:
ret
.L370:
movsx rsi, esi
lea rax, [rsi+rsi*2]
mov eax, DWORD PTR [rdi+8+rax*4]
ret
.L368:
lea rax, [rax+rax*2]
mov eax, DWORD PTR [rdi+8+rax*4]
jmp .L354
.L356:
lea r11, [rdi+rax*4]
lea edx, [rcx+1]
mov esi, DWORD PTR [r11+4]
jmp .L369
.L353:
mov esi, DWORD PTR [r11+4]
lea edx, [r10+1]
mov QWORD PTR [rsp], r11
call Segment_Tree::query(int, int, int, int)
mov r11, QWORD PTR [rsp]
mov r9, QWORD PTR [rsp+8]
add eax, DWORD PTR [r11+8]
jmp .L354:::
欸你说它展开是不是因为它看到了那个 inline 啊？把配置调回去删掉 inline 试试。
若干秒之后
你完全不听是吧？还在展开？
评价是某协会都 2025 年了有 GCC 15.2 了还在用 GCC 9.3 完全就是不知所云。不过对于普通选手的我们还有救吗？完全不知道，还是听天由命吧。