int u8charleni(int n) {
  if (n <= 0)
    return 0;
  if (n < 0x80)
    return 1;
  if (n < 0x800)
    return 2;
  if (n < 0x10000)
    return 3;
  if (n < 0x200000)
    return 4;
  if (n < 0x4000000)
    return 5;
  if (n < 0x80000000)
    return 6;
  return 0;
}


x86 assembly (clang, -O0):
<u8charleni>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0x8(%rbp)
cmpl   $0x0,-0x8(%rbp)
jg     111d <u8charleni+0x1d>
movl   $0x0,-0x4(%rbp)
jmp    11ba <u8charleni+0xba>
cmpl   $0x80,-0x8(%rbp)
jge    1136 <u8charleni+0x36>
movl   $0x1,-0x4(%rbp)
jmp    11ba <u8charleni+0xba>
cmpl   $0x800,-0x8(%rbp)
jge    114f <u8charleni+0x4f>
movl   $0x2,-0x4(%rbp)
jmp    11ba <u8charleni+0xba>
cmpl   $0x10000,-0x8(%rbp)
jge    1168 <u8charleni+0x68>
movl   $0x3,-0x4(%rbp)
jmp    11ba <u8charleni+0xba>
cmpl   $0x200000,-0x8(%rbp)
jge    1181 <u8charleni+0x81>
movl   $0x4,-0x4(%rbp)
jmp    11ba <u8charleni+0xba>
cmpl   $0x4000000,-0x8(%rbp)
jge    119a <u8charleni+0x9a>
movl   $0x5,-0x4(%rbp)
jmp    11ba <u8charleni+0xba>
cmpl   $0x80000000,-0x8(%rbp)
jae    11b3 <u8charleni+0xb3>
movl   $0x6,-0x4(%rbp)
jmp    11ba <u8charleni+0xba>
movl   $0x0,-0x4(%rbp)
mov    -0x4(%rbp),%eax
pop    %rbp
ret

x86 assembly (clang, -O2):
<u8charleni>:
test   %edi,%edi
jle    1147 <u8charleni+0x47>
mov    $0x1,%eax
cmp    $0x80,%edi
jb     1146 <u8charleni+0x46>
mov    $0x2,%eax
cmp    $0x800,%edi
jb     1146 <u8charleni+0x46>
mov    $0x3,%eax
cmp    $0x10000,%edi
jb     1146 <u8charleni+0x46>
mov    $0x4,%eax
cmp    $0x200000,%edi
jb     1146 <u8charleni+0x46>
cmp    $0x4000000,%edi
mov    $0x6,%eax
sbb    $0x0,%eax
ret
xor    %eax,%eax
ret

LLVM IR (-O0):
define i32 @u8charleni(i32 %0) {
%2 = alloca i32
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
%5 = icmp sle i32 %4, 0
br i1 %5, label %6, label %7
6: ; preds = %1
store i32 0, i32* %2
br label %32
7: ; preds = %1
%8 = load i32, i32* %3
%9 = icmp slt i32 %8, 128
br i1 %9, label %10, label %11
10: ; preds = %7
store i32 1, i32* %2
br label %32
11: ; preds = %7
%12 = load i32, i32* %3
%13 = icmp slt i32 %12, 2048
br i1 %13, label %14, label %15
14: ; preds = %11
store i32 2, i32* %2
br label %32
15: ; preds = %11
%16 = load i32, i32* %3
%17 = icmp slt i32 %16, 65536
br i1 %17, label %18, label %19
18: ; preds = %15
store i32 3, i32* %2
br label %32
19: ; preds = %15
%20 = load i32, i32* %3
%21 = icmp slt i32 %20, 2097152
br i1 %21, label %22, label %23
22: ; preds = %19
store i32 4, i32* %2
br label %32
23: ; preds = %19
%24 = load i32, i32* %3
%25 = icmp slt i32 %24, 67108864
br i1 %25, label %26, label %27
26: ; preds = %23
store i32 5, i32* %2
br label %32
27: ; preds = %23
%28 = load i32, i32* %3
%29 = icmp ult i32 %28, -2147483648
br i1 %29, label %30, label %31
30: ; preds = %27
store i32 6, i32* %2
br label %32
31: ; preds = %27
store i32 0, i32* %2
br label %32
32: ; preds = %31, %30, %26, %22, %18, %14, %10, %6
%33 = load i32, i32* %2
ret i32 %33
}

LLVM IR (-O2):
define i32 @u8charleni(i32 %0) {
%2 = icmp slt i32 %0, 1
br i1 %2, label %14, label %3
3: ; preds = %1
%4 = icmp ult i32 %0, 128
br i1 %4, label %14, label %5
5: ; preds = %3
%6 = icmp ult i32 %0, 2048
br i1 %6, label %14, label %7
7: ; preds = %5
%8 = icmp ult i32 %0, 65536
br i1 %8, label %14, label %9
9: ; preds = %7
%10 = icmp ult i32 %0, 2097152
br i1 %10, label %14, label %11
11: ; preds = %9
%12 = icmp ult i32 %0, 67108864
%13 = select i1 %12, i32 5, i32 6
br label %14
14: ; preds = %11, %9, %7, %5, %3, %1
%15 = phi i32 [ 0, %1 ], [ 1, %3 ], [ 2, %5 ], [ 3, %7 ], [ 4, %9 ], [ %13, %11 ]
ret i32 %15
}