int strcoll(const char *s1, const char *s2) {
  unsigned char coll[256] = {
      0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08, 0x09, 0x0a, 0x0b,
      0x0c, 0x0d, 0x0e, 0x0f, 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
      0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f, 0x20, 0x21, 0x22, 0x23,
      0x24, 0x25, 0x26, 0x27, 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
      0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39, 0x3a, 0x3b,
      0x3c, 0x3d, 0x3e, 0x3f, 0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
      0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f, 0x50, 0x51, 0x52, 0x53,
      0x54, 0x55, 0x56, 0x57, 0x58, 0x59, 0x5a, 0x5b, 0x5c, 0x5d, 0x5e, 0x5f,
      0x60, 0x61, 0x62, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69, 0x6a, 0x6b,
      0x6c, 0x6d, 0x6e, 0x6f, 0x70, 0x71, 0x72, 0x73, 0x74, 0x75, 0x76, 0x77,
      0x78, 0x79, 0x7a, 0x7b, 0x7c, 0x7d, 0x7e, 0x7f, 0x80, 0x81, 0x82, 0x83,
      0x84, 0x85, 0x86, 0x87, 0x88, 0x89, 0x8a, 0x8b, 0x8c, 0x8d, 0x8e, 0x8f,
      0x90, 0x91, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98, 0x99, 0x9a, 0x9b,
      0x9c, 0x9d, 0x9e, 0x9f, 0xa0, 0xa1, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
      0xa8, 0xa9, 0xaa, 0xab, 0xac, 0xad, 0xae, 0xaf, 0xb0, 0xb1, 0xb2, 0xb3,
      0xb4, 0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xbb, 0xbc, 0xbd, 0xbe, 0xbf,
      0xc0, 0xc1, 0xc2, 0xc3, 0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xcb,
      0xcc, 0xcd, 0xce, 0xcf, 0xd0, 0xd1, 0xd2, 0xd3, 0xd4, 0xd5, 0xd6, 0xd7,
      0xd8, 0xd9, 0xda, 0xdb, 0xdc, 0xdd, 0xde, 0xdf, 0xe0, 0xe1, 0xe2, 0xe3,
      0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea, 0xeb, 0xec, 0xed, 0xee, 0xef,
      0xf0, 0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8, 0xf9, 0xfa, 0xfb,
      0xfc, 0xfd, 0xfe, 0xff};
  while (coll[(unsigned char)*s1] == coll[(unsigned char)*s2]) {
    if (*s1 == 0)
      return 0;
    s1++, s2++;
  }
  return coll[(unsigned char)*s1] - coll[(unsigned char)*s2];
}


x86 assembly (clang, -O0):
<strcoll>:
push   %rbp
mov    %rsp,%rbp
sub    $0x120,%rsp
mov    %rdi,-0x10(%rbp)
mov    %rsi,-0x18(%rbp)
lea    -0x120(%rbp),%rdi
lea    0xecf(%rip),%rsi
mov    $0x100,%edx
call   1030 <memcpy@plt>
mov    -0x10(%rbp),%rax
movzbl (%rax),%eax
movzbl -0x120(%rbp,%rax,1),%eax
ff
mov    -0x18(%rbp),%rcx
movzbl (%rcx),%ecx
movzbl -0x120(%rbp,%rcx,1),%ecx
ff
cmp    %ecx,%eax
jne    119a <strcoll+0x8a>
mov    -0x10(%rbp),%rax
movsbl (%rax),%eax
cmp    $0x0,%eax
jne    117d <strcoll+0x6d>
movl   $0x0,-0x4(%rbp)
jmp    11bd <strcoll+0xad>
mov    -0x10(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x10(%rbp)
mov    -0x18(%rbp),%rax
add    $0x1,%rax
mov    %rax,-0x18(%rbp)
jmp    113b <strcoll+0x2b>
mov    -0x10(%rbp),%rax
movzbl (%rax),%eax
movzbl -0x120(%rbp,%rax,1),%eax
ff
mov    -0x18(%rbp),%rcx
movzbl (%rcx),%ecx
movzbl -0x120(%rbp,%rcx,1),%ecx
ff
sub    %ecx,%eax
mov    %eax,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x120,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<strcoll>:
movzbl (%rdi),%ecx
lea    0xef6(%rip),%r8
mov    (%rcx,%r8,1),%r9b
movzbl (%rsi),%eax
mov    (%rax,%r8,1),%dl
cmp    %dl,%r9b
jne    113f <strcoll+0x3f>
mov    $0x1,%eax
nop
test   %cl,%cl
je     1149 <strcoll+0x49>
movzbl (%rdi,%rax,1),%ecx
movzbl (%rcx,%r8,1),%r9d
movzbl (%rsi,%rax,1),%edx
movzbl (%rdx,%r8,1),%edx
add    $0x1,%rax
cmp    %dl,%r9b
je     1120 <strcoll+0x20>
movzbl %dl,%ecx
movzbl %r9b,%eax
sub    %ecx,%eax
ret
xor    %eax,%eax
ret

LLVM IR (-O0):
@__const.strcoll.coll = [256 x i8] c"\00\01\02\03\04\05\06\07\08\09\0A\0B\0C\0D\0E\0F\10\11\12\13\14\15\16\17\18\19\1A\1B\1C\1D\1E\1F !\22#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\7F\80\81\82\83\84\85\86\87\88\89\8A\8B\8C\8D\8E\8F\90\91\92\93\94\95\96\97\98\99\9A\9B\9C\9D\9E\9F\A0\A1\A2\A3\A4\A5\A6\A7\A8\A9\AA\AB\AC\AD\AE\AF\B0\B1\B2\B3\B4\B5\B6\B7\B8\B9\BA\BB\BC\BD\BE\BF\C0\C1\C2\C3\C4\C5\C6\C7\C8\C9\CA\CB\CC\CD\CE\CF\D0\D1\D2\D3\D4\D5\D6\D7\D8\D9\DA\DB\DC\DD\DE\DF\E0\E1\E2\E3\E4\E5\E6\E7\E8\E9\EA\EB\EC\ED\EE\EF\F0\F1\F2\F3\F4\F5\F6\F7\F8\F9\FA\FB\FC\FD\FE\FF"
define i32 @strcoll(i8* %0, i8* %1) {
%3 = alloca i32
%4 = alloca i8*
%5 = alloca i8*
%6 = alloca [256 x i8]
store i8* %0, i8** %4
store i8* %1, i8** %5
%7 = bitcast [256 x i8]* %6 to i8*
br label %8
8: ; preds = %28, %2
%9 = load i8*, i8** %4
%10 = load i8, i8* %9
%11 = zext i8 %10 to i64
%12 = getelementptr inbounds [256 x i8], [256 x i8]* %6, i64 0, i64 %11
%13 = load i8, i8* %12
%14 = zext i8 %13 to i32
%15 = load i8*, i8** %5
%16 = load i8, i8* %15
%17 = zext i8 %16 to i64
%18 = getelementptr inbounds [256 x i8], [256 x i8]* %6, i64 0, i64 %17
%19 = load i8, i8* %18
%20 = zext i8 %19 to i32
%21 = icmp eq i32 %14, %20
br i1 %21, label %22, label %33
22: ; preds = %8
%23 = load i8*, i8** %4
%24 = load i8, i8* %23
%25 = sext i8 %24 to i32
%26 = icmp eq i32 %25, 0
br i1 %26, label %27, label %28
27: ; preds = %22
store i32 0, i32* %3
br label %47
28: ; preds = %22
%29 = load i8*, i8** %4
%30 = getelementptr inbounds i8, i8* %29, i32 1
store i8* %30, i8** %4
%31 = load i8*, i8** %5
%32 = getelementptr inbounds i8, i8* %31, i32 1
store i8* %32, i8** %5
br label %8
33: ; preds = %8
%34 = load i8*, i8** %4
%35 = load i8, i8* %34
%36 = zext i8 %35 to i64
%37 = getelementptr inbounds [256 x i8], [256 x i8]* %6, i64 0, i64 %36
%38 = load i8, i8* %37
%39 = zext i8 %38 to i32
%40 = load i8*, i8** %5
%41 = load i8, i8* %40
%42 = zext i8 %41 to i64
%43 = getelementptr inbounds [256 x i8], [256 x i8]* %6, i64 0, i64 %42
%44 = load i8, i8* %43
%45 = zext i8 %44 to i32
%46 = sub nsw i32 %39, %45
store i32 %46, i32* %3
br label %47
47: ; preds = %33, %27
%48 = load i32, i32* %3
ret i32 %48
}

LLVM IR (-O2):
@__const.strcoll.coll = [256 x i8] c"\00\01\02\03\04\05\06\07\08\09\0A\0B\0C\0D\0E\0F\10\11\12\13\14\15\16\17\18\19\1A\1B\1C\1D\1E\1F !\22#$%&'()*+,-./0123456789:;<=>?@ABCDEFGHIJKLMNOPQRSTUVWXYZ[\\]^_`abcdefghijklmnopqrstuvwxyz{|}~\7F\80\81\82\83\84\85\86\87\88\89\8A\8B\8C\8D\8E\8F\90\91\92\93\94\95\96\97\98\99\9A\9B\9C\9D\9E\9F\A0\A1\A2\A3\A4\A5\A6\A7\A8\A9\AA\AB\AC\AD\AE\AF\B0\B1\B2\B3\B4\B5\B6\B7\B8\B9\BA\BB\BC\BD\BE\BF\C0\C1\C2\C3\C4\C5\C6\C7\C8\C9\CA\CB\CC\CD\CE\CF\D0\D1\D2\D3\D4\D5\D6\D7\D8\D9\DA\DB\DC\DD\DE\DF\E0\E1\E2\E3\E4\E5\E6\E7\E8\E9\EA\EB\EC\ED\EE\EF\F0\F1\F2\F3\F4\F5\F6\F7\F8\F9\FA\FB\FC\FD\FE\FF"
define i32 @strcoll(i8* nocapture %0, i8* nocapture %1) {
%3 = load i8, i8* %0
%4 = zext i8 %3 to i64
%5 = getelementptr inbounds [256 x i8], [256 x i8]* @__const.strcoll.coll, i64 0, i64 %4
%6 = load i8, i8* %5
%7 = load i8, i8* %1
%8 = zext i8 %7 to i64
%9 = getelementptr inbounds [256 x i8], [256 x i8]* @__const.strcoll.coll, i64 0, i64 %8
%10 = load i8, i8* %9
%11 = icmp eq i8 %6, %10
br i1 %11, label %12, label %29
12: ; preds = %2, %17
%13 = phi i8 [ %20, %17 ], [ %3, %2 ]
%14 = phi i8* [ %19, %17 ], [ %1, %2 ]
%15 = phi i8* [ %18, %17 ], [ %0, %2 ]
%16 = icmp eq i8 %13, 0
br i1 %16, label %35, label %17
17: ; preds = %12
%18 = getelementptr inbounds i8, i8* %15, i64 1
%19 = getelementptr inbounds i8, i8* %14, i64 1
%20 = load i8, i8* %18
%21 = zext i8 %20 to i64
%22 = getelementptr inbounds [256 x i8], [256 x i8]* @__const.strcoll.coll, i64 0, i64 %21
%23 = load i8, i8* %22
%24 = load i8, i8* %19
%25 = zext i8 %24 to i64
%26 = getelementptr inbounds [256 x i8], [256 x i8]* @__const.strcoll.coll, i64 0, i64 %25
%27 = load i8, i8* %26
%28 = icmp eq i8 %23, %27
br i1 %28, label %12, label %29
29: ; preds = %17, %2
%30 = phi i8 [ %6, %2 ], [ %23, %17 ]
%31 = phi i8 [ %10, %2 ], [ %27, %17 ]
%32 = zext i8 %31 to i32
%33 = zext i8 %30 to i32
%34 = sub nsw i32 %33, %32
br label %35
35: ; preds = %12, %29
%36 = phi i32 [ %34, %29 ], [ 0, %12 ]
ret i32 %36
}