const char *y4m_strerr(int err) {
  switch (err) {
  case 0:
    return "no error";
  case 1:
    return "parameter out of range";
  case 2:
    return "stream ended unexpectedly (failed read/write)";
  case 3:
    return "bad stream or frame header";
  case 4:
    return "unknown header tag";
  case 5:
    return "bad header magic";
  case 7:
    return "too many xtags";
  case 6:
    return "end-of-file";
  default:
    return "unknown error code";
  }
}


x86 assembly (clang, -O0):
<y4m_strerr>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0x7,%rax
ja     11ac <y4m_strerr+0xac>
mov    -0x18(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xeed(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xee6(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xeed(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xf0b(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xf16(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xf19(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xf1a(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xf19(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11b7 <y4m_strerr+0xb7>
lea    0xf15(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<y4m_strerr>:
cmp    $0x7,%edi
ja     1117 <y4m_strerr+0x17>
movslq %edi,%rax
lea    0xfad(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf8a(%rip),%rax
ret

LLVM IR (-O0):
@.str = [9 x i8] c"no error\00"
@.str.1 = [23 x i8] c"parameter out of range\00"
@.str.2 = [46 x i8] c"stream ended unexpectedly (failed read/write)\00"
@.str.3 = [27 x i8] c"bad stream or frame header\00"
@.str.4 = [19 x i8] c"unknown header tag\00"
@.str.5 = [17 x i8] c"bad header magic\00"
@.str.6 = [15 x i8] c"too many xtags\00"
@.str.7 = [12 x i8] c"end-of-file\00"
@.str.8 = [19 x i8] c"unknown error code\00"
define i8* @y4m_strerr(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %13 [
i32 0, label %5
i32 1, label %6
i32 2, label %7
i32 3, label %8
i32 4, label %9
i32 5, label %10
i32 7, label %11
i32 6, label %12
]
5: ; preds = %1
store i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i64 0, i64 0), i8** %2
br label %14
6: ; preds = %1
store i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %14
7: ; preds = %1
store i8* getelementptr inbounds ([46 x i8], [46 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %14
8: ; preds = %1
store i8* getelementptr inbounds ([27 x i8], [27 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %14
9: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %14
10: ; preds = %1
store i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %14
11: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %14
12: ; preds = %1
store i8* getelementptr inbounds ([12 x i8], [12 x i8]* @.str.7, i64 0, i64 0), i8** %2
br label %14
13: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.8, i64 0, i64 0), i8** %2
br label %14
14: ; preds = %13, %12, %11, %10, %9, %8, %7, %6, %5
%15 = load i8*, i8** %2
ret i8* %15
}

LLVM IR (-O2):
@.str = [9 x i8] c"no error\00"
@.str.1 = [23 x i8] c"parameter out of range\00"
@.str.2 = [46 x i8] c"stream ended unexpectedly (failed read/write)\00"
@.str.3 = [27 x i8] c"bad stream or frame header\00"
@.str.4 = [19 x i8] c"unknown header tag\00"
@.str.5 = [17 x i8] c"bad header magic\00"
@.str.6 = [15 x i8] c"too many xtags\00"
@.str.7 = [12 x i8] c"end-of-file\00"
@.str.8 = [19 x i8] c"unknown error code\00"
@reltable.y4m_strerr = [8 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([9 x i8]* @.str to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([23 x i8]* @.str.1 to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([46 x i8]* @.str.2 to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([27 x i8]* @.str.3 to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.4 to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([17 x i8]* @.str.5 to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([12 x i8]* @.str.7 to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.6 to i64), i64 ptrtoint ([8 x i32]* @reltable.y4m_strerr to i64)) to i32)]
define i8* @y4m_strerr(i32 %0) {
%2 = icmp ult i32 %0, 8
br i1 %2, label %3, label %7
3: ; preds = %1
%4 = sext i32 %0 to i64
%5 = shl i64 %4, 2
%6 = call i8* @llvm.load.relative.i64(i8* bitcast ([8 x i32]* @reltable.y4m_strerr to i8*), i64 %5)
br label %7
7: ; preds = %1, %3
%8 = phi i8* [ %6, %3 ], [ getelementptr inbounds ([19 x i8], [19 x i8]* @.str.8, i64 0, i64 0), %1 ]
ret i8* %8
}