char *btesh2_print_NameForFRegID(int id) {
  char *s;
  switch (id) {
  case 0:
    s = "FR1";
    break;
  case 1:
    s = "FR0";
    break;
  case 2:
    s = "FR3";
    break;
  case 3:
    s = "FR2";
    break;
  case 4:
    s = "FR5";
    break;
  case 5:
    s = "FR4";
    break;
  case 6:
    s = "FR7";
    break;
  case 7:
    s = "FR6";
    break;
  case 8:
    s = "FR9";
    break;
  case 9:
    s = "FR8";
    break;
  case 10:
    s = "FR11";
    break;
  case 11:
    s = "FR10";
    break;
  case 12:
    s = "FR13";
    break;
  case 13:
    s = "FR12";
    break;
  case 14:
    s = "FR15";
    break;
  case 15:
    s = "FR14";
    break;
  default:
    s = "?";
    break;
  }
  return (s);
}


x86 assembly (clang, -O0):
<btesh2_print_NameForFRegID>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0x4(%rbp)
mov    -0x4(%rbp),%eax
mov    %rax,-0x18(%rbp)
sub    $0xf,%rax
ja     122c <btesh2_print_NameForFRegID+0x12c>
mov    -0x18(%rbp),%rax
lea    0xedd(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xf0d(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xf01(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xef5(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xee9(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xedd(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xed1(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xec5(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xeb9(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xead(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xea1(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xe95(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xe8a(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xe7f(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xe74(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xe69(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xe5e(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    1237 <btesh2_print_NameForFRegID+0x137>
lea    0xe53(%rip),%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<btesh2_print_NameForFRegID>:
cmp    $0xf,%edi
ja     1117 <btesh2_print_NameForFRegID+0x17>
movslq %edi,%rax
lea    0xf39(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf28(%rip),%rax
ret

LLVM IR (-O0):
@.str = [4 x i8] c"FR1\00"
@.str.1 = [4 x i8] c"FR0\00"
@.str.2 = [4 x i8] c"FR3\00"
@.str.3 = [4 x i8] c"FR2\00"
@.str.4 = [4 x i8] c"FR5\00"
@.str.5 = [4 x i8] c"FR4\00"
@.str.6 = [4 x i8] c"FR7\00"
@.str.7 = [4 x i8] c"FR6\00"
@.str.8 = [4 x i8] c"FR9\00"
@.str.9 = [4 x i8] c"FR8\00"
@.str.10 = [5 x i8] c"FR11\00"
@.str.11 = [5 x i8] c"FR10\00"
@.str.12 = [5 x i8] c"FR13\00"
@.str.13 = [5 x i8] c"FR12\00"
@.str.14 = [5 x i8] c"FR15\00"
@.str.15 = [5 x i8] c"FR14\00"
@.str.16 = [2 x i8] c"?\00"
define i8* @btesh2_print_NameForFRegID(i32 %0) {
%2 = alloca i32
%3 = alloca i8*
store i32 %0, i32* %2
%4 = load i32, i32* %2
switch i32 %4, label %21 [
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 6, label %11
i32 7, label %12
i32 8, label %13
i32 9, label %14
i32 10, label %15
i32 11, label %16
i32 12, label %17
i32 13, label %18
i32 14, label %19
i32 15, label %20
]
5: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str, i64 0, i64 0), i8** %3
br label %22
6: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.1, i64 0, i64 0), i8** %3
br label %22
7: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.2, i64 0, i64 0), i8** %3
br label %22
8: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.3, i64 0, i64 0), i8** %3
br label %22
9: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.4, i64 0, i64 0), i8** %3
br label %22
10: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.5, i64 0, i64 0), i8** %3
br label %22
11: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.6, i64 0, i64 0), i8** %3
br label %22
12: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.7, i64 0, i64 0), i8** %3
br label %22
13: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.8, i64 0, i64 0), i8** %3
br label %22
14: ; preds = %1
store i8* getelementptr inbounds ([4 x i8], [4 x i8]* @.str.9, i64 0, i64 0), i8** %3
br label %22
15: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.10, i64 0, i64 0), i8** %3
br label %22
16: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.11, i64 0, i64 0), i8** %3
br label %22
17: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.12, i64 0, i64 0), i8** %3
br label %22
18: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.13, i64 0, i64 0), i8** %3
br label %22
19: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.14, i64 0, i64 0), i8** %3
br label %22
20: ; preds = %1
store i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.15, i64 0, i64 0), i8** %3
br label %22
21: ; preds = %1
store i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.16, i64 0, i64 0), i8** %3
br label %22
22: ; preds = %21, %20, %19, %18, %17, %16, %15, %14, %13, %12, %11, %10, %9, %8, %7, %6, %5
%23 = load i8*, i8** %3
ret i8* %23
}

LLVM IR (-O2):
@.str = [4 x i8] c"FR1\00"
@.str.1 = [4 x i8] c"FR0\00"
@.str.2 = [4 x i8] c"FR3\00"
@.str.3 = [4 x i8] c"FR2\00"
@.str.4 = [4 x i8] c"FR5\00"
@.str.5 = [4 x i8] c"FR4\00"
@.str.6 = [4 x i8] c"FR7\00"
@.str.7 = [4 x i8] c"FR6\00"
@.str.8 = [4 x i8] c"FR9\00"
@.str.9 = [4 x i8] c"FR8\00"
@.str.10 = [5 x i8] c"FR11\00"
@.str.11 = [5 x i8] c"FR10\00"
@.str.12 = [5 x i8] c"FR13\00"
@.str.13 = [5 x i8] c"FR12\00"
@.str.14 = [5 x i8] c"FR15\00"
@.str.15 = [5 x i8] c"FR14\00"
@.str.16 = [2 x i8] c"?\00"
@reltable.btesh2_print_NameForFRegID = [16 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.1 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.2 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.3 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.4 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.5 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.6 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.7 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.8 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([4 x i8]* @.str.9 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.10 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.11 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.12 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.13 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.14 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([5 x i8]* @.str.15 to i64), i64 ptrtoint ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i64)) to i32)]
define i8* @btesh2_print_NameForFRegID(i32 %0) {
%2 = icmp ult i32 %0, 16
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 ([16 x i32]* @reltable.btesh2_print_NameForFRegID to i8*), i64 %5)
br label %7
7: ; preds = %1, %3
%8 = phi i8* [ %6, %3 ], [ getelementptr inbounds ([2 x i8], [2 x i8]* @.str.16, i64 0, i64 0), %1 ]
ret i8* %8
}