const char *cobyla_reason(int status) {
  switch (status) {
  case (1):
    return "user requested to compute F(X) and C(X)";
  case (0):
    return "algorithm was successful";
  case (-1):
    return "rounding errors are becoming damaging";
  case (-2):
    return "MAXFUN limit has been reached";
  case (-3):
    return "illegal NULL address";
  case (-4):
    return "unexpected parameter or corrupted workspace";
  default:
    return "unknown status";
  }
}


x86 assembly (clang, -O0):
<cobyla_reason>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
add    $0x4,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x5,%eax
ja     1190 <cobyla_reason+0x90>
mov    -0x18(%rbp),%rax
lea    0xed9(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xee1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    119b <cobyla_reason+0x9b>
lea    0xef9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    119b <cobyla_reason+0x9b>
lea    0xf02(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    119b <cobyla_reason+0x9b>
lea    0xf18(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    119b <cobyla_reason+0x9b>
lea    0xf26(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    119b <cobyla_reason+0x9b>
lea    0xf2b(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    119b <cobyla_reason+0x9b>
lea    0xf47(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<cobyla_reason>:
add    $0x4,%edi
cmp    $0x5,%edi
ja     111a <cobyla_reason+0x1a>
movslq %edi,%rax
lea    0xfc6(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xfa5(%rip),%rax
ret

LLVM IR (-O0):
@.str = [40 x i8] c"user requested to compute F(X) and C(X)\00"
@.str.1 = [25 x i8] c"algorithm was successful\00"
@.str.2 = [38 x i8] c"rounding errors are becoming damaging\00"
@.str.3 = [30 x i8] c"MAXFUN limit has been reached\00"
@.str.4 = [21 x i8] c"illegal NULL address\00"
@.str.5 = [44 x i8] c"unexpected parameter or corrupted workspace\00"
@.str.6 = [15 x i8] c"unknown status\00"
define i8* @cobyla_reason(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %11 [
i32 1, label %5
i32 0, label %6
i32 -1, label %7
i32 -2, label %8
i32 -3, label %9
i32 -4, label %10
]
5: ; preds = %1
store i8* getelementptr inbounds ([40 x i8], [40 x i8]* @.str, i64 0, i64 0), i8** %2
br label %12
6: ; preds = %1
store i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %12
7: ; preds = %1
store i8* getelementptr inbounds ([38 x i8], [38 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %12
8: ; preds = %1
store i8* getelementptr inbounds ([30 x i8], [30 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %12
9: ; preds = %1
store i8* getelementptr inbounds ([21 x i8], [21 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %12
10: ; preds = %1
store i8* getelementptr inbounds ([44 x i8], [44 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %12
11: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.6, i64 0, i64 0), i8** %2
br label %12
12: ; preds = %11, %10, %9, %8, %7, %6, %5
%13 = load i8*, i8** %2
ret i8* %13
}

LLVM IR (-O2):
@.str = [40 x i8] c"user requested to compute F(X) and C(X)\00"
@.str.1 = [25 x i8] c"algorithm was successful\00"
@.str.2 = [38 x i8] c"rounding errors are becoming damaging\00"
@.str.3 = [30 x i8] c"MAXFUN limit has been reached\00"
@.str.4 = [21 x i8] c"illegal NULL address\00"
@.str.5 = [44 x i8] c"unexpected parameter or corrupted workspace\00"
@.str.6 = [15 x i8] c"unknown status\00"
@reltable.cobyla_reason = [6 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([44 x i8]* @.str.5 to i64), i64 ptrtoint ([6 x i32]* @reltable.cobyla_reason to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([21 x i8]* @.str.4 to i64), i64 ptrtoint ([6 x i32]* @reltable.cobyla_reason to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([30 x i8]* @.str.3 to i64), i64 ptrtoint ([6 x i32]* @reltable.cobyla_reason to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([38 x i8]* @.str.2 to i64), i64 ptrtoint ([6 x i32]* @reltable.cobyla_reason to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([25 x i8]* @.str.1 to i64), i64 ptrtoint ([6 x i32]* @reltable.cobyla_reason to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([40 x i8]* @.str to i64), i64 ptrtoint ([6 x i32]* @reltable.cobyla_reason to i64)) to i32)]
define i8* @cobyla_reason(i32 %0) {
%2 = add i32 %0, 4
%3 = icmp ult i32 %2, 6
br i1 %3, label %4, label %8
4: ; preds = %1
%5 = sext i32 %2 to i64
%6 = shl i64 %5, 2
%7 = call i8* @llvm.load.relative.i64(i8* bitcast ([6 x i32]* @reltable.cobyla_reason to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([15 x i8], [15 x i8]* @.str.6, i64 0, i64 0), %1 ]
ret i8* %9
}