const char *adaptive_errmsg(int kflag) {
  switch (kflag) {
  case -1:
    return "singular jacobian encountered";
  case 1:
    return "stepsize is close to 0";
  case 2:
    return "Step size too small";
  case 3:
    return "Too many steps";
  case 4:
    return "exceeded MAXTRY in stiff";
  default:
    return "unknown Stiff error";
  }
}


x86 assembly (clang, -O0):
<adaptive_errmsg>:
push   %rbp
mov    %rsp,%rbp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
add    $0x1,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x5,%eax
ja     1180 <adaptive_errmsg+0x80>
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    118b <adaptive_errmsg+0x8b>
lea    0xeef(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    118b <adaptive_errmsg+0x8b>
lea    0xef6(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    118b <adaptive_errmsg+0x8b>
lea    0xefa(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    118b <adaptive_errmsg+0x8b>
lea    0xef9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    118b <adaptive_errmsg+0x8b>
lea    0xf02(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
pop    %rbp
ret

x86 assembly (clang, -O2):
<adaptive_errmsg>:
add    $0x1,%edi
cmp    $0x5,%edi
ja     111a <adaptive_errmsg+0x1a>
movslq %edi,%rax
lea    0xf76(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
ret
lea    0xf50(%rip),%rax
ret

LLVM IR (-O0):
@.str = [30 x i8] c"singular jacobian encountered\00"
@.str.1 = [23 x i8] c"stepsize is close to 0\00"
@.str.2 = [20 x i8] c"Step size too small\00"
@.str.3 = [15 x i8] c"Too many steps\00"
@.str.4 = [25 x i8] c"exceeded MAXTRY in stiff\00"
@.str.5 = [20 x i8] c"unknown Stiff error\00"
define i8* @adaptive_errmsg(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %10 [
i32 -1, label %5
i32 1, label %6
i32 2, label %7
i32 3, label %8
i32 4, label %9
]
5: ; preds = %1
store i8* getelementptr inbounds ([30 x i8], [30 x i8]* @.str, i64 0, i64 0), i8** %2
br label %11
6: ; preds = %1
store i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %11
7: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %11
8: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %11
9: ; preds = %1
store i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.4, i64 0, i64 0), i8** %2
br label %11
10: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.5, i64 0, i64 0), i8** %2
br label %11
11: ; preds = %10, %9, %8, %7, %6, %5
%12 = load i8*, i8** %2
ret i8* %12
}

LLVM IR (-O2):
@.str = [30 x i8] c"singular jacobian encountered\00"
@.str.1 = [23 x i8] c"stepsize is close to 0\00"
@.str.2 = [20 x i8] c"Step size too small\00"
@.str.3 = [15 x i8] c"Too many steps\00"
@.str.4 = [25 x i8] c"exceeded MAXTRY in stiff\00"
@.str.5 = [20 x i8] c"unknown Stiff error\00"
@reltable.adaptive_errmsg = [6 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([30 x i8]* @.str to i64), i64 ptrtoint ([6 x i32]* @reltable.adaptive_errmsg to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.5 to i64), i64 ptrtoint ([6 x i32]* @reltable.adaptive_errmsg to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([23 x i8]* @.str.1 to i64), i64 ptrtoint ([6 x i32]* @reltable.adaptive_errmsg to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.2 to i64), i64 ptrtoint ([6 x i32]* @reltable.adaptive_errmsg to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.3 to i64), i64 ptrtoint ([6 x i32]* @reltable.adaptive_errmsg to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([25 x i8]* @.str.4 to i64), i64 ptrtoint ([6 x i32]* @reltable.adaptive_errmsg to i64)) to i32)]
define i8* @adaptive_errmsg(i32 %0) {
%2 = add i32 %0, 1
%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.adaptive_errmsg to i8*), i64 %6)
br label %8
8: ; preds = %1, %4
%9 = phi i8* [ %7, %4 ], [ getelementptr inbounds ([20 x i8], [20 x i8]* @.str.5, i64 0, i64 0), %1 ]
ret i8* %9
}