#define NULL ((void *)0)
typedef unsigned long size_t; // Customize by platform.
typedef long intptr_t;
typedef unsigned long uintptr_t;
typedef long scalar_t__; // Either arithmetic or pointer type.
/* By default, we understand bool (as a convenience). */
typedef int bool;
#define false 0
#define true 1

/* Forward declarations */

/* Type definitions */

/* Variables and functions */
#define EBADF 132
#define EINVAL 131
#define ENOENT 130
#define ENOSYS 129
#define ESRCH 128
int /*<<< orphan*/ sprintf(char *, char *, int);
char *strerror(int errnum) {
  static char msgbuf[100];
  char *msg;
  switch (errnum) {
  case ENOSYS:
    msg = "Function not supported";
    break;
  case EINVAL:
    msg = "Invalid argument";
    break;
  case EBADF:
    msg = "Bad file descriptor";
    break;
  case ESRCH:
    msg = "No such process";
    break;
  case ENOENT:
    msg = "File not found";
    break;
  default:
    sprintf(msgbuf, "Undefined error %d", errnum);
    msg = msgbuf;
    break;
  }
  return msg;
}


x86 assembly (clang, -O0):
<strerror>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0xffffff80,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x4,%eax
ja     1194 <strerror+0x84>
mov    -0x18(%rbp),%rax
lea    0xec5(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xec9(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11b5 <strerror+0xa5>
lea    0xed0(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11b5 <strerror+0xa5>
lea    0xed1(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11b5 <strerror+0xa5>
lea    0xed5(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11b5 <strerror+0xa5>
lea    0xed5(%rip),%rax
mov    %rax,-0x10(%rbp)
jmp    11b5 <strerror+0xa5>
mov    -0x4(%rbp),%edx
lea    0x2ea2(%rip),%rdi
lea    0xeca(%rip),%rsi
call   1030 <sprintf@plt>
lea    0x2e8f(%rip),%rax
mov    %rax,-0x10(%rbp)
mov    -0x10(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<strerror>:
push   %rbx
mov    %edi,%edx
lea    -0x80(%rdx),%eax
cmp    $0x5,%eax
jae    112d <strerror+0x1d>
cltq
lea    0xf4c(%rip),%rcx
movslq (%rcx,%rax,4),%rbx
add    %rcx,%rbx
jmp    1143 <strerror+0x33>
lea    0x2f0c(%rip),%rbx
lea    0xf20(%rip),%rsi
mov    %rbx,%rdi
call   1030 <sprintf@plt>
mov    %rbx,%rax
pop    %rbx
ret

LLVM IR (-O0):
@strerror.msgbuf = internal global [100 x i8] zeroinitializer
@.str = [23 x i8] c"Function not supported\00"
@.str.1 = [17 x i8] c"Invalid argument\00"
@.str.2 = [20 x i8] c"Bad file descriptor\00"
@.str.3 = [16 x i8] c"No such process\00"
@.str.4 = [15 x i8] c"File not found\00"
@.str.5 = [19 x i8] c"Undefined error %d\00"
define i8* @strerror(i32 %0) {
%2 = alloca i32
%3 = alloca i8*
store i32 %0, i32* %2
%4 = load i32, i32* %2
switch i32 %4, label %10 [
i32 129, label %5
i32 131, label %6
i32 132, label %7
i32 128, label %8
i32 130, label %9
]
5: ; preds = %1
store i8* getelementptr inbounds ([23 x i8], [23 x i8]* @.str, i64 0, i64 0), i8** %3
br label %13
6: ; preds = %1
store i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str.1, i64 0, i64 0), i8** %3
br label %13
7: ; preds = %1
store i8* getelementptr inbounds ([20 x i8], [20 x i8]* @.str.2, i64 0, i64 0), i8** %3
br label %13
8: ; preds = %1
store i8* getelementptr inbounds ([16 x i8], [16 x i8]* @.str.3, i64 0, i64 0), i8** %3
br label %13
9: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.4, i64 0, i64 0), i8** %3
br label %13
10: ; preds = %1
%11 = load i32, i32* %2
%12 = call i32 @sprintf(i8* getelementptr inbounds ([100 x i8], [100 x i8]* @strerror.msgbuf, i64 0, i64 0), i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.5, i64 0, i64 0), i32 %11)
store i8* getelementptr inbounds ([100 x i8], [100 x i8]* @strerror.msgbuf, i64 0, i64 0), i8** %3
br label %13
13: ; preds = %10, %9, %8, %7, %6, %5
%14 = load i8*, i8** %3
ret i8* %14
}

LLVM IR (-O2):
@strerror.msgbuf = internal global [100 x i8] zeroinitializer
@.str = [23 x i8] c"Function not supported\00"
@.str.1 = [17 x i8] c"Invalid argument\00"
@.str.2 = [20 x i8] c"Bad file descriptor\00"
@.str.3 = [16 x i8] c"No such process\00"
@.str.4 = [15 x i8] c"File not found\00"
@.str.5 = [19 x i8] c"Undefined error %d\00"
@reltable.strerror = [5 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([16 x i8]* @.str.3 to i64), i64 ptrtoint ([5 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([23 x i8]* @.str to i64), i64 ptrtoint ([5 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.4 to i64), i64 ptrtoint ([5 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([17 x i8]* @.str.1 to i64), i64 ptrtoint ([5 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([20 x i8]* @.str.2 to i64), i64 ptrtoint ([5 x i32]* @reltable.strerror to i64)) to i32)]
define i8* @strerror(i32 %0) {
%2 = add i32 %0, -128
%3 = icmp ult i32 %2, 5
br i1 %3, label %6, label %4
4: ; preds = %1
%5 = tail call i32 @sprintf(i8* dereferenceable(1) getelementptr inbounds ([100 x i8], [100 x i8]* @strerror.msgbuf, i64 0, i64 0), i8* dereferenceable(1) getelementptr inbounds ([19 x i8], [19 x i8]* @.str.5, i64 0, i64 0), i32 %0)
br label %10
6: ; preds = %1
%7 = sext i32 %2 to i64
%8 = shl i64 %7, 2
%9 = call i8* @llvm.load.relative.i64(i8* bitcast ([5 x i32]* @reltable.strerror to i8*), i64 %8)
br label %10
10: ; preds = %6, %4
%11 = phi i8* [ getelementptr inbounds ([100 x i8], [100 x i8]* @strerror.msgbuf, i64 0, i64 0), %4 ], [ %9, %6 ]
ret i8* %11
}