#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 EBUSY 133
#define ECANCELED 132
#define EINVAL 131
#define ENODEV 130
#define ENOMEM 129
#define ENOSYS 128
int errno;
int /*<<< orphan*/ snprintf(char *, int, char *, int);
char *strerror(int errnum) {
  static char unknown[18];
  switch (errnum) {
  case EINVAL:
    return "Invalid argument";
  case ENOSYS:
    return "Function not implemented";
  case ENODEV:
    return "No such device";
  case ECANCELED:
    return "Operation canceled";
  case EBUSY:
    return "Device or resource busy";
  case ENOMEM:
    return "Not enough space";
  }
  errno = EINVAL;
  snprintf(unknown, 18, "Unknown error %03d", errnum);
  return unknown;
}


x86 assembly (clang, -O0):
<strerror>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0xc(%rbp)
mov    -0xc(%rbp),%eax
add    $0xffffff80,%eax
mov    %eax,%ecx
mov    %rcx,-0x18(%rbp)
sub    $0x5,%eax
ja     11a4 <strerror+0x94>
mov    -0x18(%rbp),%rax
lea    0xec5(%rip),%rcx
movslq (%rcx,%rax,4),%rax
add    %rcx,%rax
jmp    *%rax
lea    0xecd(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11d7 <strerror+0xc7>
lea    0xece(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11d7 <strerror+0xc7>
lea    0xed7(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11d7 <strerror+0xc7>
lea    0xed6(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11d7 <strerror+0xc7>
lea    0xed9(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11d7 <strerror+0xc7>
lea    0xee1(%rip),%rax
mov    %rax,-0x8(%rbp)
jmp    11d7 <strerror+0xc7>
mov    0x2e35(%rip),%rax
movl   $0x83,(%rax)
mov    -0xc(%rbp),%ecx
lea    0x2e85(%rip),%rdi
mov    $0x12,%esi
lea    0xec6(%rip),%rdx
call   1030 <snprintf@plt>
lea    0x2e6d(%rip),%rax
mov    %rax,-0x8(%rbp)
mov    -0x8(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<strerror>:
push   %rbx
mov    %edi,%ecx
lea    -0x80(%rcx),%eax
cmp    $0x6,%eax
jae    112d <strerror+0x1d>
cltq
lea    0xf64(%rip),%rcx
movslq (%rcx,%rax,4),%rbx
add    %rcx,%rbx
jmp    1155 <strerror+0x45>
mov    0x2eac(%rip),%rax
movl   $0x83,(%rax)
lea    0x2eff(%rip),%rbx
lea    0xf2d(%rip),%rdx
mov    %rbx,%rdi
mov    $0x12,%esi
call   1030 <snprintf@plt>
mov    %rbx,%rax
pop    %rbx
ret

LLVM IR (-O0):
@strerror.unknown = internal global [18 x i8] zeroinitializer
@.str = [17 x i8] c"Invalid argument\00"
@.str.1 = [25 x i8] c"Function not implemented\00"
@.str.2 = [15 x i8] c"No such device\00"
@.str.3 = [19 x i8] c"Operation canceled\00"
@.str.4 = [24 x i8] c"Device or resource busy\00"
@.str.5 = [17 x i8] c"Not enough space\00"
@errno = global i32 0
@.str.6 = [19 x i8] c"Unknown error %03d\00"
define i8* @strerror(i32 %0) {
%2 = alloca i8*
%3 = alloca i32
store i32 %0, i32* %3
%4 = load i32, i32* %3
switch i32 %4, label %11 [
i32 131, label %5
i32 128, label %6
i32 130, label %7
i32 132, label %8
i32 133, label %9
i32 129, label %10
]
5: ; preds = %1
store i8* getelementptr inbounds ([17 x i8], [17 x i8]* @.str, i64 0, i64 0), i8** %2
br label %14
6: ; preds = %1
store i8* getelementptr inbounds ([25 x i8], [25 x i8]* @.str.1, i64 0, i64 0), i8** %2
br label %14
7: ; preds = %1
store i8* getelementptr inbounds ([15 x i8], [15 x i8]* @.str.2, i64 0, i64 0), i8** %2
br label %14
8: ; preds = %1
store i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.3, i64 0, i64 0), i8** %2
br label %14
9: ; preds = %1
store i8* getelementptr inbounds ([24 x i8], [24 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 i32 131, i32* @errno
%12 = load i32, i32* %3
%13 = call i32 @snprintf(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @strerror.unknown, i64 0, i64 0), i32 18, i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.6, i64 0, i64 0), i32 %12)
store i8* getelementptr inbounds ([18 x i8], [18 x i8]* @strerror.unknown, i64 0, i64 0), i8** %2
br label %14
14: ; preds = %11, %10, %9, %8, %7, %6, %5
%15 = load i8*, i8** %2
ret i8* %15
}

LLVM IR (-O2):
@strerror.unknown = internal global [18 x i8] zeroinitializer
@.str = [17 x i8] c"Invalid argument\00"
@.str.1 = [25 x i8] c"Function not implemented\00"
@.str.2 = [15 x i8] c"No such device\00"
@.str.3 = [19 x i8] c"Operation canceled\00"
@.str.4 = [24 x i8] c"Device or resource busy\00"
@.str.5 = [17 x i8] c"Not enough space\00"
@errno = global i32 0
@.str.6 = [19 x i8] c"Unknown error %03d\00"
@reltable.strerror = [6 x i32] [i32 trunc (i64 sub (i64 ptrtoint ([25 x i8]* @.str.1 to i64), i64 ptrtoint ([6 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([17 x i8]* @.str.5 to i64), i64 ptrtoint ([6 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([15 x i8]* @.str.2 to i64), i64 ptrtoint ([6 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([17 x i8]* @.str to i64), i64 ptrtoint ([6 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([19 x i8]* @.str.3 to i64), i64 ptrtoint ([6 x i32]* @reltable.strerror to i64)) to i32), i32 trunc (i64 sub (i64 ptrtoint ([24 x i8]* @.str.4 to i64), i64 ptrtoint ([6 x i32]* @reltable.strerror to i64)) to i32)]
define i8* @strerror(i32 %0) {
%2 = add i32 %0, -128
%3 = icmp ult i32 %2, 6
br i1 %3, label %6, label %4
4: ; preds = %1
store i32 131, i32* @errno
%5 = tail call i32 @snprintf(i8* getelementptr inbounds ([18 x i8], [18 x i8]* @strerror.unknown, i64 0, i64 0), i32 18, i8* getelementptr inbounds ([19 x i8], [19 x i8]* @.str.6, 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 ([6 x i32]* @reltable.strerror to i8*), i64 %8)
br label %10
10: ; preds = %6, %4
%11 = phi i8* [ getelementptr inbounds ([18 x i8], [18 x i8]* @strerror.unknown, i64 0, i64 0), %4 ], [ %9, %6 ]
ret i8* %11
}