#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 */
int /*<<< orphan*/ printf(char *, ...);
int callback(void *user_data, int argc, char **argv, char **colname) {
  int i;
  for (i = 0; i < argc; i++) {
    printf("%s = %s\n", colname[i], argv[i] ? argv[i] : "NULL");
  }
  printf("\n");
  return 0;
}


x86 assembly (clang, -O0):
<callback>:
push   %rbp
mov    %rsp,%rbp
sub    $0x40,%rsp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
mov    %rdx,-0x18(%rbp)
mov    %rcx,-0x20(%rbp)
movl   $0x0,-0x24(%rbp)
mov    -0x24(%rbp),%eax
cmp    -0xc(%rbp),%eax
jge    11a6 <callback+0x96>
mov    -0x20(%rbp),%rax
movslq -0x24(%rbp),%rcx
mov    (%rax,%rcx,8),%rax
mov    %rax,-0x30(%rbp)
mov    -0x18(%rbp),%rax
movslq -0x24(%rbp),%rcx
cmpq   $0x0,(%rax,%rcx,8)
je     1172 <callback+0x62>
mov    -0x18(%rbp),%rax
movslq -0x24(%rbp),%rcx
mov    (%rax,%rcx,8),%rax
mov    %rax,-0x38(%rbp)
jmp    1182 <callback+0x72>
lea    0xe90(%rip),%rax
mov    %rax,-0x38(%rbp)
jmp    1182 <callback+0x72>
mov    -0x30(%rbp),%rsi
mov    -0x38(%rbp),%rdx
lea    0xe6f(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
mov    -0x24(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x24(%rbp)
jmp    112e <callback+0x1e>
lea    0xe5a(%rip),%rdi
mov    $0x0,%al
call   1030 <printf@plt>
xor    %eax,%eax
add    $0x40,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<callback>:
push   %rbp
push   %r15
push   %r14
push   %r13
push   %r12
push   %rbx
push   %rax
test   %esi,%esi
jle    1172 <callback+0x52>
mov    %rcx,%r14
mov    %rdx,%r12
mov    %esi,%ebx
lea    0xecb(%rip),%r13
lea    0xebb(%rip),%r15
xor    %ebp,%ebp
nopw   0x0(%rax,%rax,1)
mov    (%r14,%rbp,8),%rsi
mov    (%r12,%rbp,8),%rdx
test   %rdx,%rdx
cmove  %r13,%rdx
mov    %r15,%rdi
xor    %eax,%eax
call   1040 <printf@plt>
add    $0x1,%rbp
cmp    %rbp,%rbx
jne    1150 <callback+0x30>
mov    $0xa,%edi
call   1030 <putchar@plt>
xor    %eax,%eax
add    $0x8,%rsp
pop    %rbx
pop    %r12
pop    %r13
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
@.str = [9 x i8] c"%s = %s\0A\00"
@.str.1 = [5 x i8] c"NULL\00"
@.str.2 = [2 x i8] c"\0A\00"
define i32 @callback(i8* %0, i32 %1, i8** %2, i8** %3) {
%5 = alloca i8*
%6 = alloca i32
%7 = alloca i8**
%8 = alloca i8**
%9 = alloca i32
store i8* %0, i8** %5
store i32 %1, i32* %6
store i8** %2, i8*** %7
store i8** %3, i8*** %8
store i32 0, i32* %9
br label %10
10: ; preds = %36, %4
%11 = load i32, i32* %9
%12 = load i32, i32* %6
%13 = icmp slt i32 %11, %12
br i1 %13, label %14, label %39
14: ; preds = %10
%15 = load i8**, i8*** %8
%16 = load i32, i32* %9
%17 = sext i32 %16 to i64
%18 = getelementptr inbounds i8*, i8** %15, i64 %17
%19 = load i8*, i8** %18
%20 = load i8**, i8*** %7
%21 = load i32, i32* %9
%22 = sext i32 %21 to i64
%23 = getelementptr inbounds i8*, i8** %20, i64 %22
%24 = load i8*, i8** %23
%25 = icmp ne i8* %24, null
br i1 %25, label %26, label %32
26: ; preds = %14
%27 = load i8**, i8*** %7
%28 = load i32, i32* %9
%29 = sext i32 %28 to i64
%30 = getelementptr inbounds i8*, i8** %27, i64 %29
%31 = load i8*, i8** %30
br label %33
32: ; preds = %14
br label %33
33: ; preds = %32, %26
%34 = phi i8* [ %31, %26 ], [ getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), %32 ]
%35 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i64 0, i64 0), i8* %19, i8* %34)
br label %36
36: ; preds = %33
%37 = load i32, i32* %9
%38 = add nsw i32 %37, 1
store i32 %38, i32* %9
br label %10
39: ; preds = %10
%40 = call i32 (i8*, ...) @printf(i8* getelementptr inbounds ([2 x i8], [2 x i8]* @.str.2, i64 0, i64 0))
ret i32 0
}

LLVM IR (-O2):
@.str = [9 x i8] c"%s = %s\0A\00"
@.str.1 = [5 x i8] c"NULL\00"
define i32 @callback(i8* nocapture readnone %0, i32 %1, i8** nocapture %2, i8** nocapture %3) {
%5 = icmp sgt i32 %1, 0
br i1 %5, label %6, label %19
6: ; preds = %4
%7 = zext i32 %1 to i64
br label %8
8: ; preds = %6, %8
%9 = phi i64 [ 0, %6 ], [ %17, %8 ]
%10 = getelementptr inbounds i8*, i8** %3, i64 %9
%11 = load i8*, i8** %10
%12 = getelementptr inbounds i8*, i8** %2, i64 %9
%13 = load i8*, i8** %12
%14 = icmp eq i8* %13, null
%15 = select i1 %14, i8* getelementptr inbounds ([5 x i8], [5 x i8]* @.str.1, i64 0, i64 0), i8* %13
%16 = tail call i32 (i8*, ...) @printf(i8* dereferenceable(1) getelementptr inbounds ([9 x i8], [9 x i8]* @.str, i64 0, i64 0), i8* %11, i8* %15)
%17 = add nuw nsw i64 %9, 1
%18 = icmp eq i64 %17, %7
br i1 %18, label %19, label %8
19: ; preds = %8, %4
%20 = tail call i32 @putchar(i32 10)
ret i32 0
}