#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 */
char *malloc(size_t const);
int /*<<< orphan*/ strcpy(char *, char const *);
size_t strlen(char const *);
char *make_env_entry(const char *a, const char *b) {
  const size_t alen = strlen(a), blen = strlen(b);
  const size_t tot = alen + 1 + blen;
  char *result = malloc(tot + 1);
  strcpy(result, a);
  result[alen] = '=';
  strcpy(result + alen + 1, b);
  result[tot] = '\0';
  return result;
}


x86 assembly (clang, -O0):
<make_env_entry>:
push   %rbp
mov    %rsp,%rbp
sub    $0x30,%rsp
mov    %rdi,-0x8(%rbp)
mov    %rsi,-0x10(%rbp)
mov    -0x8(%rbp),%rdi
call   1040 <strlen@plt>
mov    %rax,-0x18(%rbp)
mov    -0x10(%rbp),%rdi
call   1040 <strlen@plt>
mov    %rax,-0x20(%rbp)
mov    -0x18(%rbp),%rax
add    $0x1,%rax
add    -0x20(%rbp),%rax
mov    %rax,-0x28(%rbp)
mov    -0x28(%rbp),%rdi
add    $0x1,%rdi
call   1050 <malloc@plt>
mov    %rax,-0x30(%rbp)
mov    -0x30(%rbp),%rdi
mov    -0x8(%rbp),%rsi
call   1030 <strcpy@plt>
mov    -0x30(%rbp),%rax
mov    -0x18(%rbp),%rcx
movb   $0x3d,(%rax,%rcx,1)
mov    -0x30(%rbp),%rdi
add    -0x18(%rbp),%rdi
add    $0x1,%rdi
mov    -0x10(%rbp),%rsi
call   1030 <strcpy@plt>
mov    -0x30(%rbp),%rax
mov    -0x28(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x30(%rbp),%rax
add    $0x30,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<make_env_entry>:
push   %r15
push   %r14
push   %r13
push   %r12
push   %rbx
mov    %rsi,%r14
mov    %rdi,%r15
call   1040 <strlen@plt>
mov    %rax,%r12
mov    %r14,%rdi
call   1040 <strlen@plt>
lea    (%r12,%rax,1),%r13
lea    (%r12,%rax,1),%rdi
add    $0x2,%rdi
call   1050 <malloc@plt>
mov    %rax,%rbx
mov    %rax,%rdi
mov    %r15,%rsi
call   1030 <strcpy@plt>
movb   $0x3d,(%rbx,%r12,1)
lea    (%rbx,%r12,1),%rdi
add    $0x1,%rdi
mov    %r14,%rsi
call   1030 <strcpy@plt>
movb   $0x0,0x1(%rbx,%r13,1)
mov    %rbx,%rax
pop    %rbx
pop    %r12
pop    %r13
pop    %r14
pop    %r15
ret

LLVM IR (-O0):
define i8* @make_env_entry(i8* %0, i8* %1) {
%3 = alloca i8*
%4 = alloca i8*
%5 = alloca i64
%6 = alloca i64
%7 = alloca i64
%8 = alloca i8*
store i8* %0, i8** %3
store i8* %1, i8** %4
%9 = load i8*, i8** %3
%10 = call i64 @strlen(i8* %9)
store i64 %10, i64* %5
%11 = load i8*, i8** %4
%12 = call i64 @strlen(i8* %11)
store i64 %12, i64* %6
%13 = load i64, i64* %5
%14 = add i64 %13, 1
%15 = load i64, i64* %6
%16 = add i64 %14, %15
store i64 %16, i64* %7
%17 = load i64, i64* %7
%18 = add i64 %17, 1
%19 = call i8* @malloc(i64 %18)
store i8* %19, i8** %8
%20 = load i8*, i8** %8
%21 = load i8*, i8** %3
%22 = call i32 @strcpy(i8* %20, i8* %21)
%23 = load i8*, i8** %8
%24 = load i64, i64* %5
%25 = getelementptr inbounds i8, i8* %23, i64 %24
store i8 61, i8* %25
%26 = load i8*, i8** %8
%27 = load i64, i64* %5
%28 = getelementptr inbounds i8, i8* %26, i64 %27
%29 = getelementptr inbounds i8, i8* %28, i64 1
%30 = load i8*, i8** %4
%31 = call i32 @strcpy(i8* %29, i8* %30)
%32 = load i8*, i8** %8
%33 = load i64, i64* %7
%34 = getelementptr inbounds i8, i8* %32, i64 %33
store i8 0, i8* %34
%35 = load i8*, i8** %8
ret i8* %35
}

LLVM IR (-O2):
define i8* @make_env_entry(i8* %0, i8* %1) {
%3 = tail call i64 @strlen(i8* dereferenceable(1) %0)
%4 = tail call i64 @strlen(i8* dereferenceable(1) %1)
%5 = add i64 %3, 1
%6 = add i64 %5, %4
%7 = add i64 %6, 1
%8 = tail call i8* @malloc(i64 %7)
%9 = tail call i32 @strcpy(i8* %8, i8* %0)
%10 = getelementptr inbounds i8, i8* %8, i64 %3
store i8 61, i8* %10
%11 = getelementptr inbounds i8, i8* %10, i64 1
%12 = tail call i32 @strcpy(i8* %11, i8* %1)
%13 = getelementptr inbounds i8, i8* %8, i64 %6
store i8 0, i8* %13
ret i8* %8
}