#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 */
void *malloc(int);
int **alloc2d(int rows, int cols) {
  int **matrix = malloc(rows * (sizeof(int *)));
  int i = 0;
  for (; i < rows; i++) {
    matrix[i] = malloc(cols * (sizeof(int)));
  }
  return matrix;
}


x86 assembly (clang, -O0):
<alloc2d>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %edi,-0x4(%rbp)
mov    %esi,-0x8(%rbp)
movslq -0x4(%rbp),%rax
shl    $0x3,%rax
mov    %eax,%edi
call   1030 <malloc@plt>
mov    %rax,-0x10(%rbp)
movl   $0x0,-0x14(%rbp)
mov    -0x14(%rbp),%eax
cmp    -0x4(%rbp),%eax
jge    1170 <alloc2d+0x60>
movslq -0x8(%rbp),%rax
shl    $0x2,%rax
mov    %eax,%edi
call   1030 <malloc@plt>
mov    %rax,%rdx
mov    -0x10(%rbp),%rax
movslq -0x14(%rbp),%rcx
mov    %rdx,(%rax,%rcx,8)
mov    -0x14(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x14(%rbp)
jmp    1138 <alloc2d+0x28>
mov    -0x10(%rbp),%rax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<alloc2d>:
push   %rbp
push   %r15
push   %r14
push   %r12
push   %rbx
mov    %esi,%r15d
mov    %edi,%r14d
lea    0x0(,%r14,8),%edi
call   1030 <malloc@plt>
mov    %rax,%r12
test   %r14d,%r14d
jle    1155 <alloc2d+0x45>
shl    $0x2,%r15d
mov    %r14d,%ebp
xor    %ebx,%ebx
nopl   0x0(%rax)
mov    %r15d,%edi
call   1030 <malloc@plt>
mov    %rax,(%r12,%rbx,8)
add    $0x1,%rbx
cmp    %rbx,%rbp
jne    1140 <alloc2d+0x30>
mov    %r12,%rax
pop    %rbx
pop    %r12
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
define i32** @alloc2d(i32 %0, i32 %1) {
%3 = alloca i32
%4 = alloca i32
%5 = alloca i32**
%6 = alloca i32
store i32 %0, i32* %3
store i32 %1, i32* %4
%7 = load i32, i32* %3
%8 = sext i32 %7 to i64
%9 = mul i64 %8, 8
%10 = trunc i64 %9 to i32
%11 = call i8* @malloc(i32 %10)
%12 = bitcast i8* %11 to i32**
store i32** %12, i32*** %5
store i32 0, i32* %6
br label %13
13: ; preds = %28, %2
%14 = load i32, i32* %6
%15 = load i32, i32* %3
%16 = icmp slt i32 %14, %15
br i1 %16, label %17, label %31
17: ; preds = %13
%18 = load i32, i32* %4
%19 = sext i32 %18 to i64
%20 = mul i64 %19, 4
%21 = trunc i64 %20 to i32
%22 = call i8* @malloc(i32 %21)
%23 = bitcast i8* %22 to i32*
%24 = load i32**, i32*** %5
%25 = load i32, i32* %6
%26 = sext i32 %25 to i64
%27 = getelementptr inbounds i32*, i32** %24, i64 %26
store i32* %23, i32** %27
br label %28
28: ; preds = %17
%29 = load i32, i32* %6
%30 = add nsw i32 %29, 1
store i32 %30, i32* %6
br label %13
31: ; preds = %13
%32 = load i32**, i32*** %5
ret i32** %32
}

LLVM IR (-O2):
define noalias i32** @alloc2d(i32 %0, i32 %1) {
%3 = shl i32 %0, 3
%4 = tail call i8* @malloc(i32 %3)
%5 = bitcast i8* %4 to i32**
%6 = icmp sgt i32 %0, 0
br i1 %6, label %7, label %17
7: ; preds = %2
%8 = shl i32 %1, 2
%9 = zext i32 %0 to i64
br label %10
10: ; preds = %7, %10
%11 = phi i64 [ 0, %7 ], [ %15, %10 ]
%12 = tail call i8* @malloc(i32 %8)
%13 = getelementptr inbounds i32*, i32** %5, i64 %11
%14 = bitcast i32** %13 to i8**
store i8* %12, i8** %14
%15 = add nuw nsw i64 %11, 1
%16 = icmp eq i64 %15, %9
br i1 %16, label %17, label %10
17: ; preds = %10, %2
ret i32** %5
}