void initialize_v_walls(int walls[25][25 - 1]) {
  int i, j;
  for (i = 0; i < 25; i++) {
    for (j = 0; j < 25 - 1; j++) {
      walls[i][j] = 1;
    }
  }
}


x86 assembly (clang, -O0):
<initialize_v_walls>:
push   %rbp
mov    %rsp,%rbp
mov    %rdi,-0x8(%rbp)
movl   $0x0,-0xc(%rbp)
cmpl   $0x19,-0xc(%rbp)
jge    1165 <initialize_v_walls+0x65>
movl   $0x0,-0x10(%rbp)
cmpl   $0x18,-0x10(%rbp)
jge    1152 <initialize_v_walls+0x52>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
imul   $0x60,%rcx,%rcx
add    %rcx,%rax
movslq -0x10(%rbp),%rcx
movl   $0x1,(%rax,%rcx,4)
mov    -0x10(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x10(%rbp)
jmp    1120 <initialize_v_walls+0x20>
jmp    1157 <initialize_v_walls+0x57>
mov    -0xc(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0xc(%rbp)
jmp    110f <initialize_v_walls+0xf>
pop    %rbp
ret

x86 assembly (clang, -O2):
<initialize_v_walls>:
mov    $0xb0,%eax
movaps 0xef4(%rip),%xmm0
nopl   0x0(%rax)
movups %xmm0,-0xb0(%rdi,%rax,1)
ff
movups %xmm0,-0xa0(%rdi,%rax,1)
ff
movups %xmm0,-0x90(%rdi,%rax,1)
ff
movups %xmm0,-0x80(%rdi,%rax,1)
movups %xmm0,-0x70(%rdi,%rax,1)
movups %xmm0,-0x60(%rdi,%rax,1)
cmp    $0x9b0,%rax
je     1164 <initialize_v_walls+0x64>
movups %xmm0,-0x50(%rdi,%rax,1)
movups %xmm0,-0x40(%rdi,%rax,1)
movups %xmm0,-0x30(%rdi,%rax,1)
movups %xmm0,-0x20(%rdi,%rax,1)
movups %xmm0,-0x10(%rdi,%rax,1)
movups %xmm0,(%rdi,%rax,1)
add    $0xc0,%rax
jmp    1110 <initialize_v_walls+0x10>
ret

LLVM IR (-O0):
define void @initialize_v_walls([24 x i32]* %0) {
%2 = alloca [24 x i32]*
%3 = alloca i32
%4 = alloca i32
store [24 x i32]* %0, [24 x i32]** %2
store i32 0, i32* %3
br label %5
5: ; preds = %24, %1
%6 = load i32, i32* %3
%7 = icmp slt i32 %6, 25
br i1 %7, label %8, label %27
8: ; preds = %5
store i32 0, i32* %4
br label %9
9: ; preds = %20, %8
%10 = load i32, i32* %4
%11 = icmp slt i32 %10, 24
br i1 %11, label %12, label %23
12: ; preds = %9
%13 = load [24 x i32]*, [24 x i32]** %2
%14 = load i32, i32* %3
%15 = sext i32 %14 to i64
%16 = getelementptr inbounds [24 x i32], [24 x i32]* %13, i64 %15
%17 = load i32, i32* %4
%18 = sext i32 %17 to i64
%19 = getelementptr inbounds [24 x i32], [24 x i32]* %16, i64 0, i64 %18
store i32 1, i32* %19
br label %20
20: ; preds = %12
%21 = load i32, i32* %4
%22 = add nsw i32 %21, 1
store i32 %22, i32* %4
br label %9
23: ; preds = %9
br label %24
24: ; preds = %23
%25 = load i32, i32* %3
%26 = add nsw i32 %25, 1
store i32 %26, i32* %3
br label %5
27: ; preds = %5
ret void
}

LLVM IR (-O2):
define void @initialize_v_walls([24 x i32]* nocapture writeonly %0) {
br label %2
2: ; preds = %18, %1
%3 = phi i64 [ 0, %1 ], [ %31, %18 ]
%4 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %3, i64 0
%5 = bitcast i32* %4 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %5
%6 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %3, i64 4
%7 = bitcast i32* %6 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %7
%8 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %3, i64 8
%9 = bitcast i32* %8 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %9
%10 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %3, i64 12
%11 = bitcast i32* %10 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %11
%12 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %3, i64 16
%13 = bitcast i32* %12 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %13
%14 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %3, i64 20
%15 = bitcast i32* %14 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %15
%16 = or i64 %3, 1
%17 = icmp eq i64 %16, 25
br i1 %17, label %32, label %18
18: ; preds = %2
%19 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %16, i64 0
%20 = bitcast i32* %19 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %20
%21 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %16, i64 4
%22 = bitcast i32* %21 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %22
%23 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %16, i64 8
%24 = bitcast i32* %23 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %24
%25 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %16, i64 12
%26 = bitcast i32* %25 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %26
%27 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %16, i64 16
%28 = bitcast i32* %27 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %28
%29 = getelementptr inbounds [24 x i32], [24 x i32]* %0, i64 %16, i64 20
%30 = bitcast i32* %29 to <4 x i32>*
store <4 x i32> <i32 1, i32 1, i32 1, i32 1>, <4 x i32>* %30
%31 = add nuw nsw i64 %3, 2
br label %2
32: ; preds = %2
ret void
}