#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 rand();
char *alea_chaine(char *chaine, int taille) {
  int i;
  for (i = 0; i < taille; ++i) {
    chaine[i] = rand() % 26 + 'A';
  }
  chaine[taille] = '\0';
  return chaine;
}


x86 assembly (clang, -O0):
<alea_chaine>:
push   %rbp
mov    %rsp,%rbp
sub    $0x10,%rsp
mov    %rdi,-0x8(%rbp)
mov    %esi,-0xc(%rbp)
movl   $0x0,-0x10(%rbp)
mov    -0x10(%rbp),%eax
cmp    -0xc(%rbp),%eax
jge    115d <alea_chaine+0x4d>
mov    $0x0,%al
call   1030 <rand@plt>
mov    $0x1a,%ecx
cltd
idiv   %ecx
add    $0x41,%edx
mov    -0x8(%rbp),%rax
movslq -0x10(%rbp),%rcx
mov    %dl,(%rax,%rcx,1)
mov    -0x10(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x10(%rbp)
jmp    1126 <alea_chaine+0x16>
mov    -0x8(%rbp),%rax
movslq -0xc(%rbp),%rcx
movb   $0x0,(%rax,%rcx,1)
mov    -0x8(%rbp),%rax
add    $0x10,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<alea_chaine>:
push   %rbp
push   %r15
push   %r14
push   %rbx
push   %rax
mov    %esi,%r14d
mov    %rdi,%r15
test   %esi,%esi
jle    1166 <alea_chaine+0x56>
mov    %r14d,%ebp
xor    %ebx,%ebx
cs nopw 0x0(%rax,%rax,1)
xor    %eax,%eax
call   1030 <rand@plt>
cltq
imul   $0x4ec4ec4f,%rax,%rcx
mov    %rcx,%rdx
shr    $0x3f,%rdx
sar    $0x23,%rcx
add    %edx,%ecx
lea    (%rcx,%rcx,4),%edx
lea    (%rdx,%rdx,4),%edx
add    %ecx,%edx
sub    %edx,%eax
add    $0x41,%al
mov    %al,(%r15,%rbx,1)
add    $0x1,%rbx
cmp    %rbx,%rbp
jne    1130 <alea_chaine+0x20>
movslq %r14d,%rax
movb   $0x0,(%r15,%rax,1)
mov    %r15,%rax
add    $0x8,%rsp
pop    %rbx
pop    %r14
pop    %r15
pop    %rbp
ret

LLVM IR (-O0):
define i8* @alea_chaine(i8* %0, i32 %1) {
%3 = alloca i8*
%4 = alloca i32
%5 = alloca i32
store i8* %0, i8** %3
store i32 %1, i32* %4
store i32 0, i32* %5
br label %6
6: ; preds = %19, %2
%7 = load i32, i32* %5
%8 = load i32, i32* %4
%9 = icmp slt i32 %7, %8
br i1 %9, label %10, label %22
10: ; preds = %6
%11 = call i32 (...) @rand()
%12 = srem i32 %11, 26
%13 = add nsw i32 %12, 65
%14 = trunc i32 %13 to i8
%15 = load i8*, i8** %3
%16 = load i32, i32* %5
%17 = sext i32 %16 to i64
%18 = getelementptr inbounds i8, i8* %15, i64 %17
store i8 %14, i8* %18
br label %19
19: ; preds = %10
%20 = load i32, i32* %5
%21 = add nsw i32 %20, 1
store i32 %21, i32* %5
br label %6
22: ; preds = %6
%23 = load i8*, i8** %3
%24 = load i32, i32* %4
%25 = sext i32 %24 to i64
%26 = getelementptr inbounds i8, i8* %23, i64 %25
store i8 0, i8* %26
%27 = load i8*, i8** %3
ret i8* %27
}

LLVM IR (-O2):
define i8* @alea_chaine(i8* returned writeonly %0, i32 %1) {
%3 = icmp sgt i32 %1, 0
br i1 %3, label %4, label %15
4: ; preds = %2
%5 = zext i32 %1 to i64
br label %6
6: ; preds = %4, %6
%7 = phi i64 [ 0, %4 ], [ %13, %6 ]
%8 = tail call i32 (...) @rand()
%9 = srem i32 %8, 26
%10 = trunc i32 %9 to i8
%11 = add nsw i8 %10, 65
%12 = getelementptr inbounds i8, i8* %0, i64 %7
store i8 %11, i8* %12
%13 = add nuw nsw i64 %7, 1
%14 = icmp eq i64 %13, %5
br i1 %14, label %15, label %6
15: ; preds = %6, %2
%16 = sext i32 %1 to i64
%17 = getelementptr inbounds i8, i8* %0, i64 %16
store i8 0, i8* %17
ret i8* %0
}