#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*/ isdigit(int);
scalar_t__ strlen(char *);
int is_a_number(char *what) {
  int i;
  for (i = 0; i < (int)strlen(what); i++) {
    if (!isdigit((int)what[i]))
      return 0;
  }
  return 1;
}


x86 assembly (clang, -O0):
<is_a_number>:
push   %rbp
mov    %rsp,%rbp
sub    $0x20,%rsp
mov    %rdi,-0x10(%rbp)
movl   $0x0,-0x14(%rbp)
mov    -0x14(%rbp),%eax
mov    %eax,-0x18(%rbp)
mov    -0x10(%rbp),%rdi
call   1040 <strlen@plt>
mov    %rax,%rcx
mov    -0x18(%rbp),%eax
cmp    %ecx,%eax
jge    1189 <is_a_number+0x69>
mov    -0x10(%rbp),%rax
movslq -0x14(%rbp),%rcx
movsbl (%rax,%rcx,1),%edi
call   1030 <isdigit@plt>
cmp    $0x0,%eax
jne    1176 <is_a_number+0x56>
movl   $0x0,-0x4(%rbp)
jmp    1190 <is_a_number+0x70>
jmp    117b <is_a_number+0x5b>
mov    -0x14(%rbp),%eax
add    $0x1,%eax
mov    %eax,-0x14(%rbp)
jmp    1133 <is_a_number+0x13>
movl   $0x1,-0x4(%rbp)
mov    -0x4(%rbp),%eax
add    $0x20,%rsp
pop    %rbp
ret

x86 assembly (clang, -O2):
<is_a_number>:
push   %rbx
mov    %rdi,%rbx
call   1030 <strlen@plt>
mov    %rax,%rcx
mov    $0x1,%eax
test   %ecx,%ecx
jle    1145 <is_a_number+0x35>
mov    %ecx,%ecx
xor    %edx,%edx
nopl   0x0(%rax)
movsbl (%rbx,%rdx,1),%esi
add    $0xffffffd0,%esi
cmp    $0xa,%esi
jae    1147 <is_a_number+0x37>
add    $0x1,%rdx
cmp    %rdx,%rcx
jne    1130 <is_a_number+0x20>
pop    %rbx
ret
xor    %eax,%eax
pop    %rbx
ret

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

LLVM IR (-O2):
define i32 @is_a_number(i8* nocapture %0) {
%2 = tail call i64 @strlen(i8* dereferenceable(1) %0)
%3 = trunc i64 %2 to i32
%4 = icmp sgt i32 %3, 0
br i1 %4, label %5, label %17
5: ; preds = %1
%6 = and i64 %2, 4294967295
br label %9
7: ; preds = %9
%8 = icmp eq i64 %16, %6
br i1 %8, label %17, label %9
9: ; preds = %5, %7
%10 = phi i64 [ 0, %5 ], [ %16, %7 ]
%11 = getelementptr inbounds i8, i8* %0, i64 %10
%12 = load i8, i8* %11
%13 = sext i8 %12 to i32
%14 = add nsw i32 %13, -48
%15 = icmp ult i32 %14, 10
%16 = add nuw nsw i64 %10, 1
br i1 %15, label %7, label %17
17: ; preds = %9, %7, %1
%18 = phi i32 [ 1, %1 ], [ 1, %7 ], [ 0, %9 ]
ret i32 %18
}