MEMORY_LEAK false alarm

Why does `infer run --pulse -- clang -c test.c` report MEMORY_LEAK for the following code?

```
//test.c
int foo(int a, int b){
char *p = NULL;
if(a > b){
p = malloc(100);
}

if(a > b){
free(p);
}
return 0;
}
```