Speculative execution and malloc

Question

After reading about Spectre & Meltdown vulnerabilities, I learned about speculative execution.

Given the following simple C++ program:

#include <stdlib.h>

void mallocBranch(int i) {
   if (i < 500) {
      malloc(i);
   }
}

int main(int argc, char** argv){
   for (i := 0; i < 5000; i++) {
      mallocBranch(1);
   }
   mallocBranch(500000000);

   return 0;
}

• I am assuming that the malloc calls are not optimized out by the compiler.

Q: What happens when mallocBranch(500000000) is called? Will the CPU look at the branch-prediction cache and see that past calls to if (i < 500) succeeded and speculatively execute the branch with malloc(500000000)? Would the number of branches in malloc overwrite the entire contents of the branch-prediction cache each time? If malloc(500000000) is actually speculatively executed, would 500million bytes of memory be allocated to the process, if only temporarily?