Hello,
have a short look at the following simple c-prog:
#include <stdlib.h>
int main(int argc, char* argv) {
void* buf = malloc(10 * sizeof(char*));
/* do sth with buf, so that it is not “optimized away” */
return 0;
}
When you compile this using a plain llvm-gcc, the call to libc-malloc is left inside.But compiling it with -O2 alters the call to llvm::MallocInst.
Now i would like to know, why this is done.
Is the libc-malloc still used?
There is also a pass, called RaiseAllocation (well … at least i think so) and i remember in previous versions (2.2)
of llvm i read a commentary inside the sourcecode that the pass should be used with care because
llvm::MallocInst is not platform-independent. This commentary is removed in the current version. - Why?
This is nothing serious - i am just curious to know some more details 
Thank you in advance.