[llvm-commits] [patch] call libc memcpy/memset for big arrays

[Rafael Espindola]

Currently we expand a memcpy/memset node to a call to the libc implementation if

  if ((Align & 3) != 0 ||
      (I && I->getValue() < Subtarget->getMinRepStrSizeThreshold())) {

Shouldn't this be a ">". The libc memcpy/memset are very fast for big arrays.

If I compile

---------------------------------------
#include <string.h>
void f1(long *a, long *b) {
  memcpy(a, b, 8 * 16);
}

void f2(long *a, long *b) {
  memcpy(a, b, 8 * 32);
}
---------------------------------------

with gcc 4.2 (-O2), it will call memcpy for f2 and not for f1.

Cheers,
-- 
Rafael Avila de Espindola

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