[PATCH] [2/2] Add PRFCHW feature to a few AMD processors

[Craig Topper]

  I think based on gcc behavior,

  def HasPrefetchW : Predicate<"Subtarget->has3DNow() || Subtarget->hasPRFCHW()">;

  should only be just Subtarget->hasPRFCHW()


  Then in clang, towards the end of HandleTargetFeatures. Force a +prftchw into the features if 3dnow is enabled and -prftchw was not specified on the command line. Similar to the coupling of sse4.2 and popcnt down there. This allows prfchw to be disabled independent of 3dnow.

http://llvm-reviews.chandlerc.com/D1934