Eliminate redundant smi checks

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 5bf5b48c22e4ee57fe50f9bc10948e043ac14b6e..993bf1f60406f0b4e742d002b6a830fa14a8f569 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -1712,22 +1712,22 @@ void HLoadKeyedFastElement::PrintDataTo(StringStream* stream) {
   stream->Add("[");
   key()->PrintNameTo(stream);
   stream->Add("]");
-  if (hole_check_mode_ == PERFORM_HOLE_CHECK) {
+  if (IsFastHoleyElementsKind(elements_kind())) {

[Michael Starzinger, 2012/06/12 08:10:43]

It seems as if we don't need the hole_check_mode flag for this instruction
anymore, because it solely depends on the elements kind. Can we get rid of the
flag, move the IsFastHoleyElementsKind() into a
HLoadKeyedFastElements::MightHaveHoles() helper method and use this helper
method here?

[danno, 2012/06/12 09:59:22]

Done.

     stream->Add(" check_hole");
   }
 }
 
 
 bool HLoadKeyedFastElement::RequiresHoleCheck() {
-  if (hole_check_mode_ == OMIT_HOLE_CHECK) {
+  if (IsFastPackedElementsKind(elements_kind())) {

[Michael Starzinger, 2012/06/12 08:10:43]

Likewise.

[danno, 2012/06/12 09:59:22]

The hole check value is gone, but we still need to answer the question by
implementing this function, so this code still seems necessary.
On 2012/06/12 08:10:43, Michael Starzinger wrote:

     return false;
   }
-
+  
   for (HUseIterator it(uses()); !it.Done(); it.Advance()) {
     HValue* use = it.value();
     if (!use->IsChange()) return true;
   }
-
+  
   return false;
 }