Improve dead code elimination by transitively marking live code and removing all dead code. Replace…

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index fc57aa879c68111e4158f7db07ebe685c2790110..728cbdf956b7a6ca8969e489d25334f3740323bf 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -648,7 +648,6 @@ void HValue::SetOperandAt(int index, HValue* value) {
 void HValue::DeleteAndReplaceWith(HValue* other) {
   // We replace all uses first, so Delete can assert that there are none.
   if (other != NULL) ReplaceAllUsesWith(other);
-  ASSERT(HasNoUses());
   Kill();
   DeleteFromGraph();
 }
@@ -1899,7 +1898,6 @@ void HPhi::PrintTo(StringStream* stream) {
               double_non_phi_uses() + double_indirect_uses(),
               tagged_non_phi_uses() + tagged_indirect_uses());
   stream->Add("%s%s]",

[Sven Panne, 2013/05/07 13:32:10]

Do we never print phis marked as dead by DCE? If this is the case, removing this
piece information is OK here (at least if you adapt the format pattern ;-). If
not, print it.

[titzer, 2013/05/13 13:29:38]

Done.

-              is_live() ? "_live" : "",
               IsConvertibleToInteger() ? "" : "_ncti");
 }