Don't emit code for instructions that are hiding behind an HSoftDeoptimize

src/x64/lithium-x64.cc

Index: src/x64/lithium-x64.cc
diff --git a/src/x64/lithium-x64.cc b/src/x64/lithium-x64.cc
index c9c99de1254fa12909cf2b234ef15345e307708c..f52eff7db52af1d5565b7ce1ba1a5a6db6faafa6 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -686,6 +686,11 @@ LInstruction* LChunkBuilder::DoBlockEntry(HBlockEntry* instr) {
 }
 
 
+LInstruction* LChunkBuilder::DoDummyUse(HDummyUse* instr) {
+  return DefineAsRegister(new(zone()) LDummyUse(UseAny(instr->value())));
+}
+
+
 LInstruction* LChunkBuilder::DoSoftDeoptimize(HSoftDeoptimize* instr) {
   return AssignEnvironment(new(zone()) LDeoptimize);
 }