Eliminate map checks of constant values.

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 2cec68b097573eab83f941c03940b01647f2e3e9..5bd5dc70fabb9063b612c674ff9e2bff64430d07 100644
--- a/src/x64/lithium-x64.cc
+++ b/src/x64/lithium-x64.cc
@@ -1949,8 +1949,10 @@ LInstruction* LChunkBuilder::DoCheckInstanceType(HCheckInstanceType* instr) {
 
 
 LInstruction* LChunkBuilder::DoCheckPrototypeMaps(HCheckPrototypeMaps* instr) {
-  LUnallocated* temp = TempRegister();
+  LUnallocated* temp = NULL;
+  if (!instr->CanOmitPrototypeChecks()) temp = TempRegister();
   LCheckPrototypeMaps* result = new(zone()) LCheckPrototypeMaps(temp);
+  if (instr->CanOmitPrototypeChecks()) return result;
   return AssignEnvironment(result);
 }
 
@@ -1962,8 +1964,10 @@ LInstruction* LChunkBuilder::DoCheckFunction(HCheckFunction* instr) {
 
 
 LInstruction* LChunkBuilder::DoCheckMaps(HCheckMaps* instr) {
-  LOperand* value = UseRegisterAtStart(instr->value());
+  LOperand* value = NULL;
+  if (!instr->CanOmitMapChecks()) value = UseRegisterAtStart(instr->value());
   LCheckMaps* result = new(zone()) LCheckMaps(value);
+  if (instr->CanOmitMapChecks()) return result;
   return AssignEnvironment(result);
 }