Generalize bounds checks.

runtime/vm/intermediate_language_x64.cc

Index: runtime/vm/intermediate_language_x64.cc
diff --git a/runtime/vm/intermediate_language_x64.cc b/runtime/vm/intermediate_language_x64.cc
index c497bd487821120985f0aa70e5e322de70682783..b8865ec2d5723b1d2291020c43618d33542a5ade 100644
--- a/runtime/vm/intermediate_language_x64.cc
+++ b/runtime/vm/intermediate_language_x64.cc
@@ -5287,10 +5287,10 @@ LocationSummary* CheckClassInstr::MakeLocationSummary(Isolate* isolate,
 
 
 void CheckClassInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  const ICData::DeoptReasonId deopt_reason = licm_hoisted_ ?
-      ICData::kDeoptHoistedCheckClass : ICData::kDeoptCheckClass;
+  Label* deopt = compiler->AddDeoptStub(deopt_id(),
+                                        ICData::kDeoptCheckClass,
+                                        licm_hoisted_ ? ICData::kHoisted : 0);
   if (IsNullCheck()) {
-    Label* deopt = compiler->AddDeoptStub(deopt_id(), deopt_reason);
     __ CompareObject(locs()->in(0).reg(),
                      Object::null_object(), PP);
     __ j(EQUAL, deopt);
@@ -5301,7 +5301,6 @@ void CheckClassInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
          (unary_checks().NumberOfChecks() > 1));
   Register value = locs()->in(0).reg();
   Register temp = locs()->temp(0).reg();
-  Label* deopt = compiler->AddDeoptStub(deopt_id(), deopt_reason);
   Label is_ok;
   intptr_t cix = 0;
   if (unary_checks().GetReceiverClassIdAt(cix) == kSmiCid) {
@@ -5401,8 +5400,10 @@ LocationSummary* CheckArrayBoundInstr::MakeLocationSummary(Isolate* isolate,
 
 
 void CheckArrayBoundInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
-  Label* deopt = compiler->AddDeoptStub(deopt_id(),
-                                        ICData::kDeoptCheckArrayBound);
+  Label* deopt = compiler->AddDeoptStub(
+      deopt_id(),
+      ICData::kDeoptCheckArrayBound,
+      generalized_ ? ICData::kGeneralized : 0);
 
   Location length_loc = locs()->in(kLengthPos);
   Location index_loc = locs()->in(kIndexPos);
@@ -5426,9 +5427,14 @@ void CheckArrayBoundInstr::EmitNativeCode(FlowGraphCompiler* compiler) {
   } else if (length_loc.IsConstant()) {
     const Smi& length = Smi::Cast(length_loc.constant());
     Register index = index_loc.reg();
-    __ CompareImmediate(
-        index, Immediate(reinterpret_cast<int64_t>(length.raw())), PP);
-    __ j(ABOVE_EQUAL, deopt);
+    if (length.Value() == Smi::kMaxValue) {
+      __ testq(index, index);
+      __ j(NEGATIVE, deopt);
+    } else {
+      __ CompareImmediate(
+          index, Immediate(reinterpret_cast<int64_t>(length.raw())), PP);
+      __ j(ABOVE_EQUAL, deopt);
+    }
   } else {
     Register length = length_loc.reg();
     Register index = index_loc.reg();