Merged r12362 into 3.12 branch.

src/arm/lithium-codegen-arm.cc

Index: src/arm/lithium-codegen-arm.cc
diff --git a/src/arm/lithium-codegen-arm.cc b/src/arm/lithium-codegen-arm.cc
index cf9dcd30fa4bed71ee837f0a0e34ad0985a6c4d4..57735c885f5f0d7c481ef70f6a7d6ce3d0c2db16 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -3833,7 +3833,28 @@ void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* instr) {
 }
 
 
+void LCodeGen::DeoptIfTaggedButNotSmi(LEnvironment* environment,
+                                      HValue* value,
+                                      LOperand* operand) {
+  if (value->representation().IsTagged() && !value->type().IsSmi()) {
+    if (operand->IsRegister()) {
+      __ tst(ToRegister(operand), Operand(kSmiTagMask));
+    } else {
+      __ mov(ip, ToOperand(operand));
+      __ tst(ip, Operand(kSmiTagMask));
+    }
+    DeoptimizeIf(ne, environment);
+  }
+}
+
+
 void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
+  DeoptIfTaggedButNotSmi(instr->environment(),
+                         instr->hydrogen()->length(),
+                         instr->length());
+  DeoptIfTaggedButNotSmi(instr->environment(),
+                         instr->hydrogen()->index(),
+                         instr->index());
   if (instr->index()->IsConstantOperand()) {
     int constant_index =
         ToInteger32(LConstantOperand::cast(instr->index()));