Improve code generation for bounds checks.

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 0c3e5795391145d69106a18ed9485a9705df31e8..ee695e4f6d47893f9a677533ad137ba8a01b9784 100644
--- a/src/arm/lithium-codegen-arm.cc
+++ b/src/arm/lithium-codegen-arm.cc
@@ -4188,35 +4188,26 @@ void LCodeGen::DoStoreNamedGeneric(LStoreNamedGeneric* instr) {
 }
 
 
-void LCodeGen::ApplyCheckIf(Condition condition, LBoundsCheck* check) {
-  if (FLAG_debug_code && check->hydrogen()->skip_check()) {
+void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
+  Condition cc = instr->hydrogen()->allow_equality() ? hi : hs;
+  if (instr->index()->IsConstantOperand()) {
+    Operand index = ToOperand(instr->index());
+    Register length = ToRegister(instr->length());
+    __ cmp(length, index);
+    cc = ReverseCondition(cc);
+  } else {
+    Register index = ToRegister(instr->index());
+    Operand length = ToOperand(instr->length());
+    __ cmp(index, length);
+  }
+  if (FLAG_debug_code && instr->hydrogen()->skip_check()) {
     Label done;
-    __ b(NegateCondition(condition), &done);
+    __ b(NegateCondition(cc), &done);
     __ stop("eliminated bounds check failed");
     __ bind(&done);
   } else {
-    DeoptimizeIf(condition, check->environment());
-  }
-}
-
-
-void LCodeGen::DoBoundsCheck(LBoundsCheck* instr) {
-  if (instr->hydrogen()->skip_check()) return;
-
-  if (instr->index()->IsConstantOperand()) {
-    int constant_index =
-        ToInteger32(LConstantOperand::cast(instr->index()));
-    if (instr->hydrogen()->length()->representation().IsSmi()) {
-      __ mov(ip, Operand(Smi::FromInt(constant_index)));
-    } else {
-      __ mov(ip, Operand(constant_index));
-    }
-    __ cmp(ip, ToRegister(instr->length()));
-  } else {
-    __ cmp(ToRegister(instr->index()), ToRegister(instr->length()));
+    DeoptimizeIf(cc, instr->environment());
   }
-  Condition condition = instr->hydrogen()->allow_equality() ? hi : hs;
-  ApplyCheckIf(condition, instr);
 }