Improve code generation for bounds checks.

src/arm/lithium-codegen-arm.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 4170 matching lines @@
   ASSERT(ToRegister(instr->object()).is(r1));
   ASSERT(ToRegister(instr->value()).is(r0));
 
   // Name is always in r2.
   __ mov(r2, Operand(instr->name()));
   Handle<Code> ic = StoreIC::initialize_stub(isolate(), instr->strict_mode());
   CallCode(ic, RelocInfo::CODE_TARGET, instr, NEVER_INLINE_TARGET_ADDRESS);
 }
 
 
-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());
+    DeoptimizeIf(cc, instr->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()));
-  }
-  Condition condition = instr->hydrogen()->allow_equality() ? hi : hs;
-  ApplyCheckIf(condition, instr);
-}
-
-
 void LCodeGen::DoStoreKeyedExternalArray(LStoreKeyed* instr) {
   Register external_pointer = ToRegister(instr->elements());
   Register key = no_reg;
   ElementsKind elements_kind = instr->elements_kind();
   bool key_is_constant = instr->key()->IsConstantOperand();
   int constant_key = 0;
   if (key_is_constant) {
     constant_key = ToInteger32(LConstantOperand::cast(instr->key()));
     if (constant_key & 0xF0000000) {
       Abort(kArrayIndexConstantValueTooBig);
@@ skipping 1631 matching lines @@
   __ ldr(result, FieldMemOperand(scratch,
                                  FixedArray::kHeaderSize - kPointerSize));
   __ bind(deferred->exit());
   __ bind(&done);
 }
 
 
 #undef __
 
 } }  // namespace v8::internal