Infrastructure classes for evaluating numeric relations between values.

src/hydrogen-instructions.cc

Index: src/hydrogen-instructions.cc
diff --git a/src/hydrogen-instructions.cc b/src/hydrogen-instructions.cc
index 11cc901b38ccfccf7a3607f99e1088b47b7f4ac9..6b7a08f8e87de43440b64ea830072964af42f37d 100644
--- a/src/hydrogen-instructions.cc
+++ b/src/hydrogen-instructions.cc
@@ -524,6 +524,17 @@ const char* HValue::Mnemonic() const {
 }
 
 
+bool HValue::IsInteger32Constant() {
+  return IsConstant() && HConstant::cast(this)->HasInteger32Value();
+}
+
+
+int32_t HValue::GetInteger32Constant() {
+  ASSERT(IsInteger32Constant());
+  return HConstant::cast(this)->Integer32Value();
+}
+
+
 void HValue::SetOperandAt(int index, HValue* value) {
   RegisterUse(index, value);
   InternalSetOperandAt(index, value);
@@ -690,6 +701,14 @@ void HInstruction::PrintMnemonicTo(StringStream* stream) {
 }
 
 
+HValue* HValue::AddNumericConstraint(HInstruction* insertion_point,
+                                     HValue* related_value,
+                                     NumericRelation relation) {
+  return HNumericConstraint::New(
+      insertion_point, this, related_value, relation);
+}
+
+
 void HInstruction::Unlink() {
   ASSERT(IsLinked());
   ASSERT(!IsControlInstruction());  // Must never move control instructions.
@@ -794,6 +813,27 @@ void HInstruction::Verify() {
 #endif
 
 
+HNumericConstraint* HNumericConstraint::New(HInstruction* insertion_point,
+                                            HValue* constrained_value,
+                                            HValue* related_value,
+                                            NumericRelation relation) {
+  HNumericConstraint* result =
+      new(insertion_point->block()->zone()) HNumericConstraint(
+          constrained_value, related_value, relation);
+  result->InsertAfter(insertion_point);
+  return result;
+}
+
+
+void HNumericConstraint::PrintDataTo(StringStream* stream) {
+  stream->Add("(");
+  constrained_value()->PrintNameTo(stream);
+  stream->Add(" %s ", relation().Mnemonic());
+  related_value()->PrintNameTo(stream);
+  stream->Add(")");
+}
+
+
 void HDummyUse::PrintDataTo(StringStream* stream) {
   value()->PrintNameTo(stream);
 }
@@ -815,6 +855,18 @@ void HBinaryCall::PrintDataTo(StringStream* stream) {
 }
 
 
+bool HBoundsCheck::CheckRelation(NumericRelation relation,
+                                         HValue* related_value) {
+  if (related_value == length()) {
+    return NumericRelation::Lt().Implies(relation);
+  } else if (related_value == block()->graph()->GetConstant0()) {
+    return NumericRelation::Ge().Implies(relation);
+  } else {
+    return false;
+  }
+}
+
+
 void HBoundsCheck::PrintDataTo(StringStream* stream) {
   index()->PrintNameTo(stream);
   stream->Add(" ");
@@ -1476,6 +1528,31 @@ Range* HMod::InferRange(Zone* zone) {
 }
 
 
+void HPhi::AddInformativeDefinitions() {
+  HValue* induction_base = NULL;
+  NumericRelation relation = NumericRelation::None();
+  if (OperandCount() == 2) {
+    if (OperandAt(0)->IsRelationTrue(NumericRelation::Ge(), this)) {
+      induction_base = OperandAt(1);
+      relation = NumericRelation::Ge();
+    } else if (OperandAt(0)->IsRelationTrue(NumericRelation::Le(), this)) {
+      induction_base = OperandAt(1);
+      relation = NumericRelation::Ge();
+    } else if (OperandAt(1)->IsRelationTrue(NumericRelation::Ge(), this)) {
+      induction_base = OperandAt(0);
+      relation = NumericRelation::Ge();
+    } else if (OperandAt(1)->IsRelationTrue(NumericRelation::Le(), this)) {
+      induction_base = OperandAt(0);
+      relation = NumericRelation::Ge();
+    }
+  }
+
+  if (induction_base == NULL) return;
+
+  AddNumericConstraint(block()->first(), induction_base, relation);
+}
+
+
 Range* HMathMinMax::InferRange(Zone* zone) {
   if (representation().IsInteger32()) {
     Range* a = left()->range();
@@ -1937,6 +2014,15 @@ void HStringCompareAndBranch::PrintDataTo(StringStream* stream) {
 }
 
 
+void HCompareIDAndBranch::AddInformativeDefinitions() {
+  NumericRelation r = NumericRelation::FromToken(token());
+  if (r == NumericRelation::None()) return;
+
+  left()->AddNumericConstraint(SuccessorAt(0)->first(), right(), r);
+  left()->AddNumericConstraint(SuccessorAt(1)->first(), right(), r.Reversed());
+}
+
+
 void HCompareIDAndBranch::PrintDataTo(StringStream* stream) {
   stream->Add(Token::Name(token()));
   stream->Add(" ");