Add Uint32AddWithOverflow and Uint32SubWithOverflow machine operators.

src/compiler/arm/instruction-selector-arm.cc

Index: src/compiler/arm/instruction-selector-arm.cc
diff --git a/src/compiler/arm/instruction-selector-arm.cc b/src/compiler/arm/instruction-selector-arm.cc
index 9e2f79a4a6dc320d05c08d69ea36f9dc3f0d37d4..42720a0578c23d8dc46c22b1b7d56fcaa9eeb300 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -304,6 +304,18 @@ static void VisitBinop(InstructionSelector* selector, Node* node,
 }
 
 
+static void VisitBinop(InstructionSelector* selector, Node* node,
+                       InstructionCode opcode, InstructionCode reverse_opcode,
+                       FlagsCondition overflow_condition) {
+  if (Node* overflow = node->FindProjection(1)) {
+    FlagsContinuation cont(overflow_condition, overflow);
+    return VisitBinop(selector, node, opcode, reverse_opcode, &cont);
+  }
+  FlagsContinuation cont;
+  return VisitBinop(selector, node, opcode, reverse_opcode, &cont);
+}
+
+
 void InstructionSelector::VisitLoad(Node* node) {
   MachineRepresentation rep = OpParameter<MachineRepresentation>(node);
   ArmOperandGenerator g(this);
@@ -570,6 +582,16 @@ void InstructionSelector::VisitInt32Add(Node* node) {
 }
 
 
+void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
+  VisitBinop(this, node, kArmAdd, kArmAdd, kOverflow);
+}
+
+
+void InstructionSelector::VisitUint32AddWithOverflow(Node* node) {
+  VisitBinop(this, node, kArmAdd, kArmAdd, kUnsignedGreaterThanOrEqual);
+}
+
+
 void InstructionSelector::VisitInt32Sub(Node* node) {
   ArmOperandGenerator g(this);
   Int32BinopMatcher m(node);
@@ -584,6 +606,16 @@ void InstructionSelector::VisitInt32Sub(Node* node) {
 }
 
 
+void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
+  VisitBinop(this, node, kArmSub, kArmRsb, kOverflow);
+}
+
+
+void InstructionSelector::VisitUint32SubWithOverflow(Node* node) {
+  VisitBinop(this, node, kArmSub, kArmRsb, kUnsignedLessThan);
+}
+
+
 void InstructionSelector::VisitInt32Mul(Node* node) {
   ArmOperandGenerator g(this);
   Int32BinopMatcher m(node);
@@ -771,6 +803,104 @@ void InstructionSelector::VisitFloat64Mod(Node* node) {
 }
 
 
+void InstructionSelector::VisitBranch(Node* branch, BasicBlock* tbranch,
+                                      BasicBlock* fbranch) {
+  OperandGenerator g(this);
+  Node* user = branch;
+  Node* value = branch->InputAt(0);
+
+  FlagsContinuation cont(kNotEqual, tbranch, fbranch);
+
+  // If we can fall through to the true block, invert the branch.
+  if (IsNextInAssemblyOrder(tbranch)) {
+    cont.Negate();
+    cont.SwapBlocks();
+  }
+
+  // Try to combine with comparisons against 0 by simply inverting the branch.
+  while (CanCover(user, value)) {
+    if (value->opcode() == IrOpcode::kWord32Equal) {
+      Int32BinopMatcher m(value);
+      if (m.right().Is(0)) {
+        user = value;
+        value = m.left().node();
+        cont.Negate();
+      } else {
+        break;
+      }
+    } else {
+      break;
+    }
+  }
+
+  // Try to combine the branch with a comparison.
+  if (CanCover(user, value)) {
+    switch (value->opcode()) {
+      case IrOpcode::kWord32Equal:
+        cont.OverwriteAndNegateIfEqual(kEqual);
+        return VisitWord32Compare(value, &cont);
+      case IrOpcode::kInt32LessThan:
+        cont.OverwriteAndNegateIfEqual(kSignedLessThan);
+        return VisitWord32Compare(value, &cont);
+      case IrOpcode::kInt32LessThanOrEqual:
+        cont.OverwriteAndNegateIfEqual(kSignedLessThanOrEqual);
+        return VisitWord32Compare(value, &cont);
+      case IrOpcode::kUint32LessThan:
+        cont.OverwriteAndNegateIfEqual(kUnsignedLessThan);
+        return VisitWord32Compare(value, &cont);
+      case IrOpcode::kUint32LessThanOrEqual:
+        cont.OverwriteAndNegateIfEqual(kUnsignedLessThanOrEqual);
+        return VisitWord32Compare(value, &cont);
+      case IrOpcode::kFloat64Equal:
+        cont.OverwriteAndNegateIfEqual(kUnorderedEqual);
+        return VisitFloat64Compare(value, &cont);
+      case IrOpcode::kFloat64LessThan:
+        cont.OverwriteAndNegateIfEqual(kUnorderedLessThan);
+        return VisitFloat64Compare(value, &cont);
+      case IrOpcode::kFloat64LessThanOrEqual:
+        cont.OverwriteAndNegateIfEqual(kUnorderedLessThanOrEqual);
+        return VisitFloat64Compare(value, &cont);
+      case IrOpcode::kProjection:
+        // Check if this is the overflow output projection of an
+        // <Operation>WithOverflow node.
+        if (OpParameter<int32_t>(value) == 1) {
+          // We cannot combine the <Operation>WithOverflow with this branch
+          // unless the 0th projection (the use of the actual value of the
+          // <Operation> is either NULL, which means there's no use of the
+          // actual value, or was already defined, which means it is scheduled
+          // *AFTER* this branch).
+          Node* node = value->InputAt(0);
+          Node* result = node->FindProjection(0);
+          if (result == NULL || IsDefined(result)) {
+            switch (node->opcode()) {
+              case IrOpcode::kInt32AddWithOverflow:
+                cont.OverwriteAndNegateIfEqual(kOverflow);
+                return VisitBinop(this, node, kArmAdd, kArmAdd, &cont);
+              case IrOpcode::kUint32AddWithOverflow:
+                cont.OverwriteAndNegateIfEqual(kUnsignedGreaterThanOrEqual);
+                return VisitBinop(this, node, kArmAdd, kArmAdd, &cont);
+              case IrOpcode::kInt32SubWithOverflow:
+                cont.OverwriteAndNegateIfEqual(kOverflow);
+                return VisitBinop(this, node, kArmSub, kArmRsb, &cont);
+              case IrOpcode::kUint32SubWithOverflow:
+                cont.OverwriteAndNegateIfEqual(kUnsignedLessThan);
+                return VisitBinop(this, node, kArmSub, kArmRsb, &cont);
+              default:
+                break;
+            }
+          }
+        }
+        break;
+      default:
+        break;
+    }
+  }
+
+  // Branch could not be combined with a compare, emit compare against 0.
+  VisitWord32Test(value, &cont);
+}
+
+
 void InstructionSelector::VisitCall(Node* call, BasicBlock* continuation,
                                     BasicBlock* deoptimization) {
   ArmOperandGenerator g(this);
@@ -830,18 +960,6 @@ void InstructionSelector::VisitCall(Node* call, BasicBlock* continuation,
 }
 
 
-void InstructionSelector::VisitInt32AddWithOverflow(Node* node,
-                                                    FlagsContinuation* cont) {
-  VisitBinop(this, node, kArmAdd, kArmAdd, cont);
-}
-
-
-void InstructionSelector::VisitInt32SubWithOverflow(Node* node,
-                                                    FlagsContinuation* cont) {
-  VisitBinop(this, node, kArmSub, kArmRsb, cont);
-}
-
-
 // Shared routine for multiple compare operations.
 static void VisitWordCompare(InstructionSelector* selector, Node* node,
                              InstructionCode opcode, FlagsContinuation* cont,