Add Uint32AddWithOverflow and Uint32SubWithOverflow machine operators.

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

 // Copyright 2014 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/compiler/instruction-selector-impl.h"
 #include "src/compiler/node-matchers.h"
 #include "src/compiler-intrinsics.h"
 
 namespace v8 {
 namespace internal {
@@ skipping 286 matching lines @@
 }
 
 
 static void VisitBinop(InstructionSelector* selector, Node* node,
                        InstructionCode opcode, InstructionCode reverse_opcode) {
   FlagsContinuation cont;
   VisitBinop(selector, node, opcode, reverse_opcode, &cont);
 }
 
 
+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);
   Node* base = node->InputAt(0);
   Node* index = node->InputAt(1);
 
   InstructionOperand* result = rep == kMachineFloat64
                                    ? g.DefineAsDoubleRegister(node)
                                    : g.DefineAsRegister(node);
 
@@ skipping 246 matching lines @@
   if (m.right().IsInt32Mul() && CanCover(node, m.right().node())) {
     Int32BinopMatcher mright(m.right().node());
     Emit(kArmMla, g.DefineAsRegister(node), g.UseRegister(mright.left().node()),
          g.UseRegister(mright.right().node()), g.UseRegister(m.left().node()));
     return;
   }
   VisitBinop(this, node, kArmAdd, kArmAdd);
 }
 
 
+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);
   if (IsSupported(MLS) && m.right().IsInt32Mul() &&
       CanCover(node, m.right().node())) {
     Int32BinopMatcher mright(m.right().node());
     Emit(kArmMls, g.DefineAsRegister(node), g.UseRegister(mright.left().node()),
          g.UseRegister(mright.right().node()), g.UseRegister(m.left().node()));
     return;
   }
   VisitBinop(this, node, kArmSub, kArmRsb);
 }
 
 
+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);
   if (m.right().HasValue() && m.right().Value() > 0) {
     int32_t value = m.right().Value();
     if (IsPowerOf2(value - 1)) {
       Emit(kArmAdd | AddressingModeField::encode(kMode_Operand2_R_LSL_I),
            g.DefineAsRegister(node), g.UseRegister(m.left().node()),
            g.UseRegister(m.left().node()),
            g.TempImmediate(WhichPowerOf2(value - 1)));
@@ skipping 167 matching lines @@
 
 
 void InstructionSelector::VisitFloat64Mod(Node* node) {
   ArmOperandGenerator g(this);
   Emit(kArmVmodF64, g.DefineAsFixedDouble(node, d0),
        g.UseFixedDouble(node->InputAt(0), d0),
        g.UseFixedDouble(node->InputAt(1), d1))->MarkAsCall();
 }
 
 
+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);
   CallDescriptor* descriptor = OpParameter<CallDescriptor*>(call);
   CallBuffer buffer(zone(), descriptor);  // TODO(turbofan): temp zone here?
 
   // Compute InstructionOperands for inputs and outputs.
   // TODO(turbofan): on ARM64 it's probably better to use the code object in a
   // register if there are multiple uses of it. Improve constant pool and the
   // heuristics in the register allocator for where to emit constants.
@@ skipping 39 matching lines @@
 
   // Caller clean up of stack for C-style calls.
   if (descriptor->kind() == CallDescriptor::kCallAddress &&
       buffer.pushed_count > 0) {
     DCHECK(deoptimization == NULL && continuation == NULL);
     Emit(kArmDrop | MiscField::encode(buffer.pushed_count), NULL);
   }
 }
 
 
-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,
                              bool commutative) {
   ArmOperandGenerator g(selector);
   Int32BinopMatcher m(node);
   InstructionOperand* inputs[5];
   size_t input_count = 0;
   InstructionOperand* outputs[1];
   size_t output_count = 0;
@@ skipping 79 matching lines @@
     DCHECK(cont->IsSet());
     Emit(cont->Encode(kArmVcmpF64), g.DefineAsRegister(cont->result()),
          g.UseDoubleRegister(m.left().node()),
          g.UseDoubleRegister(m.right().node()));
   }
 }
 
 }  // namespace compiler
 }  // namespace internal
 }  // namespace v8