[turbofan] Support for combining branches with <Operation>WithOverflow.

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 e3c4f9b276a0862add51125b7c25098bc15c1f75..d60eee7a671d0627acc85df79d2a1d5e836d5fb0 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -249,46 +249,12 @@ static inline bool TryMatchImmediateOrShift(InstructionSelector* selector,
 }
 
 
-// Shared routine for multiple binary operations.
 static void VisitBinop(InstructionSelector* selector, Node* node,
-                       InstructionCode opcode, InstructionCode reverse_opcode) {
-  ArmOperandGenerator g(selector);
-  Int32BinopMatcher m(node);
-  InstructionOperand* inputs[3];
-  size_t input_count = 0;
-  InstructionOperand* outputs[1] = {g.DefineAsRegister(node)};
-  const size_t output_count = ARRAY_SIZE(outputs);
-
-  if (TryMatchImmediateOrShift(selector, &opcode, m.right().node(),
-                               &input_count, &inputs[1])) {
-    inputs[0] = g.UseRegister(m.left().node());
-    input_count++;
-  } else if (TryMatchImmediateOrShift(selector, &reverse_opcode,
-                                      m.left().node(), &input_count,
-                                      &inputs[1])) {
-    inputs[0] = g.UseRegister(m.right().node());
-    opcode = reverse_opcode;
-    input_count++;
-  } else {
-    opcode |= AddressingModeField::encode(kMode_Operand2_R);
-    inputs[input_count++] = g.UseRegister(m.left().node());
-    inputs[input_count++] = g.UseRegister(m.right().node());
-  }
-
-  ASSERT_NE(0, input_count);
-  ASSERT_GE(ARRAY_SIZE(inputs), input_count);
-  ASSERT_NE(kMode_None, AddressingModeField::decode(opcode));
-
-  selector->Emit(opcode, output_count, outputs, input_count, inputs);
-}
-
-
-static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
-                                   InstructionCode opcode,
-                                   InstructionCode reverse_opcode) {
+                       InstructionCode opcode, InstructionCode reverse_opcode,
+                       FlagsContinuation* cont) {
   ArmOperandGenerator g(selector);
   Int32BinopMatcher m(node);
-  InstructionOperand* inputs[3];
+  InstructionOperand* inputs[5];
   size_t input_count = 0;
   InstructionOperand* outputs[2];
   size_t output_count = 0;
@@ -309,16 +275,14 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
     inputs[input_count++] = g.UseRegister(m.right().node());
   }
 
-  // Define outputs depending on the projections.
-  Node* projections[2];
-  node->CollectProjections(ARRAY_SIZE(projections), projections);
-  if (projections[0]) {
-    outputs[output_count++] = g.DefineAsRegister(projections[0]);
+  if (cont->IsBranch()) {
+    inputs[input_count++] = g.Label(cont->true_block());
+    inputs[input_count++] = g.Label(cont->false_block());
   }
-  if (projections[1]) {
-    opcode |= FlagsModeField::encode(kFlags_set);
-    opcode |= FlagsConditionField::encode(kOverflow);
-    outputs[output_count++] = g.DefineAsRegister(projections[1]);
+
+  outputs[output_count++] = g.DefineAsRegister(node);
+  if (cont->IsSet()) {
+    outputs[output_count++] = g.DefineAsRegister(cont->result());
   }
 
   ASSERT_NE(0, input_count);
@@ -327,7 +291,16 @@ static void VisitBinopWithOverflow(InstructionSelector* selector, Node* node,
   ASSERT_GE(ARRAY_SIZE(outputs), output_count);
   ASSERT_NE(kMode_None, AddressingModeField::decode(opcode));
 
-  selector->Emit(opcode, output_count, outputs, input_count, inputs);
+  Instruction* instr = selector->Emit(cont->Encode(opcode), output_count,
+                                      outputs, input_count, inputs);
+  if (cont->IsBranch()) instr->MarkAsControl();
+}
+
+
+static void VisitBinop(InstructionSelector* selector, Node* node,
+                       InstructionCode opcode, InstructionCode reverse_opcode) {
+  FlagsContinuation cont;
+  VisitBinop(selector, node, opcode, reverse_opcode, &cont);
 }
 
 
@@ -597,11 +570,6 @@ void InstructionSelector::VisitInt32Add(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32AddWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kArmAdd, kArmAdd);
-}
-
-
 void InstructionSelector::VisitInt32Sub(Node* node) {
   ArmOperandGenerator g(this);
   Int32BinopMatcher m(node);
@@ -616,11 +584,6 @@ void InstructionSelector::VisitInt32Sub(Node* node) {
 }
 
 
-void InstructionSelector::VisitInt32SubWithOverflow(Node* node) {
-  VisitBinopWithOverflow(this, node, kArmSub, kArmRsb);
-}
-
-
 void InstructionSelector::VisitInt32Mul(Node* node) {
   ArmOperandGenerator g(this);
   Int32BinopMatcher m(node);
@@ -867,10 +830,22 @@ 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,
-                             bool commutative, bool requires_output) {
+                             bool commutative) {
   ArmOperandGenerator g(selector);
   Int32BinopMatcher m(node);
   InstructionOperand* inputs[5];
@@ -894,9 +869,6 @@ static void VisitWordCompare(InstructionSelector* selector, Node* node,
   }
 
   if (cont->IsBranch()) {
-    if (requires_output) {
-      outputs[output_count++] = g.DefineAsRegister(node);
-    }
     inputs[input_count++] = g.Label(cont->true_block());
     inputs[input_count++] = g.Label(cont->false_block());
   } else {
@@ -917,15 +889,15 @@ static void VisitWordCompare(InstructionSelector* selector, Node* node,
 void InstructionSelector::VisitWord32Test(Node* node, FlagsContinuation* cont) {
   switch (node->opcode()) {
     case IrOpcode::kInt32Add:
-      return VisitWordCompare(this, node, kArmCmn, cont, true, false);
+      return VisitWordCompare(this, node, kArmCmn, cont, true);
     case IrOpcode::kInt32Sub:
-      return VisitWordCompare(this, node, kArmCmp, cont, false, false);
+      return VisitWordCompare(this, node, kArmCmp, cont, false);
     case IrOpcode::kWord32And:
-      return VisitWordCompare(this, node, kArmTst, cont, true, false);
+      return VisitWordCompare(this, node, kArmTst, cont, true);
     case IrOpcode::kWord32Or:
-      return VisitWordCompare(this, node, kArmOrr, cont, true, true);
+      return VisitBinop(this, node, kArmOrr, kArmOrr, cont);
     case IrOpcode::kWord32Xor:
-      return VisitWordCompare(this, node, kArmTeq, cont, true, false);
+      return VisitWordCompare(this, node, kArmTeq, cont, true);
     default:
       break;
   }
@@ -946,7 +918,7 @@ void InstructionSelector::VisitWord32Test(Node* node, FlagsContinuation* cont) {
 
 void InstructionSelector::VisitWord32Compare(Node* node,
                                              FlagsContinuation* cont) {
-  VisitWordCompare(this, node, kArmCmp, cont, false, false);
+  VisitWordCompare(this, node, kArmCmp, cont, false);
 }