[wasm] Trim graph before scheduling.

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 ceb5b2507f809d912dd4268a3937462274428786..a2f2d23f7c40aa9448ecd5381cf4723571138970 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -957,76 +957,83 @@ void InstructionSelector::VisitWord32Sar(Node* node) {
 void InstructionSelector::VisitInt32PairAdd(Node* node) {
   ArmOperandGenerator g(this);
 
-  // We use UseUniqueRegister here to avoid register sharing with the output
-  // registers.
-  InstructionOperand inputs[] = {
-      g.UseRegister(node->InputAt(0)), g.UseUniqueRegister(node->InputAt(1)),
-      g.UseRegister(node->InputAt(2)), g.UseUniqueRegister(node->InputAt(3))};
-
-  InstructionOperand outputs[] = {
-      g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
-
-  Emit(kArmAddPair, 2, outputs, 4, inputs);
+  Node* projection1 = NodeProperties::FindProjection(node, 1);
+  if (projection1) {
+    // We use UseUniqueRegister here to avoid register sharing with the output
+    // registers.
+    InstructionOperand inputs[] = {
+        g.UseRegister(node->InputAt(0)), g.UseUniqueRegister(node->InputAt(1)),
+        g.UseRegister(node->InputAt(2)), g.UseUniqueRegister(node->InputAt(3))};
+
+    InstructionOperand outputs[] = {
+        g.DefineAsRegister(node),
+        g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+
+    Emit(kArmAddPair, 2, outputs, 4, inputs);
+  } else {
+    // The high word of the result is not used, so we emit the standard 32 bit
+    // instruction.
+    Emit(kArmAdd | AddressingModeField::encode(kMode_Operand2_R),
+         g.DefineSameAsFirst(node), g.UseRegister(node->InputAt(0)),
+         g.UseRegister(node->InputAt(2)));
+  }
 }
 
 void InstructionSelector::VisitInt32PairSub(Node* node) {
   ArmOperandGenerator g(this);
 
-  // We use UseUniqueRegister here to avoid register sharing with the output
-  // register.
-  InstructionOperand inputs[] = {
-      g.UseRegister(node->InputAt(0)), g.UseUniqueRegister(node->InputAt(1)),
-      g.UseRegister(node->InputAt(2)), g.UseUniqueRegister(node->InputAt(3))};
+  Node* projection1 = NodeProperties::FindProjection(node, 1);
+  if (projection1) {
+    // We use UseUniqueRegister here to avoid register sharing with the output
+    // register.
+    InstructionOperand inputs[] = {
+        g.UseRegister(node->InputAt(0)), g.UseUniqueRegister(node->InputAt(1)),
+        g.UseRegister(node->InputAt(2)), g.UseUniqueRegister(node->InputAt(3))};
 
-  InstructionOperand outputs[] = {
-      g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+    InstructionOperand outputs[] = {
+        g.DefineAsRegister(node),
+        g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
 
-  Emit(kArmSubPair, 2, outputs, 4, inputs);
+    Emit(kArmSubPair, 2, outputs, 4, inputs);
+  } else {
+    // The high word of the result is not used, so we emit the standard 32 bit
+    // instruction.
+    Emit(kArmSub | AddressingModeField::encode(kMode_Operand2_R),
+         g.DefineSameAsFirst(node), g.UseRegister(node->InputAt(0)),
+         g.UseRegister(node->InputAt(2)));
+  }
 }
 
 void InstructionSelector::VisitInt32PairMul(Node* node) {
   ArmOperandGenerator g(this);
-  InstructionOperand inputs[] = {g.UseUniqueRegister(node->InputAt(0)),
-                                 g.UseUniqueRegister(node->InputAt(1)),
-                                 g.UseUniqueRegister(node->InputAt(2)),
-                                 g.UseUniqueRegister(node->InputAt(3))};
-
-  InstructionOperand outputs[] = {
-      g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
-
-  Emit(kArmMulPair, 2, outputs, 4, inputs);
-}
-
-void InstructionSelector::VisitWord32PairShl(Node* node) {
-  ArmOperandGenerator g(this);
-  // We use g.UseUniqueRegister here for InputAt(0) to guarantee that there is
-  // no register aliasing with output registers.
-  Int32Matcher m(node->InputAt(2));
-  InstructionOperand shift_operand;
-  if (m.HasValue()) {
-    shift_operand = g.UseImmediate(m.node());
+  Node* projection1 = NodeProperties::FindProjection(node, 1);
+  if (projection1) {
+    InstructionOperand inputs[] = {g.UseUniqueRegister(node->InputAt(0)),
+                                   g.UseUniqueRegister(node->InputAt(1)),
+                                   g.UseUniqueRegister(node->InputAt(2)),
+                                   g.UseUniqueRegister(node->InputAt(3))};
+
+    InstructionOperand outputs[] = {
+        g.DefineAsRegister(node),
+        g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+
+    Emit(kArmMulPair, 2, outputs, 4, inputs);
   } else {
-    shift_operand = g.UseUniqueRegister(m.node());
+    // The high word of the result is not used, so we emit the standard 32 bit
+    // instruction.
+    Emit(kArmMul | AddressingModeField::encode(kMode_Operand2_R),
+         g.DefineSameAsFirst(node), g.UseRegister(node->InputAt(0)),
+         g.UseRegister(node->InputAt(2)));
   }
-
-  InstructionOperand inputs[] = {g.UseUniqueRegister(node->InputAt(0)),
-                                 g.UseRegister(node->InputAt(1)),
-                                 shift_operand};
-
-  InstructionOperand outputs[] = {
-      g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
-
-  Emit(kArmLslPair, 2, outputs, 3, inputs);
 }
 
-void InstructionSelector::VisitWord32PairShr(Node* node) {
-  ArmOperandGenerator g(this);
-  // We use g.UseUniqueRegister here for InputAt(1) and InputAt(2) to to
-  // guarantee that there is no register aliasing with output register.
+namespace {
+// Shared routine for multiple shift operations.
+void VisitWord32PairShift(InstructionSelector* selector, InstructionCode opcode,
+                          Node* node) {
+  ArmOperandGenerator g(selector);
+  // We use g.UseUniqueRegister here to guarantee that there is
+  // no register aliasing of input registers with output registers.
   Int32Matcher m(node->InputAt(2));
   InstructionOperand shift_operand;
   if (m.HasValue()) {
@@ -1035,38 +1042,37 @@ void InstructionSelector::VisitWord32PairShr(Node* node) {
     shift_operand = g.UseUniqueRegister(m.node());
   }
 
-  InstructionOperand inputs[] = {g.UseRegister(node->InputAt(0)),
+  InstructionOperand inputs[] = {g.UseUniqueRegister(node->InputAt(0)),
                                  g.UseUniqueRegister(node->InputAt(1)),
                                  shift_operand};
 
-  InstructionOperand outputs[] = {
-      g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+  Node* projection1 = NodeProperties::FindProjection(node, 1);
 
-  Emit(kArmLsrPair, 2, outputs, 3, inputs);
-}
+  InstructionOperand outputs[2];
+  InstructionOperand temps[1];
+  int32_t output_count = 0;
+  int32_t temp_count = 0;
 
-void InstructionSelector::VisitWord32PairSar(Node* node) {
-  ArmOperandGenerator g(this);
-  // We use g.UseUniqueRegister here for InputAt(1) and InputAt(2) to to
-  // guarantee that there is no register aliasing with output register.
-  Int32Matcher m(node->InputAt(2));
-  InstructionOperand shift_operand;
-  if (m.HasValue()) {
-    shift_operand = g.UseImmediate(m.node());
+  outputs[output_count++] = g.DefineAsRegister(node);
+  if (projection1) {
+    outputs[output_count++] = g.DefineAsRegister(projection1);
   } else {
-    shift_operand = g.UseUniqueRegister(m.node());
+    temps[temp_count++] = g.TempRegister();
   }
 
-  InstructionOperand inputs[] = {g.UseRegister(node->InputAt(0)),
-                                 g.UseUniqueRegister(node->InputAt(1)),
-                                 shift_operand};
+  selector->Emit(opcode, output_count, outputs, 3, inputs, temp_count, temps);
+}
+}  // namespace
+void InstructionSelector::VisitWord32PairShl(Node* node) {
+  VisitWord32PairShift(this, kArmLslPair, node);
+}
 
-  InstructionOperand outputs[] = {
-      g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+void InstructionSelector::VisitWord32PairShr(Node* node) {
+  VisitWord32PairShift(this, kArmLsrPair, node);
+}
 
-  Emit(kArmAsrPair, 2, outputs, 3, inputs);
+void InstructionSelector::VisitWord32PairSar(Node* node) {
+  VisitWord32PairShift(this, kArmAsrPair, node);
 }
 
 void InstructionSelector::VisitWord32Ror(Node* node) {