[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..34f0cf6d018d7dc18ba338ce8c66fbd48919a9fa 100644
--- a/src/compiler/arm/instruction-selector-arm.cc
+++ b/src/compiler/arm/instruction-selector-arm.cc
@@ -957,47 +957,74 @@ 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);
+  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 {
+    // 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)));
+  }
 }
 
 void InstructionSelector::VisitWord32PairShl(Node* node) {
@@ -1016,9 +1043,11 @@ void InstructionSelector::VisitWord32PairShl(Node* node) {
                                  g.UseRegister(node->InputAt(1)),
                                  shift_operand};
 
+  Node* projection1 = NodeProperties::FindProjection(node, 1);
+
   InstructionOperand outputs[] = {
       g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+      projection1 ? g.DefineAsRegister(projection1) : g.TempRegister()};
 
   Emit(kArmLslPair, 2, outputs, 3, inputs);
 }
@@ -1039,9 +1068,11 @@ void InstructionSelector::VisitWord32PairShr(Node* node) {
                                  g.UseUniqueRegister(node->InputAt(1)),
                                  shift_operand};
 
+  Node* projection1 = NodeProperties::FindProjection(node, 1);
+
   InstructionOperand outputs[] = {
       g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+      projection1 ? g.DefineAsRegister(projection1) : g.TempRegister()};
 
   Emit(kArmLsrPair, 2, outputs, 3, inputs);
 }
@@ -1062,9 +1093,11 @@ void InstructionSelector::VisitWord32PairSar(Node* node) {
                                  g.UseUniqueRegister(node->InputAt(1)),
                                  shift_operand};
 
+  Node* projection1 = NodeProperties::FindProjection(node, 1);
+
   InstructionOperand outputs[] = {
       g.DefineAsRegister(node),
-      g.DefineAsRegister(NodeProperties::FindProjection(node, 1))};
+      projection1 ? g.DefineAsRegister(projection1) : g.TempRegister()};
 
   Emit(kArmAsrPair, 2, outputs, 3, inputs);
 }