[wasm] Int64Lowering of Int64Sub on ia32 and arm.

src/compiler/instruction-selector.cc

Index: src/compiler/instruction-selector.cc
diff --git a/src/compiler/instruction-selector.cc b/src/compiler/instruction-selector.cc
index 2b620a393b6a22911e323ae1716e0c647798fe20..91900be25c30dabec502028de1401680631509ae 100644
--- a/src/compiler/instruction-selector.cc
+++ b/src/compiler/instruction-selector.cc
@@ -1154,6 +1154,10 @@ void InstructionSelector::VisitNode(Node* node) {
       MarkAsWord32(NodeProperties::FindProjection(node, 0));
       MarkAsWord32(NodeProperties::FindProjection(node, 1));
       return VisitInt32PairAdd(node);
+    case IrOpcode::kInt32PairSub:
+      MarkAsWord32(NodeProperties::FindProjection(node, 0));
+      MarkAsWord32(NodeProperties::FindProjection(node, 1));
+      return VisitInt32PairSub(node);
     case IrOpcode::kWord32PairShl:
       MarkAsWord32(NodeProperties::FindProjection(node, 0));
       MarkAsWord32(NodeProperties::FindProjection(node, 1));
@@ -1389,10 +1393,12 @@ void InstructionSelector::VisitBitcastInt64ToFloat64(Node* node) {
 
 #endif  // V8_TARGET_ARCH_32_BIT
 
-// 32 bit targets do not implement the following instructions.
+// 64 bit targets do not implement the following instructions.
 #if V8_TARGET_ARCH_64_BIT
 void InstructionSelector::VisitInt32PairAdd(Node* node) { UNIMPLEMENTED(); }
 
+void InstructionSelector::VisitInt32PairSub(Node* node) { UNIMPLEMENTED(); }
+
 void InstructionSelector::VisitWord32PairShl(Node* node) { UNIMPLEMENTED(); }
 
 void InstructionSelector::VisitWord32PairShr(Node* node) { UNIMPLEMENTED(); }
@@ -1478,6 +1484,7 @@ void InstructionSelector::VisitProjection(Node* node) {
     case IrOpcode::kTryTruncateFloat32ToUint64:
     case IrOpcode::kTryTruncateFloat64ToUint64:
     case IrOpcode::kInt32PairAdd:
+    case IrOpcode::kInt32PairSub:
     case IrOpcode::kWord32PairShl:
     case IrOpcode::kWord32PairShr:
     case IrOpcode::kWord32PairSar: