[wasm] Int64Lowering of I64Shl on ia32.

src/compiler/int64-lowering.cc

Index: src/compiler/int64-lowering.cc
diff --git a/src/compiler/int64-lowering.cc b/src/compiler/int64-lowering.cc
index 0345d26d396d7364ac29be985ce47e8826083d41..253d2f0dc62df9f0eeb29ec744c2bd729c48336e 100644
--- a/src/compiler/int64-lowering.cc
+++ b/src/compiler/int64-lowering.cc
@@ -289,6 +289,28 @@ void Int64Lowering::LowerNode(Node* node) {
       break;
     }
     // kExprI64Shl:
+    case IrOpcode::kWord64Shl: {
+      // TODO(turbofan): if the shift count >= 32, then we can set the low word
+      // of the output to 0 and just calculate the high word.
+      DCHECK(node->InputCount() == 2);
+      Node* shift = node->InputAt(1);
+      if (HasReplacementLow(shift)) {
+        // We do not have to care about the high word replacement, because
+        // the shift can only be between 0 and 63 anyways.
+        node->ReplaceInput(1, GetReplacementLow(shift));
+      }
+
+      Node* value = node->InputAt(0);
+      node->ReplaceInput(0, GetReplacementLow(value));
+      node->InsertInput(zone(), 1, GetReplacementHigh(value));
+
+      NodeProperties::ChangeOp(node, machine()->Word32PairShl());
+      // We access the additional return values through projections.
+      Node* low_node = graph()->NewNode(common()->Projection(0), node);
+      Node* high_node = graph()->NewNode(common()->Projection(1), node);
+      ReplaceNode(node, low_node, high_node);
+      break;
+    }
     // kExprI64ShrU:
     // kExprI64ShrS:
     // kExprI64Eq: