[turbofan] Add support for accessing Uint8ClampedArrays.

src/compiler/simplified-lowering.cc

Index: src/compiler/simplified-lowering.cc
diff --git a/src/compiler/simplified-lowering.cc b/src/compiler/simplified-lowering.cc
index 9555a3fe00a5dc9e46884420bf488e2d68311957..ca3ed1f75909630d9ae5f3a7757ad90c181f9203 100644
--- a/src/compiler/simplified-lowering.cc
+++ b/src/compiler/simplified-lowering.cc
@@ -2111,6 +2111,31 @@ class RepresentationSelector {
         if (lower()) DeferReplacement(node, node->InputAt(0));
         return;
       }
+      case IrOpcode::kNumberToUint8Clamped: {
+        Type* const input_type = TypeOf(node->InputAt(0));
+        if (input_type->Is(type_cache_.kUint8OrMinusZeroOrNaN)) {
+          VisitUnop(node, UseInfo::TruncatingWord32(),
+                    MachineRepresentation::kWord32);
+          if (lower()) DeferReplacement(node, node->InputAt(0));
+        } else if (input_type->Is(Type::Unsigned32OrMinusZeroOrNaN())) {
+          VisitUnop(node, UseInfo::TruncatingWord32(),
+                    MachineRepresentation::kWord32);
+          if (lower()) lowering->DoUnsigned32ToUint8Clamped(node);
+        } else if (input_type->Is(Type::Signed32OrMinusZeroOrNaN())) {
+          VisitUnop(node, UseInfo::TruncatingWord32(),
+                    MachineRepresentation::kWord32);
+          if (lower()) lowering->DoSigned32ToUint8Clamped(node);
+        } else if (input_type->Is(type_cache_.kIntegerOrMinusZeroOrNaN)) {
+          VisitUnop(node, UseInfo::TruncatingFloat64(),
+                    MachineRepresentation::kFloat64);
+          if (lower()) lowering->DoIntegerToUint8Clamped(node);
+        } else {
+          VisitUnop(node, UseInfo::TruncatingFloat64(),
+                    MachineRepresentation::kFloat64);
+          if (lower()) lowering->DoNumberToUint8Clamped(node);
+        }
+        return;
+      }
       case IrOpcode::kReferenceEqual: {
         VisitBinop(node, UseInfo::AnyTagged(), MachineRepresentation::kBit);
         if (lower()) {
@@ -3294,6 +3319,71 @@ void SimplifiedLowering::DoNumberToBit(Node* node) {
   NodeProperties::ChangeOp(node, machine()->Float64LessThan());
 }
 
+void SimplifiedLowering::DoIntegerToUint8Clamped(Node* node) {
+  Node* const input = node->InputAt(0);
+  Node* const min = jsgraph()->Float64Constant(0.0);
+  Node* const max = jsgraph()->Float64Constant(255.0);
+
+  node->ReplaceInput(
+      0, graph()->NewNode(machine()->Float64LessThan(), min, input));
+  node->AppendInput(
+      graph()->zone(),
+      graph()->NewNode(
+          common()->Select(MachineRepresentation::kFloat64),
+          graph()->NewNode(machine()->Float64LessThan(), input, max), input,
+          max));
+  node->AppendInput(graph()->zone(), min);
+  NodeProperties::ChangeOp(node,
+                           common()->Select(MachineRepresentation::kFloat64));
+}
+
+void SimplifiedLowering::DoNumberToUint8Clamped(Node* node) {
+  Node* const input = node->InputAt(0);
+  Node* const min = jsgraph()->Float64Constant(0.0);
+  Node* const max = jsgraph()->Float64Constant(255.0);
+
+  node->ReplaceInput(
+      0, graph()->NewNode(
+             common()->Select(MachineRepresentation::kFloat64),
+             graph()->NewNode(machine()->Float64LessThan(), min, input),
+             graph()->NewNode(
+                 common()->Select(MachineRepresentation::kFloat64),
+                 graph()->NewNode(machine()->Float64LessThan(), input, max),
+                 input, max),
+             min));
+  NodeProperties::ChangeOp(node,
+                           machine()->Float64RoundTiesEven().placeholder());
+}
+
+void SimplifiedLowering::DoSigned32ToUint8Clamped(Node* node) {
+  Node* const input = node->InputAt(0);
+  Node* const min = jsgraph()->Int32Constant(0);
+  Node* const max = jsgraph()->Int32Constant(255);
+
+  node->ReplaceInput(
+      0, graph()->NewNode(machine()->Int32LessThanOrEqual(), input, max));
+  node->AppendInput(
+      graph()->zone(),
+      graph()->NewNode(common()->Select(MachineRepresentation::kWord32),
+                       graph()->NewNode(machine()->Int32LessThan(), input, min),
+                       min, input));
+  node->AppendInput(graph()->zone(), max);
+  NodeProperties::ChangeOp(node,
+                           common()->Select(MachineRepresentation::kWord32));
+}
+
+void SimplifiedLowering::DoUnsigned32ToUint8Clamped(Node* node) {
+  Node* const input = node->InputAt(0);
+  Node* const max = jsgraph()->Uint32Constant(255u);
+
+  node->ReplaceInput(
+      0, graph()->NewNode(machine()->Uint32LessThanOrEqual(), input, max));
+  node->AppendInput(graph()->zone(), input);
+  node->AppendInput(graph()->zone(), max);
+  NodeProperties::ChangeOp(node,
+                           common()->Select(MachineRepresentation::kWord32));
+}
+
 Node* SimplifiedLowering::ToNumberCode() {
   if (!to_number_code_.is_set()) {
     Callable callable = CodeFactory::ToNumber(isolate());