[turbofan] Add backend support for float32.

src/compiler/js-typed-lowering.cc

Index: src/compiler/js-typed-lowering.cc
diff --git a/src/compiler/js-typed-lowering.cc b/src/compiler/js-typed-lowering.cc
index be125342eaed0cc683322c7ccf19ecb3bc4bd79f..8fe899cd2fd3ef14a46d6e859d33db022b6e566c 100644
--- a/src/compiler/js-typed-lowering.cc
+++ b/src/compiler/js-typed-lowering.cc
@@ -559,6 +559,14 @@ Reduction JSTypedLowering::ReduceJSLoadProperty(Node* node) {
         graph()->NewNode(simplified()->LoadElement(element_access), elements,
                          key, jsgraph()->Uint32Constant(length),
                          NodeProperties::GetEffectInput(node));
+    // TODO(titzer): Remove this hack once float32 is properly supported in
+    // simplified lowering.
+    if (element_access.machine_type == kRepFloat32) {
+      Node* change =
+          graph()->NewNode(machine()->ChangeFloat32ToFloat64(), value);
+      NodeProperties::ReplaceWithValue(node, change, value);
+      return Changed(value);
+    }
     return ReplaceEagerly(node, value);
   }
   return NoChange();
@@ -602,6 +610,11 @@ Reduction JSTypedLowering::ReduceJSStoreProperty(Node* node) {
                                     NodeProperties::GetControlInput(node));
 
     Node* if_true = graph()->NewNode(common()->IfTrue(), branch);
+    // TODO(titzer): Remove this hack once float32 is properly supported in
+    // simplified lowering.
+    if (element_access.machine_type == kRepFloat32) {
+      value = graph()->NewNode(machine()->TruncateFloat64ToFloat32(), value);
+    }
     Node* store =
         graph()->NewNode(simplified()->StoreElement(element_access), elements,
                          key, jsgraph()->Uint32Constant(length), value,