Upgrade V8 to 5.1.281.57 DO NOT MERGE
FPIIM-449
Change-Id: Id981b686b4d587ac31697662eb98bb34be42ad90
(cherry picked from commit 3b9bc31999c9787eb726ecdbfd5796bfdec32a18)
diff --git a/src/compiler/load-elimination.cc b/src/compiler/load-elimination.cc
index 97f1ab0..e19368d 100644
--- a/src/compiler/load-elimination.cc
+++ b/src/compiler/load-elimination.cc
@@ -4,8 +4,11 @@
#include "src/compiler/load-elimination.h"
+#include "src/compiler/common-operator.h"
+#include "src/compiler/graph.h"
#include "src/compiler/node-properties.h"
#include "src/compiler/simplified-operator.h"
+#include "src/types.h"
namespace v8 {
namespace internal {
@@ -13,7 +16,6 @@
LoadElimination::~LoadElimination() {}
-
Reduction LoadElimination::Reduce(Node* node) {
switch (node->opcode()) {
case IrOpcode::kLoadField:
@@ -24,7 +26,6 @@
return NoChange();
}
-
Reduction LoadElimination::ReduceLoadField(Node* node) {
DCHECK_EQ(IrOpcode::kLoadField, node->opcode());
FieldAccess const access = FieldAccessOf(node->op());
@@ -45,8 +46,22 @@
if (access == FieldAccessOf(effect->op())) {
if (object == NodeProperties::GetValueInput(effect, 0)) {
Node* const value = NodeProperties::GetValueInput(effect, 1);
- ReplaceWithValue(node, value);
- return Replace(value);
+ Type* stored_value_type = NodeProperties::GetType(value);
+ Type* load_type = NodeProperties::GetType(node);
+ // Make sure the replacement's type is a subtype of the node's
+ // type. Otherwise we could confuse optimizations that were
+ // based on the original type.
+ if (stored_value_type->Is(load_type)) {
+ ReplaceWithValue(node, value);
+ return Replace(value);
+ } else {
+ Node* renamed = graph()->NewNode(
+ common()->Guard(Type::Intersect(stored_value_type, load_type,
+ graph()->zone())),
+ value, NodeProperties::GetControlInput(node));
+ ReplaceWithValue(node, renamed);
+ return Replace(renamed);
+ }
}
// TODO(turbofan): Alias analysis to the rescue?
return NoChange();