[turbofan] Allow for 32-bit field offsets in store elimination.

src/compiler/store-store-elimination.cc

Index: src/compiler/store-store-elimination.cc
diff --git a/src/compiler/store-store-elimination.cc b/src/compiler/store-store-elimination.cc
index 98904b05b5d045c561c2d045cb6e2ee151f8473a..73efb5bd0ee9fbb8f9221f1c0b96220efeab062b 100644
--- a/src/compiler/store-store-elimination.cc
+++ b/src/compiler/store-store-elimination.cc
@@ -72,9 +72,8 @@ namespace compiler {
 
 namespace {
 
-// 16 bits was chosen fairly arbitrarily; it seems enough now. 8 bits is too
-// few.
-typedef uint16_t StoreOffset;
+// 4GiB ought to be enough for anybody.

[Jarin, 2016/08/19 09:30:35]

Just remove the comment.

[bgeron, 2016/08/19 10:42:10]

Done.

+typedef uint32_t StoreOffset;
 
 struct UnobservableStore {
   NodeId id_;
@@ -171,10 +170,10 @@ class RedundantStoreFinder final {
   const UnobservablesSet unobservables_visited_empty_;
 };
 
-// To safely cast an offset from a FieldAccess, which has a wider range
-// (namely int).
+// To safely cast an offset from a FieldAccess, which has a potentially wider
+// range (namely int).
 StoreOffset ToOffset(int offset) {
-  CHECK(0 <= offset && offset < (1 << 8 * sizeof(StoreOffset)));
+  CHECK(0 <= offset && (int64_t)offset < (1ll << 8 * sizeof(StoreOffset)));

[Jarin, 2016/08/19 09:30:35]

At this point, the upper bound check is useless, just remove it.

[bgeron, 2016/08/19 10:42:10]

Done.

   return (StoreOffset)offset;

[Jarin, 2016/08/19 09:30:35]

static_cast, please.

[bgeron, 2016/08/19 10:42:10]

Done.

 }