[turbofan] Remove Truncation::Word64().

This truncation doesn't have a proper meaning anyways and has never been
used inside the representation selection. For pointer fields we also
don't need to pass on a truncation anyways.

Bug: v8:8015
Change-Id: I5ff49e20b70fa70d6bcf7401a357cd7ad9f1a938
Reviewed-on: https://chromium-review.googlesource.com/1226870
Commit-Queue: Benedikt Meurer <bmeurer@chromium.org>
Reviewed-by: Jaroslav Sevcik <jarin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#55885}

src/compiler/representation-change.cc

@@ -24,8 +24,6 @@ const char* Truncation::description() const {
       return "truncate-to-bool";
     case TruncationKind::kWord32:
       return "truncate-to-word32";
-    case TruncationKind::kWord64:
-      return "truncate-to-word64";
     case TruncationKind::kFloat64:
       switch (identify_zeros()) {
         case kIdentifyZeros:
@@ -44,23 +42,22 @@ const char* Truncation::description() const {
   UNREACHABLE();
 }
 
-
 // Partial order for truncations:
 //
-//  kWord64       kAny <-------+
-//     ^            ^          |
-//     \            |          |
-//      \         kFloat64     |
-//       \        ^            |
-//        \       /            |
-//         kWord32           kBool
-//               ^            ^
-//               \            /
-//                \          /
-//                 \        /
-//                  \      /
-//                   \    /
-//                   kNone
+//          kAny <-------+
+//            ^          |
+//            |          |
+//          kFloat64     |
+//          ^            |
+//          /            |
+//   kWord32           kBool
+//         ^            ^
+//         \            /
+//          \          /
+//           \        /
+//            \      /
+//             \    /
+//             kNone
 //
 // TODO(jarin) We might consider making kBool < kFloat64.
 
@@ -103,10 +100,7 @@ bool Truncation::LessGeneral(TruncationKind rep1, TruncationKind rep2) {
       return rep2 == TruncationKind::kBool || rep2 == TruncationKind::kAny;
     case TruncationKind::kWord32:
       return rep2 == TruncationKind::kWord32 ||
-             rep2 == TruncationKind::kWord64 ||
              rep2 == TruncationKind::kFloat64 || rep2 == TruncationKind::kAny;
-    case TruncationKind::kWord64:
-      return rep2 == TruncationKind::kWord64;
     case TruncationKind::kFloat64:
       return rep2 == TruncationKind::kFloat64 || rep2 == TruncationKind::kAny;
     case TruncationKind::kAny:

src/compiler/representation-change.h

@@ -26,9 +26,6 @@ class Truncation final {
   static Truncation Word32() {
     return Truncation(TruncationKind::kWord32, kIdentifyZeros);
   }
-  static Truncation Word64() {
-    return Truncation(TruncationKind::kWord64, kIdentifyZeros);
-  }
   static Truncation Float64(IdentifyZeros identify_zeros = kDistinguishZeros) {
     return Truncation(TruncationKind::kFloat64, identify_zeros);
   }
@@ -57,10 +54,6 @@ class Truncation final {
     return LessGeneral(kind_, TruncationKind::kWord32) ||
            LessGeneral(kind_, TruncationKind::kBool);
   }
-  bool IdentifiesUndefinedAndNaN() {
-    return LessGeneral(kind_, TruncationKind::kFloat64) ||
-           LessGeneral(kind_, TruncationKind::kWord64);
-  }
   bool IdentifiesZeroAndMinusZero() const {
     return identify_zeros() == kIdentifyZeros;
   }
@@ -85,7 +78,6 @@ class Truncation final {
     kNone,
     kBool,
     kWord32,
-    kWord64,
     kFloat64,
     kAny
   };
@@ -162,8 +154,11 @@ class UseInfo {
   static UseInfo TruncatingWord32() {
     return UseInfo(MachineRepresentation::kWord32, Truncation::Word32());
   }
-  static UseInfo TruncatingWord64() {
-    return UseInfo(MachineRepresentation::kWord64, Truncation::Word64());
+  static UseInfo Word64() {
+    return UseInfo(MachineRepresentation::kWord64, Truncation::Any());
+  }
+  static UseInfo Word() {
+    return UseInfo(MachineType::PointerRepresentation(), Truncation::Any());
   }
   static UseInfo Bool() {
     return UseInfo(MachineRepresentation::kBit, Truncation::Bool());
@@ -174,9 +169,6 @@ class UseInfo {
   static UseInfo TruncatingFloat64() {
     return UseInfo(MachineRepresentation::kFloat64, Truncation::Float64());
   }
-  static UseInfo PointerInt() {
-    return kPointerSize == 4 ? TruncatingWord32() : TruncatingWord64();
-  }
   static UseInfo AnyTagged() {
     return UseInfo(MachineRepresentation::kTagged, Truncation::Any());
   }

src/compiler/simplified-lowering.cc

@@ -140,7 +140,7 @@ UseInfo TruncatingUseInfoFromRepresentation(MachineRepresentation rep) {
     case MachineRepresentation::kWord32:
       return UseInfo::TruncatingWord32();
     case MachineRepresentation::kWord64:
-      return UseInfo::TruncatingWord64();
+      return UseInfo::Word64();
     case MachineRepresentation::kBit:
       return UseInfo::Bool();
     case MachineRepresentation::kSimd128:
@@ -151,11 +151,11 @@ UseInfo TruncatingUseInfoFromRepresentation(MachineRepresentation rep) {
 }
 
 UseInfo UseInfoForBasePointer(const FieldAccess& access) {
-  return access.tag() != 0 ? UseInfo::AnyTagged() : UseInfo::PointerInt();
+  return access.tag() != 0 ? UseInfo::AnyTagged() : UseInfo::Word();
 }
 
 UseInfo UseInfoForBasePointer(const ElementAccess& access) {
-  return access.tag() != 0 ? UseInfo::AnyTagged() : UseInfo::PointerInt();
+  return access.tag() != 0 ? UseInfo::AnyTagged() : UseInfo::Word();
 }
 
 void ReplaceEffectControlUses(Node* node, Node* effect, Node* control) {
@@ -2637,7 +2637,7 @@ class RepresentationSelector {
             MachineRepresentationFromArrayType(ExternalArrayTypeOf(node->op()));
         ProcessInput(node, 0, UseInfo::AnyTagged());         // buffer
         ProcessInput(node, 1, UseInfo::AnyTagged());         // base pointer
-        ProcessInput(node, 2, UseInfo::PointerInt());        // external pointer
+        ProcessInput(node, 2, UseInfo::Word());              // external pointer
         ProcessInput(node, 3, UseInfo::TruncatingWord32());  // index
         ProcessRemainingInputs(node, 4);
         SetOutput(node, rep);
@@ -2647,7 +2647,7 @@ class RepresentationSelector {
         MachineRepresentation const rep =
             MachineRepresentationFromArrayType(ExternalArrayTypeOf(node->op()));
         ProcessInput(node, 0, UseInfo::AnyTagged());         // buffer
-        ProcessInput(node, 1, UseInfo::PointerInt());        // external pointer
+        ProcessInput(node, 1, UseInfo::Word());              // external pointer
         ProcessInput(node, 2, UseInfo::TruncatingWord32());  // index
         ProcessInput(node, 3, UseInfo::Bool());              // little-endian
         ProcessRemainingInputs(node, 4);
@@ -2659,7 +2659,7 @@ class RepresentationSelector {
             MachineRepresentationFromArrayType(ExternalArrayTypeOf(node->op()));
         ProcessInput(node, 0, UseInfo::AnyTagged());         // buffer
         ProcessInput(node, 1, UseInfo::AnyTagged());         // base pointer
-        ProcessInput(node, 2, UseInfo::PointerInt());        // external pointer
+        ProcessInput(node, 2, UseInfo::Word());              // external pointer
         ProcessInput(node, 3, UseInfo::TruncatingWord32());  // index
         ProcessInput(node, 4,
                      TruncatingUseInfoFromRepresentation(rep));  // value
@@ -2671,7 +2671,7 @@ class RepresentationSelector {
         MachineRepresentation const rep =
             MachineRepresentationFromArrayType(ExternalArrayTypeOf(node->op()));
         ProcessInput(node, 0, UseInfo::AnyTagged());         // buffer
-        ProcessInput(node, 1, UseInfo::PointerInt());        // external pointer
+        ProcessInput(node, 1, UseInfo::Word());              // external pointer
         ProcessInput(node, 2, UseInfo::TruncatingWord32());  // index
         ProcessInput(node, 3,
                      TruncatingUseInfoFromRepresentation(rep));  // value
@@ -2961,8 +2961,7 @@ class RepresentationSelector {
         return;
       }
       case IrOpcode::kArgumentsLength: {
-        VisitUnop(node, UseInfo::PointerInt(),
-                  MachineRepresentation::kTaggedSigned);
+        VisitUnop(node, UseInfo::Word(), MachineRepresentation::kTaggedSigned);
         return;
       }
       case IrOpcode::kNewDoubleElements:
@@ -2972,7 +2971,7 @@ class RepresentationSelector {
         return;
       }
       case IrOpcode::kNewArgumentsElements: {
-        VisitBinop(node, UseInfo::PointerInt(), UseInfo::TaggedSigned(),
+        VisitBinop(node, UseInfo::Word(), UseInfo::TaggedSigned(),
                    MachineRepresentation::kTaggedPointer);
         return;
       }