[turbofan] Some strength reduction on Smi/HeapObject checks.

src/globals.h

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef V8_GLOBALS_H_
 #define V8_GLOBALS_H_
 
 #include <stddef.h>
 #include <stdint.h>
 
@@ skipping 442 matching lines @@
 const int kSpaceTagSize = 3;
 const int kSpaceTagMask = (1 << kSpaceTagSize) - 1;
 
 enum AllocationAlignment {
   kWordAligned,
   kDoubleAligned,
   kDoubleUnaligned,
   kSimd128Unaligned
 };
 
+// Possible outcomes for decisions.
+enum class Decision : uint8_t { kUnknown, kTrue, kFalse };
+
+inline size_t hash_value(Decision decision) {
+  return static_cast<uint8_t>(decision);
+}
+
+inline std::ostream& operator<<(std::ostream& os, Decision decision) {
+  switch (decision) {
+    case Decision::kUnknown:
+      return os << "Unknown";
+    case Decision::kTrue:
+      return os << "True";
+    case Decision::kFalse:
+      return os << "False";
+  }
+  UNREACHABLE();
+  return os;
+}
+
 // Supported write barrier modes.
 enum WriteBarrierKind : uint8_t {
   kNoWriteBarrier,
   kMapWriteBarrier,
   kPointerWriteBarrier,
   kFullWriteBarrier
 };
 
 inline size_t hash_value(WriteBarrierKind kind) {
   return static_cast<uint8_t>(kind);
@@ skipping 620 matching lines @@
   return static_cast<uint32_t>(bit_cast<uintptr_t>(address) >>
                                kPointerSizeLog2);
 }
 
 }  // namespace internal
 }  // namespace v8
 
 namespace i = v8::internal;
 
 #endif  // V8_GLOBALS_H_