ARM64: Enable shorten-64-to-32 warning

src/arm64/utils-arm64.h

 // Copyright 2013 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_ARM64_UTILS_ARM64_H_
 #define V8_ARM64_UTILS_ARM64_H_
 
 #include <cmath>
 #include "src/v8.h"
 
@@ skipping 43 matching lines @@
 
 // Bit counting.
 int CountLeadingZeros(uint64_t value, int width);
 int CountLeadingSignBits(int64_t value, int width);
 int CountTrailingZeros(uint64_t value, int width);
 int CountSetBits(uint64_t value, int width);
 uint64_t LargestPowerOf2Divisor(uint64_t value);
 int MaskToBit(uint64_t mask);
 
 
+template <typename T>
+T ReverseBits(T value) {
+  DCHECK((sizeof(value) == 1) || (sizeof(value) == 2) || (sizeof(value) == 4) ||
+         (sizeof(value) == 8));
+  T result = 0;
+  for (unsigned i = 0; i < (sizeof(value) * 8); i++) {
+    result = (result << 1) | (value & 1);
+    value >>= 1;
+  }
+  return result;
+}
+
+
+template <typename T>
+T ReverseBytes(T value, int block_bytes_log2) {
+  DCHECK((sizeof(value) == 4) || (sizeof(value) == 8));
+  DCHECK((1U << block_bytes_log2) <= sizeof(value));
+  // Split the 64-bit value into an 8-bit array, where b[0] is the least
+  // significant byte, and b[7] is the most significant.
+  uint8_t bytes[8];
+  uint64_t mask = 0xff00000000000000;
+  for (int i = 7; i >= 0; i--) {
+    bytes[i] = (static_cast<uint64_t>(value) & mask) >> (i * 8);
+    mask >>= 8;
+  }
+
+  // Permutation tables for REV instructions.
+  //  permute_table[0] is used by REV16_x, REV16_w
+  //  permute_table[1] is used by REV32_x, REV_w
+  //  permute_table[2] is used by REV_x
+  DCHECK((0 < block_bytes_log2) && (block_bytes_log2 < 4));
+  static const uint8_t permute_table[3][8] = {{6, 7, 4, 5, 2, 3, 0, 1},
+                                              {4, 5, 6, 7, 0, 1, 2, 3},
+                                              {0, 1, 2, 3, 4, 5, 6, 7}};
+  T result = 0;
+  for (int i = 0; i < 8; i++) {
+    result <<= 8;
+    result |= bytes[permute_table[block_bytes_log2 - 1][i]];
+  }
+  return result;
+}
+
+
 // NaN tests.
 inline bool IsSignallingNaN(double num) {
   uint64_t raw = double_to_rawbits(num);
   if (std::isnan(num) && ((raw & kDQuietNanMask) == 0)) {
     return true;
   }
   return false;
 }
 
 
@@ skipping 31 matching lines @@
 }
 
 
 inline float FusedMultiplyAdd(float op1, float op2, float a) {
   return fmaf(op1, op2, a);
 }
 
 } }  // namespace v8::internal
 
 #endif  // V8_ARM64_UTILS_ARM64_H_