[turbofan] Add Int64(Add|Sub)WithOverflow support.

src/base/bits.h

 // Copyright 2014 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_BASE_BITS_H_
 #define V8_BASE_BITS_H_
 
 #include <stdint.h>
 #include "src/base/macros.h"
 #if V8_CC_MSVC
@@ skipping 194 matching lines @@
 #if V8_HAS_BUILTIN_SSUB_OVERFLOW
   return __builtin_ssub_overflow(lhs, rhs, val);
 #else
   uint32_t res = static_cast<uint32_t>(lhs) - static_cast<uint32_t>(rhs);
   *val = bit_cast<int32_t>(res);
   return ((res ^ lhs) & (res ^ ~rhs) & (1U << 31)) != 0;
 #endif
 }
 
 
+// SignedAddOverflow64(lhs,rhs,val) performs a signed summation of |lhs| and
+// |rhs| and stores the result into the variable pointed to by |val| and
+// returns true if the signed summation resulted in an overflow.
+inline bool SignedAddOverflow64(int64_t lhs, int64_t rhs, int64_t* val) {
+  uint64_t res = static_cast<uint64_t>(lhs) + static_cast<uint64_t>(rhs);
+  *val = bit_cast<int64_t>(res);
+  return ((res ^ lhs) & (res ^ rhs) & (1ULL << 63)) != 0;
+}
+
+
+// SignedSubOverflow64(lhs,rhs,val) performs a signed subtraction of |lhs| and
+// |rhs| and stores the result into the variable pointed to by |val| and
+// returns true if the signed subtraction resulted in an overflow.
+inline bool SignedSubOverflow64(int64_t lhs, int64_t rhs, int64_t* val) {
+  uint64_t res = static_cast<uint64_t>(lhs) - static_cast<uint64_t>(rhs);
+  *val = bit_cast<int64_t>(res);
+  return ((res ^ lhs) & (res ^ ~rhs) & (1ULL << 63)) != 0;
+}
+
+
 // SignedMulHigh32(lhs, rhs) multiplies two signed 32-bit values |lhs| and
 // |rhs|, extracts the most significant 32 bits of the result, and returns
 // those.
 int32_t SignedMulHigh32(int32_t lhs, int32_t rhs);
 
 
 // SignedMulHighAndAdd32(lhs, rhs, acc) multiplies two signed 32-bit values
 // |lhs| and |rhs|, extracts the most significant 32 bits of the result, and
 // adds the accumulate value |acc|.
 int32_t SignedMulHighAndAdd32(int32_t lhs, int32_t rhs, int32_t acc);
@@ skipping 35 matching lines @@
 // truncated to uint32. If |rhs| is zero, then zero is returned.
 inline uint32_t UnsignedMod32(uint32_t lhs, uint32_t rhs) {
   return rhs ? lhs % rhs : 0u;
 }
 
 }  // namespace bits
 }  // namespace base
 }  // namespace v8
 
 #endif  // V8_BASE_BITS_H_