diff --git a/deps/v8/src/regexp-macro-assembler-tracer.cc b/deps/v8/src/regexp-macro-assembler-tracer.cc
index b32d71dba5..0a638e7320 100644
--- a/deps/v8/src/regexp-macro-assembler-tracer.cc
+++ b/deps/v8/src/regexp-macro-assembler-tracer.cc
@@ -37,8 +37,8 @@ RegExpMacroAssemblerTracer::RegExpMacroAssemblerTracer(
     RegExpMacroAssembler* assembler) :
   assembler_(assembler) {
   unsigned int type = assembler->Implementation();
-  ASSERT(type < 4);
-  const char* impl_names[4] = {"IA32", "ARM", "X64", "Bytecode"};
+  ASSERT(type < 5);
+  const char* impl_names[4] = {"IA32", "ARM", "MIPS", "X64", "Bytecode"};
   PrintF("RegExpMacroAssembler%s();\n", impl_names[type]);
 }
 
diff --git a/deps/v8/src/x64/regexp-macro-assembler-x64.cc b/deps/v8/src/x64/regexp-macro-assembler-x64.cc
index a782bd7052..6ba4a68275 100644
--- a/deps/v8/src/x64/regexp-macro-assembler-x64.cc
+++ b/deps/v8/src/x64/regexp-macro-assembler-x64.cc
@@ -193,7 +193,7 @@ void RegExpMacroAssemblerX64::CheckCharacterGT(uc16 limit, Label* on_greater) {
 void RegExpMacroAssemblerX64::CheckAtStart(Label* on_at_start) {
   Label not_at_start;
   // Did we start the match at the start of the string at all?
-  __ cmpb(Operand(rbp, kStartIndex), Immediate(0));
+  __ cmpl(Operand(rbp, kStartIndex), Immediate(0));
   BranchOrBacktrack(not_equal, &not_at_start);
   // If we did, are we still at the start of the input?
   __ lea(rax, Operand(rsi, rdi, times_1, 0));
@@ -205,7 +205,7 @@ void RegExpMacroAssemblerX64::CheckAtStart(Label* on_at_start) {
 
 void RegExpMacroAssemblerX64::CheckNotAtStart(Label* on_not_at_start) {
   // Did we start the match at the start of the string at all?
-  __ cmpb(Operand(rbp, kStartIndex), Immediate(0));
+  __ cmpl(Operand(rbp, kStartIndex), Immediate(0));
   BranchOrBacktrack(not_equal, on_not_at_start);
   // If we did, are we still at the start of the input?
   __ lea(rax, Operand(rsi, rdi, times_1, 0));
diff --git a/deps/v8/test/mjsunit/regress/regress-1748.js b/deps/v8/test/mjsunit/regress/regress-1748.js
new file mode 100644
index 0000000000..e287e55496
--- /dev/null
+++ b/deps/v8/test/mjsunit/regress/regress-1748.js
@@ -0,0 +1,35 @@
+// Copyright 2011 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+//       notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+//       copyright notice, this list of conditions and the following
+//       disclaimer in the documentation and/or other materials provided
+//       with the distribution.
+//     * Neither the name of Google Inc. nor the names of its
+//       contributors may be used to endorse or promote products derived
+//       from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Test that /^/ only matches at beginning of string.
+// Bug in x64 caused it to match when executing the RegExp on a part
+// of a string that starts at a multiplum of 256.
+
+var str = Array(10000).join("X");
+str.replace(/^|X/g, function(m, i, s) {
+  if (i > 0) assertEquals("X", m, "at position 0x" + i.toString(16));
+});
\ No newline at end of file