Make kAsciiDataHintTag have correct semantics for all both 1 and 2 byte string types.

src/x64/macro-assembler-x64.cc

Index: src/x64/macro-assembler-x64.cc
diff --git a/src/x64/macro-assembler-x64.cc b/src/x64/macro-assembler-x64.cc
index 962c2e8b45e0067e6b81c9601ca2d64b5c1fa5a8..3fea033fe0c128d2e291e286a001893299998125 100644
--- a/src/x64/macro-assembler-x64.cc
+++ b/src/x64/macro-assembler-x64.cc
@@ -2201,16 +2201,19 @@ void MacroAssembler::JumpIfNotBothSequentialAsciiStrings(
   // Check that both are flat ASCII strings.
   ASSERT(kNotStringTag != 0);
   const int kFlatAsciiStringMask =
-      kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
+      kIsNotStringMask | kStringEncodingMask | kAsciiDataHintMask |
+      kStringRepresentationMask;
   const int kFlatAsciiStringTag = ASCII_STRING_TYPE;
 
   andl(scratch1, Immediate(kFlatAsciiStringMask));
   andl(scratch2, Immediate(kFlatAsciiStringMask));
   // Interleave the bits to check both scratch1 and scratch2 in one test.
-  ASSERT_EQ(0, kFlatAsciiStringMask & (kFlatAsciiStringMask << 3));
-  lea(scratch1, Operand(scratch1, scratch2, times_8, 0));
+  ASSERT_EQ(0, kFlatAsciiStringMask & (kFlatAsciiStringMask << 8));
+  ASSERT_EQ(ASCII_STRING_TYPE, ASCII_STRING_TYPE & kFlatAsciiStringMask);
+  shl(scratch1, Immediate(8));
+  orl(scratch1, scratch2);
   cmpl(scratch1,
-       Immediate(kFlatAsciiStringTag + (kFlatAsciiStringTag << 3)));
+       Immediate(kFlatAsciiStringTag + (kFlatAsciiStringTag << 8)));
   j(not_equal, on_fail, near_jump);
 }
 
@@ -2246,17 +2249,19 @@ void MacroAssembler::JumpIfBothInstanceTypesAreNotSequentialAscii(
 
   // Check that both are flat ASCII strings.
   ASSERT(kNotStringTag != 0);
-  const int kFlatAsciiStringMask =
-      kIsNotStringMask | kStringRepresentationMask | kStringEncodingMask;
+  const int kFlatAsciiStringMask = kIsNotStringMask | kStringRepresentationMask
+          | kStringEncodingMask | kAsciiDataHintTag;
   const int kFlatAsciiStringTag = ASCII_STRING_TYPE;
 
   andl(scratch1, Immediate(kFlatAsciiStringMask));
   andl(scratch2, Immediate(kFlatAsciiStringMask));
   // Interleave the bits to check both scratch1 and scratch2 in one test.
-  ASSERT_EQ(0, kFlatAsciiStringMask & (kFlatAsciiStringMask << 3));
-  lea(scratch1, Operand(scratch1, scratch2, times_8, 0));
+  ASSERT_EQ(0, kFlatAsciiStringMask & (kFlatAsciiStringMask << 8));
+  ASSERT_EQ(ASCII_STRING_TYPE, ASCII_STRING_TYPE & kFlatAsciiStringMask);
+  shl(scratch1, Immediate(8));
+  orl(scratch1, scratch2);
   cmpl(scratch1,
-       Immediate(kFlatAsciiStringTag + (kFlatAsciiStringTag << 3)));
+       Immediate(kFlatAsciiStringTag + (kFlatAsciiStringTag << 8)));
   j(not_equal, on_fail, near_jump);
 }