Revert of Internalize strings in-place

src/ppc/code-stubs-ppc.cc

Index: src/ppc/code-stubs-ppc.cc
diff --git a/src/ppc/code-stubs-ppc.cc b/src/ppc/code-stubs-ppc.cc
index 3b3d9dcb49fbfbe1288bcd4c2d4e160d48692aee..9b84f5c0a62f9cebd4cbbfd7f79b3c5f359021d0 100644
--- a/src/ppc/code-stubs-ppc.cc
+++ b/src/ppc/code-stubs-ppc.cc
@@ -1374,7 +1374,7 @@
   // (6) External string.  Make it, offset-wise, look like a sequential string.
   //     Go to (4).
   // (7) Short external string or not a string?  If yes, bail out to runtime.
-  // (8) Sliced or thin string.  Replace subject with parent.  Go to (1).
+  // (8) Sliced string.  Replace subject with parent.  Go to (1).
 
   Label seq_string /* 4 */, external_string /* 6 */, check_underlying /* 1 */,
       not_seq_nor_cons /* 5 */, not_long_external /* 7 */;
@@ -1395,7 +1395,6 @@
   // (2) Sequential or cons? If not, go to (5).
   STATIC_ASSERT(kConsStringTag < kExternalStringTag);
   STATIC_ASSERT(kSlicedStringTag > kExternalStringTag);
-  STATIC_ASSERT(kThinStringTag > kExternalStringTag);
   STATIC_ASSERT(kIsNotStringMask > kExternalStringTag);
   STATIC_ASSERT(kShortExternalStringTag > kExternalStringTag);
   STATIC_ASSERT(kExternalStringTag < 0xffffu);
@@ -1672,18 +1671,11 @@
   __ andi(r0, r4, Operand(kIsNotStringMask | kShortExternalStringMask));
   __ bne(&runtime, cr0);
 
-  // (8) Sliced or thin string.  Replace subject with parent.  Go to (4).
-  Label thin_string;
-  __ cmpi(r4, Operand(kThinStringTag));
-  __ beq(&thin_string);
+  // (8) Sliced string.  Replace subject with parent.  Go to (4).
   // Load offset into r11 and replace subject string with parent.
   __ LoadP(r11, FieldMemOperand(subject, SlicedString::kOffsetOffset));
   __ SmiUntag(r11);
   __ LoadP(subject, FieldMemOperand(subject, SlicedString::kParentOffset));
-  __ b(&check_underlying);  // Go to (4).
-
-  __ bind(&thin_string);
-  __ LoadP(subject, FieldMemOperand(subject, ThinString::kActualOffset));
   __ b(&check_underlying);  // Go to (4).
 #endif  // V8_INTERPRETED_REGEXP
 }