Fixes to RegExp-IA32.

src/regexp-macro-assembler-ia32.cc

 // Copyright 2008 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
@@ skipping 174 matching lines @@
   } else {
     memcpy(constant_buffer.location(),
            str.start(),
            str.length() * sizeof(uc16));
   }
 
   __ mov(eax, edi);
   __ mov(ebx, esi);
   __ lea(edi, Operand(esi, edi, times_1, byte_offset));
   LoadConstantBufferAddress(esi, &constant_buffer);
-  __ mov(ecx, str.length());
-  if (mode_ == ASCII) {
+  if ((str.length() * char_size()) & 0x03 == 0) {
+    // String content is a multiple of sizoef(uint32_t).
+    __ mov(ecx, str.length() * char_size() >> 2);
+    __ rep_cmpsl();

[Erik Corry, 2008/11/27 13:04:36]

Premature optimization!
Did you get rid of ASCII mode?

+  } else {
+    __ mov(ecx, str.length() * char_size());
     __ rep_cmpsb();
-  } else {
-    ASSERT(mode_ == UC16);
-    __ rep_cmpsw();
   }
   __ mov(esi, ebx);
   __ mov(edi, eax);
   BranchOrBacktrack(not_equal, on_failure);
 }
 
 
 void RegExpMacroAssemblerIA32::CheckCurrentPosition(int register_index,
                                                     Label* on_equal) {
   __ cmp(edi, register_location(register_index));
@@ skipping 12 matching lines @@
   Label fallthrough;
   __ mov(eax, register_location(start_reg));
   __ mov(ecx, register_location(start_reg + 1));
   __ sub(ecx, Operand(eax));  // Length to check.
   __ j(equal, &fallthrough);  // Covers the case where it's not bound (-1,-1).
   __ mov(ebx, Operand(edi));
   __ push(esi);
   __ add(edi, Operand(esi));
   __ add(esi, Operand(eax));
   if (mode_ == ASCII) {
     __ rep_cmpsb();

[Erik Corry, 2008/11/27 13:04:36]

One of the if bodies is a suffix of the other.  That suggests a simplification!

   } else {
-    __ rep_cmpsw();
+    __ add(ecx, Operand(ecx));
+    __ rep_cmpsb();
   }
   __ pop(esi);
   __ mov(edi, Operand(ebx));
   BranchOrBacktrack(not_equal, on_no_match);
   __ bind(&fallthrough);
 }
 
 
 void RegExpMacroAssemblerIA32::CheckNotCharacter(uc16 c, Label* on_not_equal) {
   __ cmp(edx, c);
@@ skipping 380 matching lines @@
 
 
 void RegExpMacroAssemblerIA32::LoadConstantBufferAddress(Register reg,
                                                          ArraySlice* buffer) {
   __ mov(reg, buffer->array());
   __ add(Operand(reg), Immediate(buffer->base_offset()));
 }
 
 #undef __
 }}  // namespace v8::internal