Regexp: Improve the speed that we scan for an initial point where a non-anchored

src/x64/regexp-macro-assembler-x64.cc

Index: src/x64/regexp-macro-assembler-x64.cc
===================================================================
--- src/x64/regexp-macro-assembler-x64.cc	(revision 11190)
+++ src/x64/regexp-macro-assembler-x64.cc	(working copy)
@@ -542,9 +542,13 @@
 void RegExpMacroAssemblerX64::CheckCharacterAfterAnd(uint32_t c,
                                                      uint32_t mask,
                                                      Label* on_equal) {
-  __ movl(rax, current_character());
-  __ and_(rax, Immediate(mask));
-  __ cmpl(rax, Immediate(c));
+  if (c == 0) {
+    __ testl(current_character(), Immediate(mask));
+  } else {
+    __ movl(rax, Immediate(mask));
+    __ and_(rax, current_character());
+    __ cmpl(rax, Immediate(c));
+  }
   BranchOrBacktrack(equal, on_equal);
 }
 
@@ -552,9 +556,13 @@
 void RegExpMacroAssemblerX64::CheckNotCharacterAfterAnd(uint32_t c,
                                                         uint32_t mask,
                                                         Label* on_not_equal) {
-  __ movl(rax, current_character());
-  __ and_(rax, Immediate(mask));
-  __ cmpl(rax, Immediate(c));
+  if (c == 0) {
+    __ testl(current_character(), Immediate(mask));
+  } else {
+    __ movl(rax, Immediate(mask));
+    __ and_(rax, current_character());
+    __ cmpl(rax, Immediate(c));
+  }
   BranchOrBacktrack(not_equal, on_not_equal);
 }