MIPS: Regexp: Improve the speed that we scan for an initial point

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

Index: src/mips/regexp-macro-assembler-mips.cc
diff --git a/src/mips/regexp-macro-assembler-mips.cc b/src/mips/regexp-macro-assembler-mips.cc
index dde4a65a9ead81d51a3078317f69b88c09578837..225d4d02187d5fce89ac74f5e772231c5ff92b90 100644
--- a/src/mips/regexp-macro-assembler-mips.cc
+++ b/src/mips/regexp-macro-assembler-mips.cc
@@ -461,7 +461,8 @@ void RegExpMacroAssemblerMIPS::CheckCharacterAfterAnd(uint32_t c,
                                                      uint32_t mask,
                                                      Label* on_equal) {
   __ And(a0, current_character(), Operand(mask));
-  BranchOrBacktrack(on_equal, eq, a0, Operand(c));
+  Operand rhs = (c == 0) ? Operand(zero_reg) : Operand(c);
+  BranchOrBacktrack(on_equal, eq, a0, rhs);
 }
 
 
@@ -469,7 +470,8 @@ void RegExpMacroAssemblerMIPS::CheckNotCharacterAfterAnd(uint32_t c,
                                                         uint32_t mask,
                                                         Label* on_not_equal) {
   __ And(a0, current_character(), Operand(mask));
-  BranchOrBacktrack(on_not_equal, ne, a0, Operand(c));
+  Operand rhs = (c == 0) ? Operand(zero_reg) : Operand(c);
+  BranchOrBacktrack(on_not_equal, ne, a0, rhs);
 }