MIPS: Improve code generation for bounds checks.

src/mips/macro-assembler-mips.cc

Index: src/mips/macro-assembler-mips.cc
diff --git a/src/mips/macro-assembler-mips.cc b/src/mips/macro-assembler-mips.cc
index 1187c41d29d73baa902eef107dbb18f46c607824..e345666e9c1d28fff24fd75afc7ac2f8ff35d4a2 100644
--- a/src/mips/macro-assembler-mips.cc
+++ b/src/mips/macro-assembler-mips.cc
@@ -2091,7 +2091,7 @@ void MacroAssembler::BranchShort(Label* L, Condition cond, Register rs,
       case Uless_equal:
         if (rt.imm32_ == 0) {
           offset = shifted_branch_offset(L, false);
-          b(offset);
+          beq(rs, zero_reg, offset);
         } else {
           ASSERT(!scratch.is(rs));
           r2 = scratch;