MIPS: Cleanup: use JumpIf[Not]Smi() whenever we can

src/mips/full-codegen-mips.cc

Index: src/mips/full-codegen-mips.cc
diff --git a/src/mips/full-codegen-mips.cc b/src/mips/full-codegen-mips.cc
index cde46b0eb61fc74cc155d4c4cd1b897ed5b444a0..cbfe8a46a26e18199bfec017c59331a1a6a74fda 100644
--- a/src/mips/full-codegen-mips.cc
+++ b/src/mips/full-codegen-mips.cc
@@ -3367,8 +3367,7 @@ void FullCodeGenerator::EmitIsRegExpEquivalent(ZoneList<Expression*>* args) {
   __ Branch(&ok, eq, left, Operand(right));
   // Fail if either is a non-HeapObject.
   __ And(tmp, left, Operand(right));
-  __ And(at, tmp, Operand(kSmiTagMask));
-  __ Branch(&fail, eq, at, Operand(zero_reg));
+  __ JumpIfSmi(tmp, &fail);
   __ lw(tmp, FieldMemOperand(left, HeapObject::kMapOffset));
   __ lbu(tmp2, FieldMemOperand(tmp, Map::kInstanceTypeOffset));
   __ Branch(&fail, ne, tmp2, Operand(JS_REGEXP_TYPE));
@@ -4233,8 +4232,7 @@ void FullCodeGenerator::EmitLiteralCompareNil(CompareOperation* expr,
     __ Branch(if_true, eq, a0, Operand(a1));
     __ LoadRoot(a1, other_nil_value);
     __ Branch(if_true, eq, a0, Operand(a1));
-    __ And(at, a0, Operand(kSmiTagMask));
-    __ Branch(if_false, eq, at, Operand(zero_reg));
+    __ JumpIfSmi(a0, if_false);
     // It can be an undetectable object.
     __ lw(a1, FieldMemOperand(a0, HeapObject::kMapOffset));
     __ lbu(a1, FieldMemOperand(a1, Map::kBitFieldOffset));