Support non-deoptimizing version of UnboxInt32 for integer definitions.

runtime/vm/intermediate_language_mips.cc

Index: runtime/vm/intermediate_language_mips.cc
diff --git a/runtime/vm/intermediate_language_mips.cc b/runtime/vm/intermediate_language_mips.cc
index 1257aed0d757a0f6f3f6ee2cbe1edabf10ec3c26..8945874eb895a59b911919545217538e6c4455f7 100644
--- a/runtime/vm/intermediate_language_mips.cc
+++ b/runtime/vm/intermediate_language_mips.cc
@@ -3347,6 +3347,13 @@ void UnboxInteger32Instr::EmitNativeCode(FlowGraphCompiler* compiler) {
     __ SmiUntag(out, value);
   } else if (value_cid == kMintCid) {
     LoadInt32FromMint(compiler, value, out, out_of_range);
+  } else if (!CanDeoptimize()) {
+    Label done;
+    __ SmiUntag(out, value);
+    __ andi(CMPRES1, value, Immediate(kSmiTagMask));
+    __ beq(CMPRES1, ZR, &done);
+    LoadInt32FromMint(compiler, value, out, out_of_range);

[Florian Schneider, 2014/12/02 13:12:04]

Same comment as on ARM.

[Vyacheslav Egorov (Google), 2014/12/02 13:15:58]

Done.

+    __ Bind(&done);
   } else {
     Label done;
     __ SmiUntag(out, value);