Add Uint32 representation

runtime/vm/compiler.cc

Index: runtime/vm/compiler.cc
diff --git a/runtime/vm/compiler.cc b/runtime/vm/compiler.cc
index 9c2822a0b67e04a98206cc8fa9cf470f112b7fa2..8417b9a2980e7f3e0edc9f4b64d113857ff873d5 100644
--- a/runtime/vm/compiler.cc
+++ b/runtime/vm/compiler.cc
@@ -453,6 +453,10 @@ static bool CompileParsedFunctionHelper(ParsedFunction* parsed_function,
           // making some phis smi.
           optimizer.InferIntRanges();
           DEBUG_ASSERT(flow_graph->VerifyUseLists());
+
+          // Select integer instructions based on range analysis result.
+          optimizer.SelectIntegerInstructions();

[Florian Schneider, 2014/07/08 12:24:28]

I think this phase should be run as part of RangeAnalysis by moving it to
RangeAnalysis::Analyze, so that the constraints inserted for branches are still
present.

[Cutch, 2014/07/09 17:48:25]

Are you suggesting that we do a range analysis pass *after* replacing Mint
operations with Uint32 operations? Please explain more what you're thinking.

[Florian Schneider, 2014/07/10 13:05:05]

No, your pass runs after range analysis, but before
RangeAnalysis::RemoveConstraints. This way you get better constraints for
branches. e.g.

if (a > 0 && a < 16) {
  // a has range [0..15] here.
}

[Cutch, 2014/07/10 17:12:53]

I've added a TODO for a follow up CL.

+          DEBUG_ASSERT(flow_graph->VerifyUseLists());
         }
 
         if (FLAG_constant_propagation) {