When doing SSA type propagation, refine the receiver after a call.

sdk/lib/_internal/compiler/implementation/ssa/optimize.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 part of ssa;
 
 abstract class OptimizationPhase {
   String get name;
   void visitGraph(HGraph graph);
 }
@@ skipping 21 matching lines @@
   void optimize(CodegenWorkItem work, HGraph graph) {
     ConstantSystem constantSystem = compiler.backend.constantSystem;
     JavaScriptItemCompilationContext context = work.compilationContext;
     measure(() {
       SsaDeadCodeEliminator dce;
       List<OptimizationPhase> phases = <OptimizationPhase>[
           // Run trivial instruction simplification first to optimize
           // some patterns useful for type conversion.
           new SsaInstructionSimplifier(constantSystem, backend, work),
           new SsaTypeConversionInserter(compiler),
+          new SsaRedundantPhiEliminator(),
+          new SsaDeadPhiEliminator(),
           new SsaTypePropagator(compiler),
           // After type propagation, more instructions can be
           // simplified.
           new SsaInstructionSimplifier(constantSystem, backend, work),
           new SsaCheckInserter(backend, work, context.boundsChecked),
-          new SsaRedundantPhiEliminator(),
-          new SsaDeadPhiEliminator(),
           new SsaInstructionSimplifier(constantSystem, backend, work),
           new SsaCheckInserter(backend, work, context.boundsChecked),
           new SsaTypePropagator(compiler),
           // Run a dead code eliminator before LICM because dead
           // interceptors are often in the way of LICM'able instructions.
           new SsaDeadCodeEliminator(compiler),
           new SsaGlobalValueNumberer(compiler),
+          // After GVN, some instructions might need their type to be
+          // updated because they now have different inputs.
+          new SsaTypePropagator(compiler),
           new SsaCodeMotion(),
           new SsaValueRangeAnalyzer(compiler, constantSystem, work),
           // Previous optimizations may have generated new
           // opportunities for instruction simplification.
           new SsaInstructionSimplifier(constantSystem, backend, work),
           new SsaCheckInserter(backend, work, context.boundsChecked),
           new SsaSimplifyInterceptors(compiler, constantSystem, work),
           dce = new SsaDeadCodeEliminator(compiler)];
       runPhases(graph, phases);
       if (!dce.eliminatedSideEffects) return;
@@ skipping 1448 matching lines @@
       // that knows it is not of a specific Type.
     }
 
     for (HIf ifUser in notIfUsers) {
       changeUsesDominatedBy(ifUser.elseBlock, input, convertedType);
       // TODO(ngeoffray): Also change uses for the then block on a HType
       // that knows it is not of a specific Type.
     }
   }
 }