Merge libv1.

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

Index: sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart b/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
index e27f697219c86f8b502a192a324313fd6a712c9c..26f990dbb28a1798b1bb32c86187bba6635fc3a2 100644
--- a/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
+++ b/sdk/lib/_internal/compiler/implementation/ssa/optimize.dart
@@ -398,7 +398,6 @@ class SsaConstantFolder extends HBaseVisitor implements OptimizationPhase {
     HInstruction right = node.right;
     HType leftType = types[left];
     HType rightType = types[right];
-    assert(!leftType.isConflicting() && !rightType.isConflicting());
 
     // We don't optimize on numbers to preserve the runtime semantics.
     if (!(left.isNumberOrNull(types) && right.isNumberOrNull(types)) &&
@@ -752,6 +751,7 @@ class SsaDeadCodeEliminator extends HGraphVisitor implements OptimizationPhase {
            && instruction is !HInvokeDynamicGetter
            && instruction is !HCheck
            && instruction is !HTypeGuard
+           && instruction is !HParameterValue
            && !instruction.isControlFlow();
   }