Validate that all instructions dominate their inputs. And fix a bug where that did not happen.

lib/compiler/implementation/ssa/nodes.dart

Index: lib/compiler/implementation/ssa/nodes.dart
===================================================================
--- lib/compiler/implementation/ssa/nodes.dart	(revision 8084)
+++ lib/compiler/implementation/ssa/nodes.dart	(working copy)
@@ -661,6 +661,14 @@
     }
   }
 
+  void forEachInstruction(void f(HInstruction instruction)) {
+    HInstruction current = first;
+    while (current !== null) {

[Lasse Reichstein Nielsen, 2012/05/30 09:35:14]

A block must have a non-null first instruction (right?).
So you could make this a do-while instead and save one comparison :)

[ngeoffray, 2012/05/30 10:19:07]

It might be safer to keep it as-is in case one use forEachInstruction while
building (and the block does not have any instruction).

+      f(current);
+      current = current.next;
+    }
+  }
+
   bool isValid() {
     assert(isClosed());
     HValidator validator = new HValidator();
@@ -1664,6 +1672,7 @@
 
 class HTry extends HControlFlow {
   HParameterValue exception;
+  HBasicBlock catchBlock;
   HBasicBlock finallyBlock;
   HTry() : super(const <HInstruction>[]);
   toString() => 'try';