Make sure the merge block after a try/catch has its dominator the block that contains HTry. This wa…

frog/leg/ssa/builder.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.
 
 class Interceptors {
   Compiler compiler;
   Interceptors(Compiler this.compiler);
 
   SourceString mapOperatorToMethodName(Operator op) {
     String name = op.source.stringValue;
@@ skipping 1991 matching lines @@
     compiler.unimplemented('SsaBuilder.visitSwitchStatement', node: node);
   }
 
   visitTryStatement(TryStatement node) {
     work.allowSpeculativeOptimization = false;
     assert(!work.isBailoutVersion());
     HBasicBlock enterBlock = graph.addNewBlock();
     close(new HGoto()).addSuccessor(enterBlock);
     open(enterBlock);
     HTry tryInstruction = new HTry();
-    close(tryInstruction);
+    List<HBasicBlock> blocks = <HBasicBlock>[];
+    blocks.add(close(tryInstruction));
 
     HBasicBlock tryBody = graph.addNewBlock();
     enterBlock.addSuccessor(tryBody);
     open(tryBody);
     visit(node.tryBlock);
-    List<HBasicBlock> blocks = <HBasicBlock>[];
     if (!isAborted()) blocks.add(close(new HGoto()));
 
     if (!node.catchBlocks.isEmpty()) {
       HBasicBlock block = graph.addNewBlock();
       enterBlock.addSuccessor(block);
       open(block);
       // Note that the name of this element is irrelevant.
       Element element = new Element(
           const SourceString('exception'), ElementKind.PARAMETER, work.element);
       HParameterValue exception = new HParameterValue(element);
@@ skipping 43 matching lines @@
 
     if (node.finallyBlock != null) {
       HBasicBlock finallyBlock = graph.addNewBlock();
       enterBlock.addSuccessor(finallyBlock);
       open(finallyBlock);
       visit(node.finallyBlock);
       if (!isAborted()) blocks.add(close(new HGoto()));
       tryInstruction.finallyBlock = finallyBlock;
     }
 
-    // If no block is going to an exit block, the Dart code after the
-    // try is dead code.
-    if (!blocks.isEmpty()) {
-      HBasicBlock exitBlock = graph.addNewBlock();
+    HBasicBlock exitBlock = graph.addNewBlock();
 
-      for (HBasicBlock block in blocks) {
-        block.addSuccessor(exitBlock);
-      }
+    for (HBasicBlock block in blocks) {
+      block.addSuccessor(exitBlock);
+    }
 
-      open(exitBlock);
-    }
+    open(exitBlock);
   }
 
   visitScriptTag(ScriptTag node) {
     compiler.unimplemented('SsaBuilder.visitScriptTag', node: node);
   }
 
   visitCatchBlock(CatchBlock node) {
     visit(node.block);
   }
 
   visitTypedef(Typedef node) {
     compiler.unimplemented('SsaBuilder.visitTypedef', node: node);
   }
 }