Simplify BlockEntryInstr::DiscoverBlocks a bit.

vm/intermediate_language.cc

 // 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.
 
 #include "vm/intermediate_language.h"
 
 #include "vm/bit_vector.h"
 #include "vm/dart_entry.h"
 #include "vm/flow_graph_builder.h"
 #include "vm/flow_graph_compiler.h"
@@ skipping 543 matching lines @@
       (variable_count == 0) ? NULL : new BitVector(variable_count);
   assigned_vars->Add(vars);
   // The preorder, parent, and assigned_vars arrays are all indexed by
   // preorder block number, so they should stay in lockstep.
   ASSERT(preorder->length() == parent->length());
   ASSERT(preorder->length() == assigned_vars->length());
 
   // 5. Iterate straight-line successors until a branch instruction or
   // another basic block entry instruction, and visit that instruction.
   ASSERT(next() != NULL);
+  ASSERT(!next()->IsBlockEntry());
   Instruction* next_instr = next();
-  if (next_instr->IsBlockEntry()) {
-    set_last_instruction(this);
-  } else {
-    while ((next_instr != NULL) &&
-           !next_instr->IsBlockEntry() &&
-           !next_instr->IsBranch()) {
-      if (vars != NULL) {
-        next_instr->RecordAssignedVars(vars, fixed_parameter_count);
-      }
-      set_last_instruction(next_instr);
-      GotoInstr* goto_instr = next_instr->AsGoto();
-      next_instr =
-          (goto_instr != NULL) ? goto_instr->successor() : next_instr->next();
+  while ((next_instr != NULL) &&
+         !next_instr->IsBlockEntry() &&
+         !next_instr->IsBranch()) {
+    if (vars != NULL) {
+      next_instr->RecordAssignedVars(vars, fixed_parameter_count);
     }
+    set_last_instruction(next_instr);
+    GotoInstr* goto_instr = next_instr->AsGoto();
+    next_instr =
+        (goto_instr != NULL) ? goto_instr->successor() : next_instr->next();
   }
   if (next_instr != NULL) {
     next_instr->DiscoverBlocks(this, preorder, postorder,
                                parent, assigned_vars,
                                variable_count, fixed_parameter_count);
   }
 
   // 6. Assign postorder number and add the block entry to the list.
   set_postorder_number(postorder->length());
   postorder->Add(this);
@@ skipping 799 matching lines @@
   if (compiler->is_ssa()) {
     ASSERT(locs()->in(0).IsRegister());
     __ PushRegister(locs()->in(0).reg());
   }
 }
 
 
 #undef __
 
 }  // namespace dart