remove HIf.hasElse.

An HIf always has an else. It might be empty, though.

Review URL: https://chromiumcodereview.appspot.com//10693059

git-svn-id: https://dart.googlecode.com/svn/branches/bleeding_edge/dart@9285 260f80e4-7a28-3924-810f-c04153c831b5

lib/compiler/implementation/ssa/bailout.dart

@@ -454,10 +454,8 @@ class SsaBailoutPropagator extends HBaseVisitor {
     HIfBlockInformation info = instruction.blockInformation.body;
     visitStatements(info.thenGraph);
     preVisitedBlocks++;
-    if (instruction.hasElse) {
-      visitStatements(info.elseGraph);
-      preVisitedBlocks++;
-    }
+    visitStatements(info.elseGraph);
+    preVisitedBlocks++;
 
     HBasicBlock joinBlock = instruction.joinBlock;
     if (joinBlock !== null

lib/compiler/implementation/ssa/builder.dart

@@ -1578,7 +1578,7 @@ class SsaBuilder extends ResolvedVisitor implements Visitor {
     SubExpression conditionGraph =
         new SubExpression(conditionStartBlock, lastOpenedBlock);
     HInstruction condition = popBoolified();
-    HIf branch = new HIf(condition, true);
+    HIf branch = new HIf(condition);
     HBasicBlock conditionBlock = close(branch);
 
     LocalsHandler savedLocals = new LocalsHandler.from(localsHandler);

lib/compiler/implementation/ssa/codegen.dart

@@ -1703,7 +1703,7 @@ class SsaCodeGenerator implements HVisitor, HBlockInformationVisitor {
     // Depending on how the then/else branches terminate
     // (e.g., return/throw/break) there can be any number of these.
     List<HBasicBlock> dominated = node.block.dominatedBlocks;
-    for (int i = node.hasElse ? 2 : 1; i < dominated.length; i++) {
+    for (int i = 2; i < dominated.length; i++) {
       visitBasicBlock(dominated[i]);
     }
   }
@@ -3048,15 +3048,15 @@ class SsaUnoptimizedCodeGenerator extends SsaCodeGenerator {
     HStatementInformation thenGraph = info.thenGraph;
     HStatementInformation elseGraph = info.elseGraph;
     bool thenHasGuards = thenGraph.start.hasGuards();
-    bool elseHasGuards = node.hasElse && elseGraph.start.hasGuards();
+    bool elseHasGuards = elseGraph.start.hasGuards();
     bool hasGuards = thenHasGuards || elseHasGuards;
     if (!hasGuards) return super.generateIf(node, info);
 
     int elseKind = analyzeGraphForCodegen(elseGraph);
-    bool emptyElse = !node.hasElse || elseKind == SsaCodeGenerator.EMPTY;
+    bool emptyElse = elseKind == SsaCodeGenerator.EMPTY;
 
     startBailoutCase(thenGraph.start.guards,
-        node.hasElse ? elseGraph.start.guards : const <HTypeGuard>[]);
+        emptyElse ? const <HTypeGuard>[] : elseGraph.start.guards);
 
     addIndented('if (');
     int precedence = JSPrecedence.EXPRESSION_PRECEDENCE;

lib/compiler/implementation/ssa/nodes.dart

@@ -1748,9 +1748,8 @@ class HTry extends HControlFlow {
 }
 
 class HIf extends HConditionalBranch {
-  bool hasElse;
   HBlockFlow blockInformation = null;
-  HIf(HInstruction condition, this.hasElse) : super(<HInstruction>[condition]);
+  HIf(HInstruction condition) : super(<HInstruction>[condition]);
   toString() => 'if';
   accept(HVisitor visitor) => visitor.visitIf(this);
 
@@ -1760,12 +1759,8 @@ class HIf extends HConditionalBranch {
   }
 
   HBasicBlock get elseBlock() {
-    if (hasElse) {
-      assert(block.dominatedBlocks[1] === block.successors[1]);
-      return block.successors[1];
-    } else {
-      return null;
-    }
+    assert(block.dominatedBlocks[1] === block.successors[1]);
+    return block.successors[1];
   }
 
   HBasicBlock get joinBlock() => blockInformation.continuation;

lib/compiler/implementation/ssa/optimize.dart

@@ -1168,15 +1168,7 @@ class SsaTypeConversionInserter extends HBaseVisitor
     }
 
     for (HIf ifUser in notIfUsers) {
-      if (ifUser.hasElse) {
-        changeUsesDominatedBy(ifUser.elseBlock, input, convertedType);
-      } else if (ifUser.joinBlock.predecessors.length == 1) {
-        // If the join block has only one predecessor, then we know
-        // the if block terminates. So any use of the instruction
-        // after the join block should be changed to the new
-        // instruction.
-        changeUsesDominatedBy(ifUser.joinBlock, input, convertedType);
-      }
+      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.
     }