6 files changed, 55 insertions, 1 deletions

diff --git a/src/qml/compiler/qv4isel_masm.cpp b/src/qml/compiler/qv4isel_masm.cpp
index 1146c08d6c..98558bf9bc 100644
--- a/src/qml/compiler/qv4isel_masm.cpp
+++ b/src/qml/compiler/qv4isel_masm.cpp
@@ -667,6 +667,8 @@ void InstructionSelection::run(int functionIndex)
         ConvertTemps().toStackSlots(_function);
     }
     V4IR::Optimizer::showMeTheCode(_function);
+    QSet<V4IR::Jump *> removableJumps = opt.calculateOptionalJumps();
+    qSwap(_removableJumps, removableJumps);
 
     Assembler* oldAssembler = _as;
     _as = new Assembler(this, _function, executableAllocator, 6); // 6 == max argc for calls to built-ins with an argument array
@@ -715,6 +717,7 @@ void InstructionSelection::run(int functionIndex)
     qSwap(_reentryBlocks, reentryBlocks);
     delete _as;
     _as = oldAssembler;
+    qSwap(_removableJumps, removableJumps);
 }
 
 void *InstructionSelection::addConstantTable(QVector<Primitive> *values)
@@ -1675,7 +1678,8 @@ void InstructionSelection::constructValue(V4IR::Temp *value, V4IR::ExprList *arg
 
 void InstructionSelection::visitJump(V4IR::Jump *s)
 {
-    _as->jumpToBlock(_block, s->target);
+    if (!_removableJumps.contains(s))
+        _as->jumpToBlock(_block, s->target);
 }
 
 void InstructionSelection::visitCJump(V4IR::CJump *s)
diff --git a/src/qml/compiler/qv4isel_masm_p.h b/src/qml/compiler/qv4isel_masm_p.h
index 013c2ef8ed..1a8df9a833 100644
--- a/src/qml/compiler/qv4isel_masm_p.h
+++ b/src/qml/compiler/qv4isel_masm_p.h
@@ -1550,6 +1550,7 @@ private:
 
     V4IR::BasicBlock *_block;
     V4IR::Function* _function;
+    QSet<V4IR::Jump *> _removableJumps;
     Assembler* _as;
     QSet<V4IR::BasicBlock*> _reentryBlocks;
 
diff --git a/src/qml/compiler/qv4isel_moth.cpp b/src/qml/compiler/qv4isel_moth.cpp
index 7c999edb59..0b9473b1d3 100644
--- a/src/qml/compiler/qv4isel_moth.cpp
+++ b/src/qml/compiler/qv4isel_moth.cpp
@@ -252,7 +252,11 @@ void InstructionSelection::run(int functionIndex)
         stackSlotAllocator = new StackSlotAllocator(opt.lifeRanges(), _function->tempCount);
         opt.convertOutOfSSA();
     }
+
     qSwap(_stackSlotAllocator, stackSlotAllocator);
+    QSet<V4IR::Jump *> removableJumps = opt.calculateOptionalJumps();
+    qSwap(_removableJumps, removableJumps);
+
     V4IR::Stmt *cs = 0;
     qSwap(_currentStatement, cs);
 
@@ -289,6 +293,7 @@ void InstructionSelection::run(int functionIndex)
     codeRefs.insert(_function, squeezeCode());
 
     qSwap(_currentStatement, cs);
+    qSwap(_removableJumps, removableJumps);
     qSwap(_stackSlotAllocator, stackSlotAllocator);
     delete stackSlotAllocator;
     qSwap(_function, function);
@@ -629,6 +634,8 @@ void InstructionSelection::visitJump(V4IR::Jump *s)
 {
     if (s->target == _nextBlock)
         return;
+    if (_removableJumps.contains(s))
+        return;
 
     Instruction::Jump jump;
     jump.offset = 0;
diff --git a/src/qml/compiler/qv4isel_moth_p.h b/src/qml/compiler/qv4isel_moth_p.h
index ca03c5fa30..725dd264aa 100644
--- a/src/qml/compiler/qv4isel_moth_p.h
+++ b/src/qml/compiler/qv4isel_moth_p.h
@@ -175,6 +175,7 @@ private:
     uchar *_codeEnd;
 
     StackSlotAllocator *_stackSlotAllocator;
+    QSet<V4IR::Jump *> _removableJumps;
     V4IR::Stmt *_currentStatement;
 
     CompilationUnit *compilationUnit;
diff --git a/src/qml/compiler/qv4ssa.cpp b/src/qml/compiler/qv4ssa.cpp
index 6ad9a5731f..c41c9cfe80 100644
--- a/src/qml/compiler/qv4ssa.cpp
+++ b/src/qml/compiler/qv4ssa.cpp
@@ -2976,6 +2976,45 @@ QVector<LifeTimeInterval> Optimizer::lifeRanges() const
     return lifeRanges.ranges();
 }
 
+QSet<Jump *> Optimizer::calculateOptionalJumps()
+{
+    QSet<Jump *> optional;
+    QSet<BasicBlock *> reachableWithoutJump;
+
+    const int maxSize = function->basicBlocks.size();
+    optional.reserve(maxSize);
+    reachableWithoutJump.reserve(maxSize);
+
+    for (int i = function->basicBlocks.size() - 1; i >= 0; --i) {
+        BasicBlock *bb = function->basicBlocks[i];
+
+        if (Jump *jump = bb->statements.last()->asJump()) {
+            if (reachableWithoutJump.contains(jump->target)) {
+                if (bb->statements.size() > 1)
+                    reachableWithoutJump.clear();
+                optional.insert(jump);
+                reachableWithoutJump.insert(bb);
+                continue;
+            }
+        }
+
+        reachableWithoutJump.clear();
+        reachableWithoutJump.insert(bb);
+    }
+
+#if 0
+    QTextStream out(stdout, QIODevice::WriteOnly);
+    out << "Jumps to ignore:" << endl;
+    foreach (Jump *j, removed) {
+        out << "\t" << j->id << ": ";
+        j->dump(out, Stmt::MIR);
+        out << endl;
+    }
+#endif
+
+    return optional;
+}
+
 void Optimizer::showMeTheCode(Function *function)
 {
     ::showMeTheCode(function);
diff --git a/src/qml/compiler/qv4ssa_p.h b/src/qml/compiler/qv4ssa_p.h
index ceaef9f938..fc84ffd551 100644
--- a/src/qml/compiler/qv4ssa_p.h
+++ b/src/qml/compiler/qv4ssa_p.h
@@ -141,6 +141,8 @@ public:
 
     QVector<LifeTimeInterval> lifeRanges() const;
 
+    QSet<V4IR::Jump *> calculateOptionalJumps();
+
     static void showMeTheCode(Function *function);
 
 private: