Improve while(true/false) condition generation

Both in while-loops and in do-while-loops.

Change-Id: I50be52e3ea6ecb9ce6886e6da03c35a1790a45e8
Reviewed-by: Simon Hausmann <simon.hausmann@qt.io>

1 files changed, 12 insertions, 2 deletions

diff --git a/src/qml/compiler/qv4codegen.cpp b/src/qml/compiler/qv4codegen.cpp
index 3fa422a579..824cb77e7a 100644
--- a/src/qml/compiler/qv4codegen.cpp
+++ b/src/qml/compiler/qv4codegen.cpp
@@ -2273,7 +2273,13 @@ bool Codegen::visit(DoWhileStatement *ast)
     statement(ast->statement);
 
     cond.link();
-    condition(ast->expression, &body, &end, false);
+
+    if (!AST::cast<FalseLiteral *>(ast->expression)) {
+        if (AST::cast<TrueLiteral *>(ast->expression))
+            bytecodeGenerator->jump().link(body);
+        else
+            condition(ast->expression, &body, &end, false);
+    }
 
     end.link();
 
@@ -2718,6 +2724,9 @@ bool Codegen::visit(WhileStatement *ast)
     if (hasError)
         return true;
 
+    if (AST::cast<FalseLiteral *>(ast->expression))
+        return false;
+
     RegisterScope scope(this);
 
     BytecodeGenerator::Label start = bytecodeGenerator->newLabel();
@@ -2725,7 +2734,8 @@ bool Codegen::visit(WhileStatement *ast)
     BytecodeGenerator::Label cond = bytecodeGenerator->label();
     ControlFlowLoop flow(this, &end, &cond);
 
-    condition(ast->expression, &start, &end, true);
+    if (!AST::cast<TrueLiteral *>(ast->expression))
+        condition(ast->expression, &start, &end, true);
 
     start.link();
     statement(ast->statement);