From 33c33f6475910bad607abac67eef6c581d6188dd Mon Sep 17 00:00:00 2001
From: Oswald Buddenhagen <oswald.buddenhagen@qt.io>
Date: Fri, 16 Dec 2016 13:34:02 +0100
Subject: [PATCH] micro-optimize FOO-=$$BAR for empty FOO

there is no point in iterating BAR if FOO is (or became) empty.

Change-Id: I86c89bf0ad726a5ab7ead990a27ef7cc32caebbf
Reviewed-by: Joerg Bornemann <joerg.bornemann@qt.io>
---
 qmake/library/proitems.cpp | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/qmake/library/proitems.cpp b/qmake/library/proitems.cpp
index 66db190bc11..f41ace62316 100644
--- a/qmake/library/proitems.cpp
+++ b/qmake/library/proitems.cpp
@@ -396,9 +396,12 @@ void ProStringList::removeAll(const char *str)
 
 void ProStringList::removeEach(const ProStringList &value)
 {
-    for (const ProString &str : value)
+    for (const ProString &str : value) {
+        if (isEmpty())
+            break;
         if (!str.isEmpty())
             removeAll(str);
+    }
 }
 
 void ProStringList::removeEmpty()