QLayoutPolicy: use qCountTrailingZeroBits() in setControlType()

This is more efficient, because it maps to a single assembler
instruction on most ISAs, and also avoids a Coverity warning about the
loop not terminating and thus 1 << i overflowing, if type == {}.

The clone class, QSizePolicy, is not affected, since it already uses
qCountTrailingZeroBits().

Amends 6c322a917ad57d57f0ee76825eab3e2e008c5bd4.

Coverity-Id: 474336
Pick-to: 6.9 6.8 6.5
Change-Id: Idf62d045d8ac3f0cb15196dd8664ac37d92a9cc2
Reviewed-by: Thiago Macieira <[email protected]>

1 files changed, 1 insertions, 9 deletions

diff --git a/src/gui/util/qlayoutpolicy.cpp b/src/gui/util/qlayoutpolicy.cpp
index 2e3a0b32cb5..3e6cb27c1b7 100644
--- a/src/gui/util/qlayoutpolicy.cpp
+++ b/src/gui/util/qlayoutpolicy.cpp
@@ -22,15 +22,7 @@ void QLayoutPolicy::setControlType(ControlType type)
             0x00000008 maps to 3
             etc.
     */
-
-    int i = 0;
-    while (true) {
-        if (type & (0x1 << i)) {
-            bits.ctype = i;
-            return;
-        }
-        ++i;
-    }
+    bits.ctype = qCountTrailingZeroBits(quint32(type));
 }
 
 QLayoutPolicy::ControlType QLayoutPolicy::controlType() const