From b8b0d01c91b794dc41cf9a0b06b7357b30678d10 Mon Sep 17 00:00:00 2001
From: Tomas Frydrych <tf@openedhand.com>
Date: Fri, 19 Jan 2007 20:00:41 +0000
Subject: [PATCH] work around punned-pointer problem

---
 ChangeLog               |  7 +++++++
 clutter/clutter-fixed.c | 27 +++++++++++++++------------
 2 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/ChangeLog b/ChangeLog
index ff735655c..6a3c89746 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2007-01-19  Tomas Frydrych  <tf@openedhand.com>
+
+	* clutter/clutter-fixed.c: (clutter_sqrti):
+	Use union instead of casting int <-> float to get rid of 
+	punned-pointer warning and avoid gcc optimatisation breaking
+	the function on arm.
+	
 2007-01-19  Emmanuele Bassi  <ebassi@openedhand.com>
 
 	Allow the ClutterGroup subclasses to override the add and
diff --git a/clutter/clutter-fixed.c b/clutter/clutter-fixed.c
index 92d37d7ae..c0ac9075f 100644
--- a/clutter/clutter-fixed.c
+++ b/clutter/clutter-fixed.c
@@ -470,17 +470,21 @@ clutter_sqrti (gint number)
      * elsewhere in clutter is not good enough, and 10.22 is used instead.
      */
     ClutterFixed x;
-    unsigned long y, y1;        /* 10.22 fixed point */
+    unsigned long y1;        /* 10.22 fixed point */
     unsigned long f = 0x600000; /* '1.5' as 10.22 fixed */
-    float flt = number;
-    float flt2;
+
+    union
+    {
+	float f;
+	unsigned long i;
+    } flt, flt2;
+    
+    flt.f = number;
     
     x = CLUTTER_INT_TO_FIXED (number) / 2;
 
     /* The QIII initial estimate */
-    y   = * ( unsigned long * ) &flt;
-    y   = 0x5f3759df - ( y >> 1 );
-    flt = * ( float * ) &y;
+    flt.i = 0x5f3759df - ( flt.i >> 1 );
 
     /* Now, we convert the float to 10.22 fixed. We exploit the mechanism
      * described at http://www.d6.com/users/checker/pdfs/gdmfp.pdf.
@@ -494,22 +498,21 @@ clutter_sqrti (gint number)
      * addition out, and it all goes pear shape, since without it, the bits
      * in the float will not be correctly aligned.
      */
-    flt2 = flt + 2.0;
-    y   = * ( long * ) &flt2;
-    y &= 0x7FFFFF;
+    flt2.f = flt.f + 2.0;
+    flt2.i &= 0x7FFFFF;
 
     /* Now we correct the estimate, only single iterration is needed */
-    y1 = (y >> 11) * (y >> 11);
+    y1 = (flt2.i >> 11) * (flt2.i >> 11);
     y1 = (y1 >> 8) * (x >> 8);
 
     y1 = f - y1;
-    y  = (y >> 11) * (y1 >> 11);
+    flt2.i = (flt2.i >> 11) * (y1 >> 11);
 
     /* Invert, round and convert from 10.22 to an integer
      * 0x1e3c68 is a magical rounding constant that produces slightly
      * better results than 0x200000.
      */
-    return (number * y + 0x1e3c68) >> 22;
+    return (number * flt2.i + 0x1e3c68) >> 22;
 }
 
 /* <private> */