diff --git a/src/osg/Matrix_implementation.cpp b/src/osg/Matrix_implementation.cpp
index adf9d8a4e..d06638056 100644
--- a/src/osg/Matrix_implementation.cpp
+++ b/src/osg/Matrix_implementation.cpp
@@ -618,24 +618,26 @@ bool Matrix_implementation::invert_4x3( const Matrix_implementation& mat )
        return invert_4x3(tm);
     }
 
-    register value_type r00, r01, r02,
-                        r10, r11, r12,
-                        r20, r21, r22;
-      // Copy rotation components directly into registers for speed
-    r00 = mat._mat[0][0]; r01 = mat._mat[0][1]; r02 = mat._mat[0][2];
-    r10 = mat._mat[1][0]; r11 = mat._mat[1][1]; r12 = mat._mat[1][2];
-    r20 = mat._mat[2][0]; r21 = mat._mat[2][1]; r22 = mat._mat[2][2];
+    value_type r00 = mat._mat[0][0];
+    value_type r01 = mat._mat[0][1];
+    value_type r02 = mat._mat[0][2];
+    value_type r10 = mat._mat[1][0];
+    value_type r11 = mat._mat[1][1];
+    value_type r12 = mat._mat[1][2];
+    value_type r20 = mat._mat[2][0];
+    value_type r21 = mat._mat[2][1];
+    value_type r22 = mat._mat[2][2];
 
-        // Partially compute inverse of rot
+    // Partially compute inverse of rot
     _mat[0][0] = r11*r22 - r12*r21;
     _mat[0][1] = r02*r21 - r01*r22;
     _mat[0][2] = r01*r12 - r02*r11;
 
-      // Compute determinant of rot from 3 elements just computed
-    register value_type one_over_det = 1.0/(r00*_mat[0][0] + r10*_mat[0][1] + r20*_mat[0][2]);
+    // Compute determinant of rot from 3 elements just computed
+    value_type one_over_det = 1.0/(r00*_mat[0][0] + r10*_mat[0][1] + r20*_mat[0][2]);
     r00 *= one_over_det; r10 *= one_over_det; r20 *= one_over_det;  // Saves on later computations
 
-      // Finish computing inverse of rot
+    // Finish computing inverse of rot
     _mat[0][0] *= one_over_det;
     _mat[0][1] *= one_over_det;
     _mat[0][2] *= one_over_det;