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[Lapack] Acces to uninitialized values in xlarfb.f


I discovered a corner case in xlarfb.f where the diagonal of V is 
accessed by ilazlr call when it shouldn't because the diagonal is 
composed of 1.

The case I used is the following:
     dlarfb( 'L', 'T', 'F', 'C', 1, 1, 1, ...)

But it happens in all different cases during the calls to ilazlr and 
ilazlc when the M or N are equal to 1, or if the V matrix is full of 
zero because the first non zero element found will be one of the 
diagonal element.
Due to those boundary conditions tests in ilazlc or ilazlr can be done 
on uninitialized values and can not be trusted.


Mathieu Faverge
Maitre de conf?rence / Assistant Professor
Institut Polytechnique de Bordeaux - ENSEIRB-Matmeca
INRIA Bordeaux - Sud-Ouest, HiePACS Team
200 avenue de la vielle tour
33405 Talence Cedex
Phone: (+33) 5 24 57 40 73

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