[Bug tree-optimization/49442] [4.5/4.6/4.7 Regression] Misaligned store support pessimization

[irar at il dot ibm.com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49442

Ira Rosen <irar at il dot ibm.com> changed:

           What    |Removed                     |Added
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                 CC|                            |irar at il dot ibm.com

--- Comment #4 from Ira Rosen <irar at il dot ibm.com> 2011-06-19 08:25:05 UTC ---
We can try to fix this with the cost model and additional heuristic in
vect_enhance_data_refs_alignment. Currently we decide not to do versioning for
alignment, because all the accesses are supported anyway. Maybe something like
the following condition for versioning could help (when all the alignment
values are unknown):
if (number_of_loads * cost_of_misaligned_load 
    + number_of_stores * cost_of_misaligned_store
    + approx_vector_iteration_cost_without_drs >
    approx_scalar_iteration_cost * vectorization_factor)
  do_versioning = true;

Ira