Hello,

this patch fixes several ICEs when using constexpr SIMD vectors. Support 
for subscripting is still missing though, which is why I am not adding 
some static_asserts to the testcase. I don't use build_vector_from_ctor 
because it doesn't check for non-constant elements and doesn't handle 
vectors in a constructor (the middle-end produces those, and I expect the 
front-ends will too eventually).

Bootstrap+testsuite on x86_64-linux-gnu.

2012-11-29  Marc Glisse  <marc.glisse@inria.fr>

 	PR c++/53094
gcc/
 	* fold-const.c (fold): Replace a CONSTRUCTOR with a VECTOR_CST.
gcc/cp/
 	* cvt.c (ocp_convert): Call convert_to_vector.
gcc/testsuite/
 	* g++.dg/ext/vector20.C: New testcase.

-- 
Marc Glisse