simplify-rtx.c (simplify_subreg): Reduce problem of finding vector mode subregs of constants to finding integer...

gcc:
	* simplify-rtx.c (simplify_subreg): Reduce problem of finding
	vector mode subregs of constants to finding integer mode
	subregs of constants.
	* cse.c (cse_insn): Use simplify_gen_subreg.
	* convert.c (convert_to_integer): Don't strip a NOP_EXPR
	From a vector mode expression of different size than the
	target mode.
gcc/testsuite:
	* gcc.c-torture/compile/simd-3.c: New test.

From-SVN: r55234