Handle Octeon 3 not supporting MIPS paired-single instructions.

Handle Octeon 3 not supporting MIPS paired-single instructions.

The Octeon 3 processor does not support the MIPS paired-single
instructions.  This results in illegal instruction errors in the
testsuite when vectorization tests try to use those instructions.

This patch teaches the compiler about that lack of support, so that
warnings are given when -mpaired-single (or something implying it) is
used when compiling for such a processor.  I chose to test
TARGET_OCTEON as the simplest conditional; since the older Octeon
processors don't support hard float at all, I don't think the choice
matters for them.  Tests that then failed with the warning were
updated to disable them for Octeon.

Tested with no regressions for cross to mips64el-linux-gnu (Octeon
3).

gcc:
	* config/mips/mips.h (ISA_HAS_PAIRED_SINGLE): Require
	!TARGET_OCTEON.

gcc/testsuite:
	* gcc.target/mips/mips-3d-1.c: Use forbid_cpu=octeon.* in
	dg-options.
	* gcc.target/mips/mips-3d-2.c: Likewise.
	* gcc.target/mips/mips-3d-3.c: Likewise.
	* gcc.target/mips/mips-3d-4.c: Likewise.
	* gcc.target/mips/mips-3d-5.c: Likewise.
	* gcc.target/mips/mips-3d-6.c: Likewise.
	* gcc.target/mips/mips-3d-7.c: Likewise.
	* gcc.target/mips/mips-3d-8.c: Likewise.
	* gcc.target/mips/mips-3d-9.c: Likewise.
	* gcc.target/mips/mips-ps-1.c: Likewise.
	* gcc.target/mips/mips-ps-2.c: Likewise.
	* gcc.target/mips/mips-ps-3.c: Likewise.
	* gcc.target/mips/mips-ps-4.c: Likewise.
	* gcc.target/mips/mips-ps-5.c: Likewise.
	* gcc.target/mips/mips-ps-6.c: Likewise.
	* gcc.target/mips/mips-ps-7.c: Likewise.
	* gcc.target/mips/mips-ps-type.c: Likewise.
	* gcc.target/mips/mips-ps-type-2.c: Likewise.
	* gcc.target/mips/mips16-attributes-6.c: Likewise.

From-SVN: r232517