re PR target/45074 (GCC Segmentation fault - negating global register variables)

re PR target/45074 (GCC Segmentation fault - negating global register variables)

gcc/
	PR target/45074
	* optabs.h (valid_multiword_target_p): Declare.
	* expmed.c (extract_bit_field_1): Check valid_multiword_target_p when
	doing multi-word operations.
	* optabs.c (expand_binop): Likewise.
	(expand_doubleword_bswap): Likewise.
	(expand_absneg_bit): Likewise.
	(expand_unop): Likewise.
	(expand_copysign_bit): Likewise.
	(multiword_target_p): New function.

gcc/testsuite/
	PR target/45074
	* gcc.target/mips/pr45074.c: New test.

From-SVN: r174541