[ARM] PR target/66731 Fix vnmul insn with -frounding-math

[ARM] PR target/66731 Fix vnmul insn with -frounding-math

gcc:

	PR target/66731
	* config/arm/vfp.md (negmuldf3_vfp): Add new pattern.
	(negmulsf3_vfp): Likewise.
	(muldf3negdf_vfp): Disable for -frounding-math.
	(mulsf3negsf_vfp): Likewise.
	* config/arm/arm.c (arm_new_rtx_costs): Fix NEG cost for VNMUL,
	fix MULT cost with -frounding-math.

gcc/testsuite:

	PR target/66731
	* gcc.target/arm/vnmul-1.c: New.
	* gcc.target/arm/vnmul-2.c: New.
	* gcc.target/arm/vnmul-3.c: New.
	* gcc.target/arm/vnmul-4.c: New.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@226496 138bc75d-0d04-0410-961f-82ee72b054a4