ARMv8-M Security Extension's cmse_nonsecure_entry: clear registers

ARMv8-M Security Extension's cmse_nonsecure_entry: clear registers

    gcc/ChangeLog:
    2016-12-02  Andre Vieira  <andre.simoesdiasvieira@arm.com>
		Thomas Preud'homme  <thomas.preudhomme@arm.com>

	* config/arm/arm.c (output_return_instruction): Clear
	registers.
	(thumb2_expand_return): Likewise.
	(thumb1_expand_epilogue): Likewise.
	(thumb_exit): Likewise.
	(arm_expand_epilogue): Likewise.
	(cmse_nonsecure_entry_clear_before_return): New.
	(comp_not_to_clear_mask_str_un): New.
	(compute_not_to_clear_mask): New.
	* config/arm/thumb1.md (*epilogue_insns): Change length attribute.
	* config/arm/thumb2.md (*thumb2_return): Disable for
	cmse_nonsecure_entry functions.
	(*thumb2_cmse_entry_return): Duplicate thumb2_return pattern for
	cmse_nonsecure_entry functions.

    gcc/testsuite/ChangeLog:
    2016-12-02  Andre Vieira  <andre.simoesdiasvieira@arm.com>
		Thomas Preud'homme  <thomas.preudhomme@arm.com>

	* gcc.target/arm/cmse/cmse.exp: Test different multilibs separate.
	* gcc.target/arm/cmse/struct-1.c: New.
	* gcc.target/arm/cmse/bitfield-1.c: New.
	* gcc.target/arm/cmse/bitfield-2.c: New.
	* gcc.target/arm/cmse/bitfield-3.c: New.
	* gcc.target/arm/cmse/baseline/cmse-2.c: New.
	* gcc.target/arm/cmse/baseline/softfp.c: New.
	* gcc.target/arm/cmse/mainline/soft/cmse-5.c: New.
	* gcc.target/arm/cmse/mainline/hard/cmse-5.c: New.
	* gcc.target/arm/cmse/mainline/hard-sp/cmse-5.c: New.
	* gcc.target/arm/cmse/mainline/softfp/cmse-5.c: New.
	* gcc.target/arm/cmse/mainline/softfp-sp/cmse-5.c: New.

Co-Authored-By: Thomas Preud'homme <thomas.preudhomme@arm.com>
From-SVN: r243190