This is a resubmission of patch 1 to support the Aarch64 SIMD ABI [1] in
GCC, it does not have any functional changes from the last submit.

The significant difference between the standard ARM ABI and the SIMD ABI
is that in the normal ABI a callee saves only the lower 64 bits of registers
V8-V15, in the SIMD ABI the callee must save all 128 bits of registers
V8-V23.

This patch checks for SIMD functions and saves the extra registers when
needed.  It does not change the caller behavour, so with just this patch
there may be values saved by both the caller and callee.  This is not
efficient, but it is correct code. Patches 3 and 4 will remove the extra
saves from the caller.

Steve Ellcey
sellcey@cavium.com


2018-11-08  Steve Ellcey  <sellcey@cavium.com>

	* config/aarch64/aarch64-protos.h (aarch64_use_simple_return_insn_p):
	New prototype.
	(aarch64_epilogue_uses): Ditto.
	* config/aarch64/aarch64.c (aarch64_attribute_table): New array.
	(aarch64_simd_decl_p): New function.
	(aarch64_reg_save_mode): New function.
	(aarch64_function_ok_for_sibcall): Check for simd calls.
	(aarch64_layout_frame): Check for simd function.
	(aarch64_gen_storewb_pair): Handle E_TFmode.
	(aarch64_push_regs): Use aarch64_reg_save_mode to get mode.
	(aarch64_gen_loadwb_pair): Handle E_TFmode.
	(aarch64_pop_regs): Use aarch64_reg_save_mode to get mode.
	(aarch64_gen_store_pair): Handle E_TFmode.
	(aarch64_gen_load_pair): Ditto.
	(aarch64_save_callee_saves): Handle different mode sizes.
	(aarch64_restore_callee_saves): Ditto.
	(aarch64_components_for_bb): Check for simd function.
	(aarch64_epilogue_uses): New function.
	(aarch64_process_components): Check for simd function.
	(aarch64_expand_prologue): Ditto.
	(aarch64_expand_epilogue): Ditto.
	(aarch64_expand_call): Ditto.
	(aarch64_use_simple_return_insn_p): New function.
	(TARGET_ATTRIBUTE_TABLE): New define.
	* config/aarch64/aarch64.h (EPILOGUE_USES): Redefine.
	(FP_SIMD_SAVED_REGNUM_P): New macro.
	* config/aarch64/aarch64.md (simple_return): New define_expand.
	(load_pair_dw_tftf): New instruction.
	(store_pair_dw_tftf): Ditto.
	(loadwb_pair<TX:mode>_<P:mode>): Ditto.
	(storewb_pair<TX:mode>_<P:mode>): Ditto.


2018-11-08  Steve Ellcey  <sellcey@cavium.com>

	* gcc.target/aarch64/torture/aarch64-torture.exp: New file.
	* gcc.target/aarch64/torture/simd-abi-1.c: New test.
	* gcc.target/aarch64/torture/simd-abi-2.c: Ditto.
	* gcc.target/aarch64/torture/simd-abi-3.c: Ditto.
	* gcc.target/aarch64/torture/simd-abi-4.c: Ditto.
	* gcc.target/aarch64/torture/simd-abi-5.c: Ditto.