[og9] Backport AMD GCN backend improvements from mainline

[og9] Backport AMD GCN backend improvements from mainline

2019-11-07  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* ira.c (setup_alloc_regs): Setup no_unit_alloc_regs for
	frame pointer in multiple registers.
	(ira_setup_eliminable_regset): Setup eliminable_regset,
	ira_no_alloc_regs and regs_ever_live for frame pointer in
	multiple registers.

2019-11-10  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* lra-spills.c (assign_spill_hard_regs): Do not spill into
	registers in eliminable_regset.

2019-11-14  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* lra-spills.c (assign_spill_hard_regs): Check that the spill
	register is suitable for the mode.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (gcn_regno_reg_class): Return VCC_CONDITIONAL_REG
	register class for VCC_LO and VCC_HI.
	(gcn_spill_class): Use SGPR_REGS to spill registers in
	VCC_CONDITIONAL_REG.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (gcn_expand_prologue): Remove initialization and
	prologue use of v0.
	(print_operand_address): Use v1 for zero vector offset.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (gcn_init_cumulative_args): Call reinit_regs.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (default_requested_args): New.
	(gcn_parse_amdgpu_hsa_kernel_attribute): Initialize requested args
	set with default_requested_args.
	(gcn_conditional_register_usage): Limit register usage of non-kernel
	functions.  Reassign fixed registers if a non-standard set of args is
	requested.
	* config/gcn/gcn.h (FIXED_REGISTERS): Fix registers according to ABI.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.c (MAX_NORMAL_SGPR_COUNT, MAX_NORMAL_VGPR_COUNT): New.
	(gcn_conditional_register_usage): Use constants in place of hard-coded
	values.
	(gcn_hsa_declare_function_name): Set lower bound for number of
	SGPRs/VGPRs in non-leaf kernels to MAX_NORMAL_SGPR_COUNT and
	MAX_NORMAL_VGPR_COUNT.

2019-11-15  Kwok Cheung Yeung  <kcy@codesourcery.com>

	gcc/
	* config/gcn/gcn.h (FIXED_REGISTERS): Unfix frame pointer.
	(CALL_USED_REGISTERS): Make frame pointer callee-saved.

(cherry picked from openacc-gcc-9-branch commit
20245bf2e0b8ac258f86e6495b3be3e09edd0181, and commit
e4005e490429a9595aee002528e0bf71281cb188)