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patch for elimination to SP when it is changed in RTL (PR57293)


  The following patch fixes PR57293

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=57293

  It is actually an implementation of missed LRA functionality in reg
elimination.  Before the patch any explicit change of stack pointer in
RTL resulted in necessity to use the frame pointer.

  The patch has practically no effect on generic tuning of x86/x86-64.
But it has a dramatic effect on code performance for other tunings
like corei7 which don't use incoming args accumulation.  The maximum
SPEC2000 improvement 2.5% is achieved on x86 SPECInt2000.  But
SPECFP2000 rate also has improvement about 1% on x86 and x86-64.  Too
bad that I did not implement it at the first place.  The results would
have been even much better ones reported on 2012 GNU Cauldron as I
also used -mtune=corei7 that time.

The patch was bootstrapped and tested on x86-64/x86 and ppc.

Committed as rev. 205498.

 2013-11-28  Vladimir Makarov<vmakarov@redhat.com>

	PR target/57293
	* ira.h (ira_setup_eliminable_regset): Remove parameter.
	* ira.c (ira_setup_eliminable_regset): Ditto.  Add
	SUPPORTS_STACK_ALIGNMENT for crtl->stack_realign_needed.
	Don't call lra_init_elimination.
	(ira): Call ira_setup_eliminable_regset without arguments.
	* loop-invariant.c (calculate_loop_reg_pressure): Remove argument
	from ira_setup_eliminable_regset call.
	* gcse.c (calculate_bb_reg_pressure): Ditto.
	* haifa-sched.c (sched_init): Ditto.
	* lra.h (lra_init_elimination): Remove the prototype.
	* lra-int.h (lra_insn_recog_data): New member sp_offset.  Move
	used_insn_alternative upper.
	(lra_eliminate_regs_1): Add one more parameter.
	(lra-eliminate): Ditto.
	* lra.c (lra_invalidate_insn_data): Set sp_offset.
	(setup_sp_offset): New.
	(lra_process_new_insns): Call setup_sp_offset.
	(lra): Add argument to lra_eliminate calls.
	* lra-constraints.c (get_equiv_substitution): Rename to get_equiv.
	(get_equiv_with_elimination): New.
	(process_addr_reg): Call get_equiv_with_elimination instead of
	get_equiv_substitution.
	(equiv_address_substitution): Ditto.
	(loc_equivalence_change_p): Ditto.
	(loc_equivalence_callback, lra_constraints): Ditto.
	(curr_insn_transform): Ditto.  Print the sp offset
	(process_alt_operands): Prevent stack pointer reloads.
	(lra_constraints): Remove one argument from lra_eliminate call.
	Move it up.  Mark used hard regs bfore it.  Use
	get_equiv_with_elimination instead of get_equiv_substitution.
	* lra-eliminations.c (lra_eliminate_regs_1): Add parameter and
	assert for param values combination.  Use sp offset.  Add argument
	to lra_eliminate_regs_1 calls.
	(lra_eliminate_regs): Add argument to lra_eliminate_regs_1 call.
	(curr_sp_change): New static var.
	(mark_not_eliminable): Add parameter.  Update curr_sp_change.
	Don't prevent elimination to sp if we can calculate its change.
	Pass the argument to mark_not_eliminable calls.
	(eliminate_regs_in_insn): Add a parameter.  Use sp offset.  Add
	argument to lra_eliminate_regs_1 call.
	(update_reg_eliminate): Move calculation of hard regs for spill
	lower.  Switch off lra_in_progress temporarily to generate regs
	involved into elimination.
	(lra_init_elimination): Rename to init_elimination.  Make it
	static.  Set up insn sp offset, check the offsets at the end of
	BBs.
	(process_insn_for_elimination): Add parameter.  Pass its value to
	eliminate_regs_in_insn.
	(lra_eliminate): : Add parameter.  Pass its value to
	process_insn_for_elimination.  Add assert for param values
	combination.  Call init_elimination.  Don't update offsets in
	equivalence substitutions.
	* lra-spills.c (assign_mem_slot): Don't call lra_eliminate_regs_1
	for created stack slot.
	(remove_pseudos): Call lra_eliminate_regs_1 before changing memory
	onto stack slot.

2013-11-28  Vladimir Makarov<vmakarov@redhat.com>

	PR target/57293
	* gcc.target/i386/pr57293.c: New.

Attachment: sp.patch
Description: Text document


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