Remove global call sets: LRA

lra_reg has an actual_call_used_reg_set field that is only used during
inheritance.  This in turn required a special lra_create_live_ranges
pass for flag_ipa_ra to set up this field.  This patch instead makes
the inheritance code do its own live register tracking, using the
same ABI-mask-and-clobber-set pair as for IRA.

Tracking ABIs simplifies (and cheapens) the logic in lra-lives.c and
means we no longer need a separate path for -fipa-ra.  It also means
we can remove TARGET_RETURN_CALL_WITH_MAX_CLOBBERS.

The patch also strengthens the sanity check in lra_assigns so that
we check that reg_renumber is consistent with the whole conflict set,
not just the call-clobbered registers.

2019-09-30  Richard Sandiford  <richard.sandiford@arm.com>

gcc/
	* target.def (return_call_with_max_clobbers): Delete.
	* doc/tm.texi.in (TARGET_RETURN_CALL_WITH_MAX_CLOBBERS): Delete.
	* doc/tm.texi: Regenerate.
	* config/aarch64/aarch64.c (aarch64_return_call_with_max_clobbers)
	(TARGET_RETURN_CALL_WITH_MAX_CLOBBERS): Delete.
	* lra-int.h (lra_reg::actual_call_used_reg_set): Delete.
	(lra_reg::call_insn): Delete.
	* lra.c: Include function-abi.h.
	(initialize_lra_reg_info_element): Don't initialize the fields above.
	(lra): Use crtl->abi to test whether the current function needs to
	save a register in the prologue.  Remove special pre-inheritance
	lra_create_live_ranges pass for flag_ipa_ra.
	* lra-assigns.c: Include function-abi.h
	(find_hard_regno_for_1): Use crtl->abi to test whether the current
	function needs to save a register in the prologue.
	(lra_assign): Assert that registers aren't allocated to a
	conflicting register, rather than checking only for overlaps
	with call_used_or_fixed_regs.  Do this even for flag_ipa_ra,
	and for registers that are not live across a call.
	* lra-constraints.c (last_call_for_abi): New variable.
	(full_and_partial_call_clobbers): Likewise.
	(setup_next_usage_insn): Remove the register from
	full_and_partial_call_clobbers.
	(need_for_call_save_p): Use call_clobbered_in_region_p to test
	whether the register needs a caller save.
	(need_for_split_p): Use full_and_partial_reg_clobbers instead
	of call_used_or_fixed_regs.
	(inherit_in_ebb): Initialize and maintain last_call_for_abi and
	full_and_partial_call_clobbers.
	* lra-lives.c (check_pseudos_live_through_calls): Replace
	last_call_used_reg_set and call_insn arguments with an abi argument.
	Remove handling of lra_reg::call_insn.  Use function_abi::mode_clobbers
	as the set of conflicting registers.
	(calls_have_same_clobbers_p): Delete.
	(process_bb_lives): Track the ABI of the last call instead of an
	insn/HARD_REG_SET pair.  Update calls to
	check_pseudos_live_through_calls.  Use eh_edge_abi to calculate
	the set of registers that could be clobbered by an EH edge.
	Include partially-clobbered as well as fully-clobbered registers.
	(lra_create_live_ranges_1): Don't initialize lra_reg::call_insn.
	* lra-remat.c: Include function-abi.h.
	(call_used_regs_arr_len, call_used_regs_arr): Delete.
	(set_bb_regs): Use insn_callee_abi to get the set of call-clobbered
	registers and bitmap_view to combine them into dead_regs.
	(call_used_input_regno_present_p): Take a function_abi argument
	and use it to test whether a register is call-clobbered.
	(calculate_gen_cands): Use insn_callee_abi to get the ABI of the
	call insn target.  Update tje call to call_used_input_regno_present_p.
	(do_remat): Likewise.
	(lra_remat): Remove the initialization of call_used_regs_arr_len
	and call_used_regs_arr.

From-SVN: r276327

1 files changed, 6 insertions, 5 deletions

diff --git a/gcc/lra-assigns.c b/gcc/lra-assigns.c
index 014fb496..e14a246 100644
--- a/gcc/lra-assigns.c
+++ b/gcc/lra-assigns.c
@@ -94,6 +94,7 @@ along with GCC; see the file COPYING3.	If not see
 #include "params.h"
 #include "lra.h"
 #include "lra-int.h"
+#include "function-abi.h"
 
 /* Current iteration number of the pass and current iteration number
    of the pass after the latest spill pass when any former reload
@@ -654,7 +655,7 @@ find_hard_regno_for_1 (int regno, int *cost, int try_only_hard_regno,
 	  for (j = 0;
 	       j < hard_regno_nregs (hard_regno, PSEUDO_REGNO_MODE (regno));
 	       j++)
-	    if (! TEST_HARD_REG_BIT (call_used_or_fixed_regs, hard_regno + j)
+	    if (! crtl->abi->clobbers_full_reg_p (hard_regno + j)
 		&& ! df_regs_ever_live_p (hard_regno + j))
 	      /* It needs save restore.	 */
 	      hard_regno_costs[hard_regno]
@@ -1634,14 +1635,14 @@ lra_assign (bool &fails_p)
   bitmap_initialize (&all_spilled_pseudos, &reg_obstack);
   create_live_range_start_chains ();
   setup_live_pseudos_and_spill_after_risky_transforms (&all_spilled_pseudos);
-  if (! lra_asm_error_p && flag_checking && !flag_ipa_ra)
+  if (! lra_asm_error_p && flag_checking)
     /* Check correctness of allocation for call-crossed pseudos but
        only when there are no asm errors as in the case of errors the
        asm is removed and it can result in incorrect allocation.  */
     for (i = FIRST_PSEUDO_REGISTER; i < max_regno; i++)
-      if (lra_reg_info[i].nrefs != 0 && reg_renumber[i] >= 0
-	  && lra_reg_info[i].call_insn
-	  && overlaps_hard_reg_set_p (call_used_or_fixed_regs,
+      if (lra_reg_info[i].nrefs != 0
+	  && reg_renumber[i] >= 0
+	  && overlaps_hard_reg_set_p (lra_reg_info[i].conflict_hard_regs,
 				      PSEUDO_REGNO_MODE (i), reg_renumber[i]))
 	gcc_unreachable ();
   /* Setup insns to process on the next constraint pass.  */