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, 34 insertions, 33 deletions

diff --git a/gcc/lra-remat.c b/gcc/lra-remat.c
index ea6e817..ee7ebf6 100644
--- a/gcc/lra-remat.c
+++ b/gcc/lra-remat.c
@@ -65,16 +65,11 @@ along with GCC; see the file COPYING3.	If not see
 #include "recog.h"
 #include "lra.h"
 #include "lra-int.h"
+#include "function-abi.h"
 
 /* Number of candidates for rematerialization.  */
 static unsigned int cands_num;
 
-/* The following is used for representation of call_used_or_fixed_regs in
-   form array whose elements are hard register numbers with nonzero bit
-   in CALL_USED_OR_FIXED_REGS. */
-static int call_used_regs_arr_len;
-static int call_used_regs_arr[FIRST_PSEUDO_REGISTER];
-
 /* Bitmap used for different calculations.  */
 static bitmap_head temp_bitmap;
 
@@ -633,9 +628,12 @@ set_bb_regs (basic_block bb, rtx_insn *insn)
 	bitmap_set_bit (&subreg_regs, regno);
     }
   if (CALL_P (insn))
-    for (int i = 0; i < call_used_regs_arr_len; i++)
-      bitmap_set_bit (&get_remat_bb_data (bb)->dead_regs,
-		      call_used_regs_arr[i]);
+    {
+      /* Partially-clobbered registers might still be live.  */
+      HARD_REG_SET clobbers = insn_callee_abi (insn).full_reg_clobbers ();
+      bitmap_ior_into (&get_remat_bb_data (bb)->dead_regs,
+		       bitmap_view<HARD_REG_SET> (clobbers));
+    }
 }
 
 /* Calculate changed_regs and dead_regs for each BB.  */
@@ -698,7 +696,7 @@ reg_overlap_for_remat_p (lra_insn_reg *reg, rtx_insn *insn)
 
 /* Return true if a call used register is an input operand of INSN.  */
 static bool
-call_used_input_regno_present_p (rtx_insn *insn)
+call_used_input_regno_present_p (const function_abi &abi, rtx_insn *insn)
 {
   int iter;
   lra_insn_recog_data_t id = lra_get_insn_recog_data (insn);
@@ -709,8 +707,9 @@ call_used_input_regno_present_p (rtx_insn *insn)
     for (reg = (iter == 0 ? id->regs : static_id->hard_regs);
 	 reg != NULL;
 	 reg = reg->next)
-      if (reg->type == OP_IN && reg->regno < FIRST_PSEUDO_REGISTER
-	  && TEST_HARD_REG_BIT (call_used_or_fixed_regs, reg->regno))
+      if (reg->type == OP_IN
+	  && reg->regno < FIRST_PSEUDO_REGISTER
+	  && abi.clobbers_reg_p (reg->biggest_mode, reg->regno))
 	return true;
   return false;
 }
@@ -799,18 +798,21 @@ calculate_gen_cands (void)
 		    }
 	    
 	    if (CALL_P (insn))
-	      EXECUTE_IF_SET_IN_BITMAP (gen_insns, 0, uid, bi)
-		{
-		  rtx_insn *insn2 = lra_insn_recog_data[uid]->insn;
+	      {
+		function_abi callee_abi = insn_callee_abi (insn);
+		EXECUTE_IF_SET_IN_BITMAP (gen_insns, 0, uid, bi)
+		  {
+		    rtx_insn *insn2 = lra_insn_recog_data[uid]->insn;
 		  
-		  cand = insn_to_cand[INSN_UID (insn2)];
-		  gcc_assert (cand != NULL);
-		  if (call_used_input_regno_present_p (insn2))
-		    {
-		      bitmap_clear_bit (gen_cands, cand->index);
-		      bitmap_set_bit (&temp_bitmap, uid);
-		    }
-		}
+		    cand = insn_to_cand[INSN_UID (insn2)];
+		    gcc_assert (cand != NULL);
+		    if (call_used_input_regno_present_p (callee_abi, insn2))
+		      {
+			bitmap_clear_bit (gen_cands, cand->index);
+			bitmap_set_bit (&temp_bitmap, uid);
+		      }
+		  }
+	      }
 	    bitmap_and_compl_into (gen_insns, &temp_bitmap);
 
 	    cand = insn_to_cand[INSN_UID (insn)];
@@ -1205,13 +1207,16 @@ do_remat (void)
 		  }
 
 	  if (CALL_P (insn))
-	    EXECUTE_IF_SET_IN_BITMAP (avail_cands, 0, cid, bi)
-	      {
-		cand = all_cands[cid];
+	    {
+	      function_abi callee_abi = insn_callee_abi (insn);
+	      EXECUTE_IF_SET_IN_BITMAP (avail_cands, 0, cid, bi)
+		{
+		  cand = all_cands[cid];
 		
-		if (call_used_input_regno_present_p (cand->insn))
-		  bitmap_set_bit (&temp_bitmap, cand->index);
-	      }
+		  if (call_used_input_regno_present_p (callee_abi, cand->insn))
+		    bitmap_set_bit (&temp_bitmap, cand->index);
+		}
+	    }
 
 	  bitmap_and_compl_into (avail_cands, &temp_bitmap);
 
@@ -1307,10 +1312,6 @@ lra_remat (void)
   insn_to_cand_activation = XCNEWVEC (cand_t, get_max_uid ());
   regno_cands = XCNEWVEC (cand_t, max_regno);
   all_cands.create (8000);
-  call_used_regs_arr_len = 0;
-  for (int i = 0; i < FIRST_PSEUDO_REGISTER; i++)
-    if (call_used_or_fixed_reg_p (i))
-      call_used_regs_arr[call_used_regs_arr_len++] = i;
   initiate_cand_table ();
   create_remat_bb_data ();
   bitmap_initialize (&temp_bitmap, &reg_obstack);