PR rtl-optimization/39871

	PR rtl-optimization/40615
	PR rtl-optimization/42500
	PR rtl-optimization/42502
	* ira.c (init_reg_equiv_memory_loc: New function.
	(ira): Call it twice.
	* reload.h (calculate_elim_costs_all_insns): Declare.
	* ira-costs.c: Include "reload.h".
	(regno_equiv_gains): New static variable.
	(init_costs): Allocate it.
	(finish_costs): Free it.
	(ira_costs): Call calculate_elim_costs_all_insns.
	(find_costs_and_classes): Take estimated elimination costs
	into account.
	(ira_adjust_equiv_reg_cost): New function.
	* ira.h (ira_adjust_equiv_reg_cost): Declare it.
	* reload1.c (init_eliminable_invariants, free_reg_equiv,
	elimination_costs_in_insn, note_reg_elim_costly): New static
	functions.
	(elim_bb): New static variable.
	(reload): Move code out of here into init_eliminable_invariants and
	free_reg_equiv.  Call them.
	(calculate_elim_costs_all_insns): New function.
	(eliminate_regs_1): Declare.  Add extra arg FOR_COSTS;
	all callers changed.  If FOR_COSTS is true, don't call alter_reg,
	but call note_reg_elim_costly if we turned a valid memory address
	into an invalid one.
	* Makefile.in (ira-costs.o): Depend on reload.h.

testsuite/
	PR rtl-optimization/39871
	PR rtl-optimization/40615
	PR rtl-optimization/42500
	PR rtl-optimization/42502
	* gcc.target/arm/eliminate.c: New test.



git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@160260 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 32 insertions, 0 deletions

diff --git a/gcc/ira-costs.c b/gcc/ira-costs.c
index 491b86bb841..39955b64693 100644
--- a/gcc/ira-costs.c
+++ b/gcc/ira-costs.c
@@ -33,6 +33,7 @@ along with GCC; see the file COPYING3.  If not see
 #include "addresses.h"
 #include "insn-config.h"
 #include "recog.h"
+#include "reload.h"
 #include "toplev.h"
 #include "target.h"
 #include "params.h"
@@ -123,6 +124,10 @@ static enum reg_class *pref_buffer;
 /* Record cover register class of each allocno with the same regno.  */
 static enum reg_class *regno_cover_class;
 
+/* Record cost gains for not allocating a register with an invariant
+   equivalence.  */
+static int *regno_equiv_gains;
+
 /* Execution frequency of the current insn.  */
 static int frequency;
 
@@ -1263,6 +1268,7 @@ find_costs_and_classes (FILE *dump_file)
 #ifdef FORBIDDEN_INC_DEC_CLASSES
 	  int inc_dec_p = false;
 #endif
+	  int equiv_savings = regno_equiv_gains[i];
 
 	  if (! allocno_p)
 	    {
@@ -1311,6 +1317,15 @@ find_costs_and_classes (FILE *dump_file)
 #endif
 		}
 	    }
+	  if (equiv_savings < 0)
+	    temp_costs->mem_cost = -equiv_savings;
+	  else if (equiv_savings > 0)
+	    {
+	      temp_costs->mem_cost = 0;
+	      for (k = 0; k < cost_classes_num; k++)
+		temp_costs->cost[k] += equiv_savings;
+	    }
+
 	  best_cost = (1 << (HOST_BITS_PER_INT - 2)) - 1;
 	  best = ALL_REGS;
 	  alt_class = NO_REGS;
@@ -1680,6 +1695,8 @@ init_costs (void)
   regno_cover_class
     = (enum reg_class *) ira_allocate (sizeof (enum reg_class)
 				       * max_reg_num ());
+  regno_equiv_gains = (int *) ira_allocate (sizeof (int) * max_reg_num ());
+  memset (regno_equiv_gains, 0, sizeof (int) * max_reg_num ());
 }
 
 /* Common finalization function for ira_costs and
@@ -1687,6 +1704,7 @@ init_costs (void)
 static void
 finish_costs (void)
 {
+  ira_free (regno_equiv_gains);
   ira_free (regno_cover_class);
   ira_free (pref_buffer);
   ira_free (costs);
@@ -1702,6 +1720,7 @@ ira_costs (void)
   init_costs ();
   total_allocno_costs = (struct costs *) ira_allocate (max_struct_costs_size
 						       * ira_allocnos_num);
+  calculate_elim_costs_all_insns ();
   find_costs_and_classes (ira_dump_file);
   setup_allocno_cover_class_and_costs ();
   finish_costs ();
@@ -1802,3 +1821,16 @@ ira_tune_allocno_costs_and_cover_classes (void)
       }
     }
 }
+
+/* Add COST to the estimated gain for eliminating REGNO with its
+   equivalence.  If COST is zero, record that no such elimination is
+   possible.  */
+
+void
+ira_adjust_equiv_reg_cost (unsigned regno, int cost)
+{
+  if (cost == 0)
+    regno_equiv_gains[regno] = 0;
+  else
+    regno_equiv_gains[regno] += cost;
+}