re PR target/61578 (Code size increase for ARM thumb compared to 4.8.x when compiling with -Os)

2015-09-01  Vladimir Makarov  <vmakarov@redhat.com>

	PR target/61578
	* lra-lives.c (process_bb_lives): Process move pseudos with the
	same value for copies and preferences
	* lra-constraints.c (match_reload): Create match reload pseudo
	with the same value from single dying input pseudo.

From-SVN: r227382

gcc/ChangeLog

+2015-09-01  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR target/61578
+	* lra-lives.c (process_bb_lives): Process move pseudos with the
+	same value for copies and preferences
+	* lra-constraints.c (match_reload): Create match reload pseudo
+	with the same value from single dying input pseudo.
+
 2015-09-01  Ilya Enkovich  <enkovich.gnu@gmail.com>
 
 	PR target/67405

gcc/lra-constraints.c

@@ -928,10 +928,12 @@ match_reload (signed char out, signed char *ins, enum reg_class goal_class,
 	 they live in the same place.  When we create a pseudo we
 	 assign value of original pseudo (if any) from which we
 	 created the new pseudo.  If we create the pseudo from the
-	 input pseudo, the new pseudo will no conflict with the input
-	 pseudo which is wrong when the input pseudo lives after the
-	 insn and as the new pseudo value is changed by the insn
-	 output.  Therefore we create the new pseudo from the output.
+	 input pseudo, the new pseudo will have no conflict with the
+	 input pseudo which is wrong when the input pseudo lives after
+	 the insn and as the new pseudo value is changed by the insn
+	 output.  Therefore we create the new pseudo from the output
+	 except the case when we have single matched dying input
+	 pseudo.
 
 	 We cannot reuse the current output register because we might
 	 have a situation like "a <- a op b", where the constraints
@@ -940,8 +942,12 @@ match_reload (signed char out, signed char *ins, enum reg_class goal_class,
 	 so that it doesn't clobber the current value of "a".  */
 
       new_in_reg = new_out_reg
-	= lra_create_new_reg_with_unique_value (outmode, out_rtx,
-						goal_class, "");
+	= (ins[1] < 0 && REG_P (in_rtx)
+	   && (int) REGNO (in_rtx) < lra_new_regno_start
+	   && find_regno_note (curr_insn, REG_DEAD, REGNO (in_rtx))
+	   ? lra_create_new_reg (inmode, in_rtx, goal_class, "")
+	   : lra_create_new_reg_with_unique_value (outmode, out_rtx,
+						   goal_class, ""));
     }
   /* In operand can be got from transformations before processing insn
      constraints.  One example of such transformations is subreg

gcc/lra-lives.c

@@ -726,28 +726,33 @@ process_bb_lives (basic_block bb, int &curr_point, bool dead_insn_p)
 	  lra_hard_reg_usage[reg->regno] += freq;
 
       call_p = CALL_P (curr_insn);
+      src_regno = (set != NULL_RTX && REG_P (SET_SRC (set))
+		   ? REGNO (SET_SRC (set)) : -1);
+      dst_regno = (set != NULL_RTX && REG_P (SET_DEST (set))
+		   ? REGNO (SET_DEST (set)) : -1);
       if (complete_info_p
-	  && set != NULL_RTX
-	  && REG_P (SET_DEST (set)) && REG_P (SET_SRC (set))
+	  && src_regno >= 0 && dst_regno >= 0
 	  /* Check that source regno does not conflict with
 	     destination regno to exclude most impossible
 	     preferences.  */
-	  && ((((src_regno = REGNO (SET_SRC (set))) >= FIRST_PSEUDO_REGISTER
-		&& ! sparseset_bit_p (pseudos_live, src_regno))
+	  && (((src_regno >= FIRST_PSEUDO_REGISTER
+		&& (! sparseset_bit_p (pseudos_live, src_regno)
+		    || (dst_regno >= FIRST_PSEUDO_REGISTER
+			&& lra_reg_val_equal_p (src_regno,
+						lra_reg_info[dst_regno].val,
+						lra_reg_info[dst_regno].offset))))
 	       || (src_regno < FIRST_PSEUDO_REGISTER
 		   && ! TEST_HARD_REG_BIT (hard_regs_live, src_regno)))
 	      /* It might be 'inheritance pseudo <- reload pseudo'.  */
 	      || (src_regno >= lra_constraint_new_regno_start
-		  && ((int) REGNO (SET_DEST (set))
-		      >= lra_constraint_new_regno_start)
+		  && dst_regno >= lra_constraint_new_regno_start
 		  /* Remember to skip special cases where src/dest regnos are
 		     the same, e.g. insn SET pattern has matching constraints
 		     like =r,0.  */
-		  && src_regno != (int) REGNO (SET_DEST (set)))))
+		  && src_regno != dst_regno)))
 	{
 	  int hard_regno = -1, regno = -1;
 
-	  dst_regno = REGNO (SET_DEST (set));
 	  if (dst_regno >= lra_constraint_new_regno_start
 	      && src_regno >= lra_constraint_new_regno_start)
 	    {