ira.h (target_ira): Add x_ira_class_singleton.

gcc/
	* ira.h (target_ira): Add x_ira_class_singleton.
	(ira_class_singleton): New macro.
	* ira.c (setup_prohibited_class_mode_regs): Set up ira_class_singleton.
	* ira-build.c (update_conflict_hard_reg_costs): Use
	ira_class_singleton to check for classes with a single
	allocatable register.
	* ira-lives.c (ira_implicitly_set_insn_hard_regs): Likewise.
	(single_reg_class): Likewise.  When more than one class is specified,
	check whether they have the same singleton register.
	(process_single_reg_class_operands): Require single_reg_class
	to return NO_REGS or a class with a single allocatable register.
	Obtain that register from ira_class_singleton.

From-SVN: r191995

1 files changed, 14 insertions, 2 deletions

diff --git a/gcc/ira.c b/gcc/ira.c
index ad0ae0a..8436f60 100644
--- a/gcc/ira.c
+++ b/gcc/ira.c
@@ -1451,16 +1451,21 @@ setup_reg_class_nregs (void)
 
 
 
-/* Set up IRA_PROHIBITED_CLASS_MODE_REGS.  */
+/* Set up IRA_PROHIBITED_CLASS_MODE_REGS and IRA_CLASS_SINGLETON.
+   This function is called once IRA_CLASS_HARD_REGS has been initialized.  */
 static void
 setup_prohibited_class_mode_regs (void)
 {
-  int j, k, hard_regno, cl;
+  int j, k, hard_regno, cl, last_hard_regno, count;
 
   for (cl = (int) N_REG_CLASSES - 1; cl >= 0; cl--)
     {
+      COPY_HARD_REG_SET (temp_hard_regset, reg_class_contents[cl]);
+      AND_COMPL_HARD_REG_SET (temp_hard_regset, no_unit_alloc_regs);
       for (j = 0; j < NUM_MACHINE_MODES; j++)
 	{
+	  count = 0;
+	  last_hard_regno = -1;
 	  CLEAR_HARD_REG_SET (ira_prohibited_class_mode_regs[cl][j]);
 	  for (k = ira_class_hard_regs_num[cl] - 1; k >= 0; k--)
 	    {
@@ -1468,7 +1473,14 @@ setup_prohibited_class_mode_regs (void)
 	      if (! HARD_REGNO_MODE_OK (hard_regno, (enum machine_mode) j))
 		SET_HARD_REG_BIT (ira_prohibited_class_mode_regs[cl][j],
 				  hard_regno);
+	      else if (in_hard_reg_set_p (temp_hard_regset,
+					  (enum machine_mode) j, hard_regno))
+		{
+		  last_hard_regno = hard_regno;
+		  count++;
+		}
 	    }
+	  ira_class_singleton[cl][j] = (count == 1 ? last_hard_regno : -1);
 	}
     }
 }