-fuse-caller-save - Support in lra

2014-05-28  Tom de Vries  <tom@codesourcery.com>

	* lra-int.h (struct lra_reg): Add field actual_call_used_reg_set.
	* lra.c (initialize_lra_reg_info_element): Add init of
	actual_call_used_reg_set field.
	(lra): Call lra_create_live_ranges before lra_inheritance for
	-fuse-caller-save.
	* lra-assigns.c (lra_assign): Allow call_used_regs to cross calls for
	-fuse-caller-save.
	* lra-constraints.c (need_for_call_save_p): Use actual_call_used_reg_set
	instead of call_used_reg_set for -fuse-caller-save.
	* lra-lives.c (process_bb_lives): Calculate actual_call_used_reg_set.

From-SVN: r211010

6 files changed, 57 insertions, 5 deletions

diff --git a/gcc/ChangeLog b/gcc/ChangeLog
index ba42f56..b0f47ae 100644
--- a/gcc/ChangeLog
+++ b/gcc/ChangeLog
@@ -1,3 +1,16 @@
+2014-05-28  Tom de Vries  <tom@codesourcery.com>
+
+	* lra-int.h (struct lra_reg): Add field actual_call_used_reg_set.
+	* lra.c (initialize_lra_reg_info_element): Add init of
+	actual_call_used_reg_set field.
+	(lra): Call lra_create_live_ranges before lra_inheritance for
+	-fuse-caller-save.
+	* lra-assigns.c (lra_assign): Allow call_used_regs to cross calls for
+	-fuse-caller-save.
+	* lra-constraints.c (need_for_call_save_p): Use actual_call_used_reg_set
+	instead of call_used_reg_set for -fuse-caller-save.
+	* lra-lives.c (process_bb_lives): Calculate actual_call_used_reg_set.
+
 2014-05-28  Radovan Obradovic  <robradovic@mips.com>
             Tom de Vries  <tom@codesourcery.com>
 
diff --git a/gcc/lra-assigns.c b/gcc/lra-assigns.c
index f7bb86b..34b4a11 100644
--- a/gcc/lra-assigns.c
+++ b/gcc/lra-assigns.c
@@ -1447,6 +1447,7 @@ lra_assign (void)
   bitmap_head insns_to_process;
   bool no_spills_p;
   int max_regno = max_reg_num ();
+  unsigned int call_used_reg_crosses_call = 0;
 
   timevar_push (TV_LRA_ASSIGN);
   init_lives ();
@@ -1459,14 +1460,22 @@ lra_assign (void)
   bitmap_initialize (&all_spilled_pseudos, &reg_obstack);
   create_live_range_start_chains ();
   setup_live_pseudos_and_spill_after_risky_transforms (&all_spilled_pseudos);
-#ifdef ENABLE_CHECKING
   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_p
 	&& overlaps_hard_reg_set_p (call_used_reg_set,
 				    PSEUDO_REGNO_MODE (i), reg_renumber[i]))
-      gcc_unreachable ();
-#endif
+      {
+	if (!flag_use_caller_save)
+	  gcc_unreachable ();
+	call_used_reg_crosses_call++;
+      }
+  if (lra_dump_file
+      && call_used_reg_crosses_call > 0)
+    fprintf (lra_dump_file,
+	     "Found %u pseudo(s) with a call used reg crossing a call.\n"
+	     "Allowing due to -fuse-caller-save\n",
+	     call_used_reg_crosses_call);    
   /* Setup insns to process on the next constraint pass.  */
   bitmap_initialize (&changed_pseudo_bitmap, &reg_obstack);
   init_live_reload_and_inheritance_pseudos ();
diff --git a/gcc/lra-constraints.c b/gcc/lra-constraints.c
index 2df841a..7eb9dbc 100644
--- a/gcc/lra-constraints.c
+++ b/gcc/lra-constraints.c
@@ -4605,7 +4605,10 @@ need_for_call_save_p (int regno)
   lra_assert (regno >= FIRST_PSEUDO_REGISTER && reg_renumber[regno] >= 0);
   return (usage_insns[regno].calls_num < calls_num
 	  && (overlaps_hard_reg_set_p
-	      (call_used_reg_set,
+	      ((flag_use_caller_save &&
+		! hard_reg_set_empty_p (lra_reg_info[regno].actual_call_used_reg_set))
+	       ? lra_reg_info[regno].actual_call_used_reg_set
+	       : call_used_reg_set,
 	       PSEUDO_REGNO_MODE (regno), reg_renumber[regno])
 	      || HARD_REGNO_CALL_PART_CLOBBERED (reg_renumber[regno],
 						 PSEUDO_REGNO_MODE (regno))));
diff --git a/gcc/lra-int.h b/gcc/lra-int.h
index 41c9849..98a3018 100644
--- a/gcc/lra-int.h
+++ b/gcc/lra-int.h
@@ -77,6 +77,10 @@ struct lra_reg
   /* The following fields are defined only for pseudos.	 */
   /* Hard registers with which the pseudo conflicts.  */
   HARD_REG_SET conflict_hard_regs;
+  /* Call used registers with which the pseudo conflicts, taking into account
+     the registers used by functions called from calls which cross the
+     pseudo. */
+  HARD_REG_SET actual_call_used_reg_set;
   /* We assign hard registers to reload pseudos which can occur in few
      places.  So two hard register preferences are enough for them.
      The following fields define the preferred hard registers.	If
diff --git a/gcc/lra-lives.c b/gcc/lra-lives.c
index 8444ade..d007215 100644
--- a/gcc/lra-lives.c
+++ b/gcc/lra-lives.c
@@ -624,6 +624,17 @@ process_bb_lives (basic_block bb, int &curr_point)
 
       if (call_p)
 	{
+	  if (flag_use_caller_save)
+	    {
+	      HARD_REG_SET this_call_used_reg_set;
+	      get_call_reg_set_usage (curr_insn, &this_call_used_reg_set,
+				      call_used_reg_set);
+
+	      EXECUTE_IF_SET_IN_SPARSESET (pseudos_live, j)
+		IOR_HARD_REG_SET (lra_reg_info[j].actual_call_used_reg_set,
+				  this_call_used_reg_set);
+	    }
+ 
 	  sparseset_ior (pseudos_live_through_calls,
 			 pseudos_live_through_calls, pseudos_live);
 	  if (cfun->has_nonlocal_label
diff --git a/gcc/lra.c b/gcc/lra.c
index ecec890..d199a81 100644
--- a/gcc/lra.c
+++ b/gcc/lra.c
@@ -1427,6 +1427,7 @@ initialize_lra_reg_info_element (int i)
   lra_reg_info[i].no_stack_p = false;
 #endif
   CLEAR_HARD_REG_SET (lra_reg_info[i].conflict_hard_regs);
+  CLEAR_HARD_REG_SET (lra_reg_info[i].actual_call_used_reg_set);
   lra_reg_info[i].preferred_hard_regno1 = -1;
   lra_reg_info[i].preferred_hard_regno2 = -1;
   lra_reg_info[i].preferred_hard_regno_profit1 = 0;
@@ -2344,7 +2345,18 @@ lra (FILE *f)
 	  lra_eliminate (false, false);
 	  /* Do inheritance only for regular algorithms.  */
 	  if (! lra_simple_p)
-	    lra_inheritance ();
+	    {
+	      if (flag_use_caller_save)
+		{
+		  if (live_p)
+		    lra_clear_live_ranges ();
+		  /* As a side-effect of lra_create_live_ranges, we calculate
+		     actual_call_used_reg_set,  which is needed during
+		     lra_inheritance.  */
+		  lra_create_live_ranges (true);
+		}
+	      lra_inheritance ();
+	    }
 	  if (live_p)
 	    lra_clear_live_ranges ();
 	  /* We need live ranges for lra_assign -- so build them.  */