Patchwork Commited: fix epiphany data flow / mode switching problem

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Submitter Joern Rennecke
Date May 13, 2013, 12:40 a.m.
Message ID <20130512204013.sp5y97czcwkk8ssg-nzlynne@webmail.spamcop.net>
Download mbox | patch
Permalink /patch/243226/
State New
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Comments

Joern Rennecke - May 13, 2013, 12:40 a.m.
Data flow based optimizations between mode switching and the emitting of the
prologue code have become more aggressive, making it necessary to emit
the saving of the config register during mode switching, lest mode switching
instructions are deleted.

Committed to trunk and gcc-4_8-branch.
2013-05-12  Joern Rennecke  <joern.rennecke@embecosm.com>

	* config/epiphany/epiphany.c (epiphany_init): Check size of
	NUM_MODES_FOR_MODE_SWITCHING.
	(epiphany_expand_prologue):
	Remove CONFIG_REGNUM initial value handling code.
	(epiphany_optimize_mode_switching): Handle EPIPHANY_MSW_ENTITY_CONFIG.
	(epiphany_mode_needed, epiphany_mode_entry_exit): Likewise.
	(emit_set_fp_mode, epiphany_mode_after): Likewise.
	(epiphany_mode_needed) <Handle EPIPHANY_MSW_ENTITY_AND>:
	Don't return 1 for FP_MODE_NONE.
	* config/epiphany/epiphany.h (NUM_MODES_FOR_MODE_SWITCHING):
	Add value for EPIPHANY_MSW_ENTITY_CONFIG.
	(EPIPHANY_MSW_ENTITY_CONFIG, EPIPHANY_MSW_ENTITY_NUM): Define.
	* config/epiphany/epiphany.md (save_config): New pattern.

Patch

Index: config/epiphany/epiphany.c
===================================================================
--- config/epiphany/epiphany.c	(revision 198806)
+++ config/epiphany/epiphany.c	(working copy)
@@ -181,6 +181,8 @@  epiphany_init (void)
     = { &pass_split_all_insns.pass, "mode_sw",
 	1, PASS_POS_INSERT_AFTER
       };
+  static const int num_modes[] = NUM_MODES_FOR_MODE_SWITCHING;
+#define N_ENTITIES ARRAY_SIZE (num_modes)
 
   epiphany_init_reg_tables ();
 
@@ -196,6 +198,8 @@  epiphany_init (void)
   register_pass (&mode_sw3_info);
   register_pass (&insert_use_info);
   register_pass (&mode_sw2_info);
+  /* Verify that NUM_MODES_FOR_MODE_SWITCHING has one value per entity.  */
+  gcc_assert (N_ENTITIES == EPIPHANY_MSW_ENTITY_NUM);
 
 #if 1 /* As long as peep2_rescan is not implemented,
          (see http://gcc.gnu.org/ml/gcc-patches/2011-10/msg02819.html,)
@@ -1773,44 +1777,6 @@  epiphany_expand_prologue (void)
 	}
       frame_insn (gen_stack_adjust_add (off, mem));
     }
-
-  /* Mode switching uses get_hard_reg_initial_val after
-      emit_initial_value_sets, so we have to fix this up now.  */
-  save_config = has_hard_reg_initial_val (SImode, CONFIG_REGNUM);
-  if (save_config)
-    {
-      if (REG_P (save_config))
-	{
-	  if (REGNO (save_config) >= FIRST_PSEUDO_REGISTER)
-	    gcc_assert (!df_regs_ever_live_p (REGNO (save_config)));
-	  else
-	    frame_move_insn (save_config,
-			     get_hard_reg_initial_reg (save_config));
-	}
-      else
-	{
-	  rtx save_dst = save_config;
-
-	  reg = gen_rtx_REG (SImode, GPR_IP);
-	  gcc_assert (MEM_P (save_dst));
-	  if (!memory_operand (save_dst, SImode))
-	    {
-	      rtx addr = XEXP (save_dst, 0);
-	      rtx reg2 = gen_rtx_REG (SImode, GPR_16);
-
-	      gcc_assert (GET_CODE (addr) == PLUS);
-	      gcc_assert (XEXP (addr, 0) == hard_frame_pointer_rtx
-			  || XEXP (addr, 0) == stack_pointer_rtx);
-	      emit_move_insn (reg2, XEXP (addr, 1));
-	      save_dst
-		= replace_equiv_address (save_dst,
-					 gen_rtx_PLUS (Pmode, XEXP (addr, 0),
-						       reg2));
-	    }
-	  emit_move_insn (reg, get_hard_reg_initial_reg (save_config));
-	  emit_move_insn (save_dst, reg);
-	}
-    }
 }
 
 void
@@ -2271,6 +2237,7 @@  epiphany_optimize_mode_switching (int en
     {
     case EPIPHANY_MSW_ENTITY_AND:
     case EPIPHANY_MSW_ENTITY_OR:
+    case EPIPHANY_MSW_ENTITY_CONFIG:
       return true;
     case EPIPHANY_MSW_ENTITY_NEAREST:
     case EPIPHANY_MSW_ENTITY_TRUNC:
@@ -2289,7 +2256,8 @@  epiphany_optimize_mode_switching (int en
 int
 epiphany_mode_priority_to_mode (int entity, unsigned priority)
 {
-  if (entity == EPIPHANY_MSW_ENTITY_AND || entity == EPIPHANY_MSW_ENTITY_OR)
+  if (entity == EPIPHANY_MSW_ENTITY_AND || entity == EPIPHANY_MSW_ENTITY_OR
+      || entity== EPIPHANY_MSW_ENTITY_CONFIG)
     return priority;
   if (priority > 3)
     switch (priority)
@@ -2341,7 +2309,8 @@  epiphany_mode_needed (int entity, rtx in
   if (recog_memoized (insn) < 0)
     {
       if (entity == EPIPHANY_MSW_ENTITY_AND
-	  || entity == EPIPHANY_MSW_ENTITY_OR)
+	  || entity == EPIPHANY_MSW_ENTITY_OR
+	  || entity == EPIPHANY_MSW_ENTITY_CONFIG)
 	return 2;
       return FP_MODE_NONE;
     }
@@ -2350,9 +2319,24 @@  epiphany_mode_needed (int entity, rtx in
   switch (entity)
   {
   case EPIPHANY_MSW_ENTITY_AND:
-    return mode != FP_MODE_INT ? 1 : 2;
+    return mode != FP_MODE_NONE && mode != FP_MODE_INT ? 1 : 2;
   case EPIPHANY_MSW_ENTITY_OR:
     return mode == FP_MODE_INT ? 1 : 2;
+  case EPIPHANY_MSW_ENTITY_CONFIG:
+    /* We must know/save config before we set it to something else.
+       Where we need the original value, we are fine with having it
+       just unchanged from the function start.
+       Because of the nature of the mode switching optimization,
+       a restore will be dominated by a clobber.  */
+    if (mode != FP_MODE_NONE && mode != FP_MODE_CALLER)
+      return 1;
+    /* A cpecial case are abnormal edges, which are deemed to clobber
+       the mode as well.  We need to pin this effect on a actually
+       dominating insn, and one where the frame can be accessed, too, in
+       case the pseudo used to save CONFIG doesn't get a hard register.  */
+    if (CALL_P (insn) && find_reg_note (insn, REG_EH_REGION, NULL_RTX))
+      return 1;
+    return 2;
   case EPIPHANY_MSW_ENTITY_ROUND_KNOWN:
     if (recog_memoized (insn) == CODE_FOR_set_fp_mode)
       mode = (enum attr_fp_mode) epiphany_mode_after (entity, mode, insn);
@@ -2396,6 +2380,10 @@  epiphany_mode_entry_exit (int entity, bo
       if (exit)
 	return normal_mode == FP_MODE_INT ? 1 : 2;
       return 0;
+    case EPIPHANY_MSW_ENTITY_CONFIG:
+      if (exit)
+	return 2;
+      return normal_mode == FP_MODE_CALLER ? 0 : 1;
     case EPIPHANY_MSW_ENTITY_ROUND_UNKNOWN:
       if (normal_mode == FP_MODE_ROUND_NEAREST
 	  || normal_mode == FP_MODE_ROUND_TRUNC)
@@ -2422,6 +2410,18 @@  epiphany_mode_after (int entity, int las
 	return 0;
       return last_mode;
     }
+  /* If there is an abnormal edge, we don't want the config register to
+     be 'saved' again at the destination.
+     The frame pointer adjustment is inside a PARALLEL because of the
+     flags clobber.  */
+  if (entity == EPIPHANY_MSW_ENTITY_CONFIG && NONJUMP_INSN_P (insn)
+      && GET_CODE (PATTERN (insn)) == PARALLEL
+      && GET_CODE (XVECEXP (PATTERN (insn), 0, 0)) == SET
+      && SET_DEST (XVECEXP (PATTERN (insn), 0, 0)) == frame_pointer_rtx)
+    {
+      gcc_assert (cfun->has_nonlocal_label);
+      return 1;
+    }
   if (recog_memoized (insn) < 0)
     return last_mode;
   if (get_attr_fp_mode (insn) == FP_MODE_ROUND_UNKNOWN
@@ -2475,12 +2475,25 @@  emit_set_fp_mode (int entity, int mode,
 	emit_move_insn (MACHINE_FUNCTION (cfun)->or_mask, GEN_INT(0x00080000));
       return;
     }
+  else if (entity == EPIPHANY_MSW_ENTITY_CONFIG)
+    {
+      /* Mode switching optimization is done after emit_initial_value_sets,
+	 so we have to take care of CONFIG_REGNUM here.  */
+      gcc_assert (mode >= 0 && mode <= 2);
+      rtx save = get_hard_reg_initial_val (SImode, CONFIG_REGNUM);
+      if (mode == 1)
+	emit_insn (gen_save_config (save));
+      return;
+    }
   fp_mode = (enum attr_fp_mode) mode;
   src = NULL_RTX;
 
   switch (fp_mode)
     {
       case FP_MODE_CALLER:
+	/* The EPIPHANY_MSW_ENTITY_CONFIG processing must come later
+	   so that the config save gets inserted before the first use.  */
+	gcc_assert (entity > EPIPHANY_MSW_ENTITY_CONFIG);
 	src = get_hard_reg_initial_val (SImode, CONFIG_REGNUM);
 	mask = MACHINE_FUNCTION (cfun)->and_mask;
 	break;
Index: config/epiphany/epiphany.h
===================================================================
--- config/epiphany/epiphany.h	(revision 198806)
+++ config/epiphany/epiphany.h	(working copy)
@@ -896,7 +896,8 @@  #define OPTIMIZE_MODE_SWITCHING(ENTITY)
    finally an entity that runs in a second mode switching pass to
    resolve FP_MODE_ROUND_UNKNOWN.  */
 #define NUM_MODES_FOR_MODE_SWITCHING \
-  { 2, 2, FP_MODE_NONE, FP_MODE_NONE, FP_MODE_NONE, FP_MODE_NONE, FP_MODE_NONE }
+  { 2, 2, 2, \
+    FP_MODE_NONE, FP_MODE_NONE, FP_MODE_NONE, FP_MODE_NONE, FP_MODE_NONE }
 
 #define MODE_NEEDED(ENTITY, INSN) epiphany_mode_needed((ENTITY), (INSN))
 
@@ -918,11 +919,13 @@  enum
 {
   EPIPHANY_MSW_ENTITY_AND,
   EPIPHANY_MSW_ENTITY_OR,
+  EPIPHANY_MSW_ENTITY_CONFIG, /* 1 means config is known or saved.  */
   EPIPHANY_MSW_ENTITY_NEAREST,
   EPIPHANY_MSW_ENTITY_TRUNC,
   EPIPHANY_MSW_ENTITY_ROUND_UNKNOWN,
   EPIPHANY_MSW_ENTITY_ROUND_KNOWN,
-  EPIPHANY_MSW_ENTITY_FPU_OMNIBUS
+  EPIPHANY_MSW_ENTITY_FPU_OMNIBUS,
+  EPIPHANY_MSW_ENTITY_NUM
 };
 
 extern int epiphany_normal_fp_rounding;
Index: config/epiphany/epiphany.md
===================================================================
--- config/epiphany/epiphany.md	(revision 198806)
+++ config/epiphany/epiphany.md	(working copy)
@@ -1448,6 +1448,16 @@  (define_insn "*movcc_i"
   [(set_attr "type" "flow")
    (set_attr "length" "20,4")])
 
+(define_insn_and_split "save_config"
+  [(set (match_operand:SI 0 "gpr_operand" "=r") (reg:SI CONFIG_REGNUM))
+   (use (reg:SI FP_NEAREST_REGNUM))
+   (use (reg:SI FP_TRUNCATE_REGNUM))
+   (use (reg:SI FP_ANYFP_REGNUM))]
+  ""
+  "#"
+  "reload_completed"
+  [(set (match_dup 0) (reg:SI CONFIG_REGNUM))])
+
 (define_insn_and_split "set_fp_mode"
   [(set (reg:SI FP_NEAREST_REGNUM)
 	(match_operand:SI 0 "set_fp_mode_operand" "rCfm"))