re PR rtl-optimization/55342 ([LRA,x86] Non-optimal code for simple loop with LRA)

2013-07-05  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/55342
	* lra-int.h (lra_subreg_reload_pseudos): New.
	* lra.c: Add undoing optional reloads to the block diagram.
	(lra_subreg_reload_pseudos): New.
	(lra_optional_reload_pseudos): Change comments.
	(lra): Init and clear lra_subreg_reload_pseudos.  Clear
	lra_optional_reload_pseudos after undo transformations.
	* lra-assigns.c (pseudo_prefix_title): New.
	(lra_setup_reg_renumber): Use it.
	(spill_for): Ditto.  Check subreg reload pseudos too.
	(assign_by_spills): Consider subreg reload pseudos too.
	* lra-constraints.c (simplify_operand_subreg): Use
	lra_subreg_reload_pseudos instead of lra_optional_reload_pseudos.
	(curr_insn_transform): Recognize and do optional reloads.
	(undo_optional_reloads): New.
	(lra_undo_inheritance): Call undo_optional_reloads.

2013-07-05  Vladimir Makarov  <vmakarov@redhat.com>

	PR rtl-optimization/55342
	* gcc.target/i386/pr55342.c: New.

From-SVN: r200723

gcc/ChangeLog

+2013-07-05  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/55342
+	* lra-int.h (lra_subreg_reload_pseudos): New.
+	* lra.c: Add undoing optional reloads to the block diagram.
+	(lra_subreg_reload_pseudos): New.
+	(lra_optional_reload_pseudos): Change comments.
+	(lra): Init and clear lra_subreg_reload_pseudos.  Clear
+	lra_optional_reload_pseudos after undo transformations.
+	* lra-assigns.c (pseudo_prefix_title): New.
+	(lra_setup_reg_renumber): Use it.
+	(spill_for): Ditto.  Check subreg reload pseudos too.
+	(assign_by_spills): Consider subreg reload pseudos too.
+	* lra-constraints.c (simplify_operand_subreg): Use
+	lra_subreg_reload_pseudos instead of lra_optional_reload_pseudos.
+	(curr_insn_transform): Recognize and do optional reloads.
+	(undo_optional_reloads): New.
+	(lra_undo_inheritance): Call undo_optional_reloads.
+
 2013-07-05  Thomas Quinot  <quinot@adacore.com>
 
 	* tree-complex.c (expand_complex_operations_1): Fix typo.

gcc/lra-assigns.c

@@ -672,6 +672,19 @@ update_hard_regno_preference (int regno, int hard_regno, int div)
     }
 }
 
+/* Return prefix title for pseudo REGNO.  */
+static const char *
+pseudo_prefix_title (int regno)
+{
+  return
+    (regno < lra_constraint_new_regno_start ? ""
+     : bitmap_bit_p (&lra_inheritance_pseudos, regno) ? "inheritance "
+     : bitmap_bit_p (&lra_split_regs, regno) ? "split "
+     : bitmap_bit_p (&lra_optional_reload_pseudos, regno) ? "optional reload "
+     : bitmap_bit_p (&lra_subreg_reload_pseudos, regno) ? "subreg reload "
+     : "reload ");
+}
+
 /* Update REG_RENUMBER and other pseudo preferences by assignment of
    HARD_REGNO to pseudo REGNO and print about it if PRINT_P.  */
 void
@@ -692,13 +705,7 @@ lra_setup_reg_renumber (int regno, int hard_regno, bool print_p)
       lra_hard_reg_usage[hr + i] += lra_reg_info[regno].freq;
   if (print_p && lra_dump_file != NULL)
     fprintf (lra_dump_file, "	   Assign %d to %sr%d (freq=%d)\n",
-	     reg_renumber[regno],
-	     regno < lra_constraint_new_regno_start
-	     ? ""
-	     : bitmap_bit_p (&lra_inheritance_pseudos, regno) ? "inheritance "
-	     : bitmap_bit_p (&lra_split_regs, regno) ? "split "
-	     : bitmap_bit_p (&lra_optional_reload_pseudos, regno)
-	     ? "optional reload ": "reload ",
+	     reg_renumber[regno], pseudo_prefix_title (regno),
 	     regno, lra_reg_info[regno].freq);
   if (hard_regno >= 0)
     {
@@ -844,6 +851,7 @@ spill_for (int regno, bitmap spilled_pseudo_bitmap)
 	if ((int) spill_regno >= lra_constraint_new_regno_start
 	    && ! bitmap_bit_p (&lra_inheritance_pseudos, spill_regno)
 	    && ! bitmap_bit_p (&lra_split_regs, spill_regno)
+	    && ! bitmap_bit_p (&lra_subreg_reload_pseudos, spill_regno)
 	    && ! bitmap_bit_p (&lra_optional_reload_pseudos, spill_regno))
 	  goto fail;
       insn_pseudos_num = 0;
@@ -953,14 +961,7 @@ spill_for (int regno, bitmap spilled_pseudo_bitmap)
     {
       if (lra_dump_file != NULL)
 	fprintf (lra_dump_file, "      Spill %sr%d(hr=%d, freq=%d) for r%d\n",
-		 ((int) spill_regno < lra_constraint_new_regno_start
-		  ? ""
-		  : bitmap_bit_p (&lra_inheritance_pseudos, spill_regno)
-		  ? "inheritance "
-		  : bitmap_bit_p (&lra_split_regs, spill_regno)
-		  ? "split "
-		  : bitmap_bit_p (&lra_optional_reload_pseudos, spill_regno)
-		  ? "optional reload " : "reload "),
+		 pseudo_prefix_title (spill_regno),
 		 spill_regno, reg_renumber[spill_regno],
 		 lra_reg_info[spill_regno].freq, regno);
       update_lives (spill_regno, true);
@@ -1176,6 +1177,7 @@ assign_by_spills (void)
   bitmap_initialize (&changed_insns, &reg_obstack);
   bitmap_initialize (&non_reload_pseudos, &reg_obstack);
   bitmap_ior (&non_reload_pseudos, &lra_inheritance_pseudos, &lra_split_regs);
+  bitmap_ior_into (&non_reload_pseudos, &lra_subreg_reload_pseudos);
   bitmap_ior_into (&non_reload_pseudos, &lra_optional_reload_pseudos);
   for (iter = 0; iter <= 1; iter++)
     {
@@ -1350,6 +1352,7 @@ assign_by_spills (void)
 		 && lra_reg_info[i].restore_regno >= 0)
 	     || (bitmap_bit_p (&lra_split_regs, i)
 		 && lra_reg_info[i].restore_regno >= 0)
+	     || bitmap_bit_p (&lra_subreg_reload_pseudos, i)
 	     || bitmap_bit_p (&lra_optional_reload_pseudos, i))
 	    && reg_renumber[i] < 0 && lra_reg_info[i].nrefs != 0
 	    && regno_allocno_class_array[i] != NO_REGS)

gcc/lra-constraints.c

@@ -1228,7 +1228,7 @@ simplify_operand_subreg (int nop, enum machine_mode reg_mode)
       if (get_reload_reg (curr_static_id->operand[nop].type, reg_mode, reg,
 			  rclass, "subreg reg", &new_reg))
 	{
-	  bitmap_set_bit (&lra_optional_reload_pseudos, REGNO (new_reg));
+	  bitmap_set_bit (&lra_subreg_reload_pseudos, REGNO (new_reg));
 	  if (type != OP_OUT
 	      || GET_MODE_SIZE (GET_MODE (reg)) > GET_MODE_SIZE (mode))
 	    {
@@ -3183,6 +3183,8 @@ curr_insn_transform (void)
 
   for (i = 0; i < n_operands; i++)
     {
+      int regno;
+      bool optional_p = false;
       rtx old, new_reg;
       rtx op = *curr_id->operand_loc[i];
 
@@ -3205,6 +3207,21 @@ curr_insn_transform (void)
 		   current one.  */
 		reg_renumber[regno] = -1;
 	    }
+	  /* We can do an optional reload.  If the pseudo got a hard
+	     reg, we might improve the code through inheritance.  If
+	     it does not get a hard register we coalesce memory/memory
+	     moves later.  Ignore move insns to avoid cycling.  */
+	  if (! lra_simple_p
+	      && lra_undo_inheritance_iter < LRA_MAX_INHERITANCE_PASSES
+	      && goal_alt[i] != NO_REGS && REG_P (op)
+	      && (regno = REGNO (op)) >= FIRST_PSEUDO_REGISTER
+	      && reg_renumber[regno] < 0
+	      && (curr_insn_set == NULL_RTX
+		  || !(REG_P (SET_SRC (curr_insn_set))
+		       || MEM_P (SET_SRC (curr_insn_set))
+		       || GET_CODE (SET_SRC (curr_insn_set)) == SUBREG)))
+	    optional_p = true;
+	  else
 	    continue;
 	}
 
@@ -3328,6 +3345,21 @@ curr_insn_transform (void)
 	/* We must generate code in any case when function
 	   process_alt_operands decides that it is possible.  */
 	gcc_unreachable ();
+      if (optional_p)
+	{
+	  lra_assert (REG_P (op));
+	  regno = REGNO (op);
+	  op = *curr_id->operand_loc[i]; /* Substitution.  */
+	  if (GET_CODE (op) == SUBREG)
+	    op = SUBREG_REG (op);
+	  gcc_assert (REG_P (op) && (int) REGNO (op) >= new_regno_start);
+	  bitmap_set_bit (&lra_optional_reload_pseudos, REGNO (op));
+	  lra_reg_info[REGNO (op)].restore_regno = regno;
+	  if (lra_dump_file != NULL)
+	    fprintf (lra_dump_file,
+		     "      Making reload reg %d for reg %d optional\n",
+		     REGNO (op), regno);
+	}
     }
   if (before != NULL_RTX || after != NULL_RTX
       || max_regno_before != max_reg_num ())
@@ -5273,6 +5305,100 @@ remove_inheritance_pseudos (bitmap remove_pseudos)
   return change_p;
 }
 
+/* If optional reload pseudos failed to get a hard register or was not
+   inherited, it is better to remove optional reloads.  We do this
+   transformation after undoing inheritance to figure out necessity to
+   remove optional reloads easier.  Return true if we do any
+   change.  */
+static bool
+undo_optional_reloads (void)
+{
+  bool change_p;
+  unsigned int regno, uid;
+  bitmap_iterator bi, bi2;
+  rtx insn, set, src, dest;
+  bitmap_head removed_optional_reload_pseudos, insn_bitmap;
+
+  bitmap_initialize (&removed_optional_reload_pseudos, &reg_obstack);
+  bitmap_copy (&removed_optional_reload_pseudos, &lra_optional_reload_pseudos);
+  EXECUTE_IF_SET_IN_BITMAP (&lra_optional_reload_pseudos, 0, regno, bi)
+    if (reg_renumber[regno] >= 0)
+      EXECUTE_IF_SET_IN_BITMAP (&lra_reg_info[regno].insn_bitmap, 0, uid, bi2)
+	{
+	  insn = lra_insn_recog_data[uid]->insn;
+	  if ((set = single_set (insn)) == NULL_RTX)
+	    continue;
+	  src = SET_SRC (set);
+	  dest = SET_DEST (set);
+	  if (! REG_P (src) || ! REG_P (dest))
+	    continue;
+	  if ((REGNO (src) == regno
+	       && lra_reg_info[regno].restore_regno != (int) REGNO (dest))
+	      || (REGNO (dest) == regno
+		  && lra_reg_info[regno].restore_regno != (int) REGNO (src)))
+	    {
+	      /* Optional reload was inherited.  Keep it.  */
+	      bitmap_clear_bit (&removed_optional_reload_pseudos, regno);
+	      if (lra_dump_file != NULL)
+		fprintf (lra_dump_file, "Keep optional reload reg %d\n", regno);
+	    }
+	}
+  change_p = ! bitmap_empty_p (&removed_optional_reload_pseudos);
+  bitmap_initialize (&insn_bitmap, &reg_obstack);
+  EXECUTE_IF_SET_IN_BITMAP (&removed_optional_reload_pseudos, 0, regno, bi)
+    {
+      if (lra_dump_file != NULL)
+	fprintf (lra_dump_file, "Remove optional reload reg %d\n", regno);
+      bitmap_copy (&insn_bitmap, &lra_reg_info[regno].insn_bitmap);
+      EXECUTE_IF_SET_IN_BITMAP (&insn_bitmap, 0, uid, bi2)
+	{
+	  insn = lra_insn_recog_data[uid]->insn;
+	  if ((set = single_set (insn)) != NULL_RTX)
+	    {
+	      src = SET_SRC (set);
+	      dest = SET_DEST (set);
+	      if (REG_P (src) && REG_P (dest)
+		  && ((REGNO (src) == regno
+		       && (lra_reg_info[regno].restore_regno
+			   == (int) REGNO (dest)))
+		      || (REGNO (dest) == regno
+			  && (lra_reg_info[regno].restore_regno
+			      == (int) REGNO (src)))))
+		{
+		  if (lra_dump_file != NULL)
+		    {
+		      fprintf (lra_dump_file, "  Deleting move %u\n",
+			       INSN_UID (insn));
+		      dump_insn_slim (lra_dump_file, insn);
+		    }
+		  lra_set_insn_deleted (insn);
+		  continue;
+		}
+	      /* We should not worry about generation memory-memory
+		 moves here as if the corresponding inheritance did
+		 not work (inheritance pseudo did not get a hard reg),
+		 we remove the inheritance pseudo and the optional
+		 reload.  */
+	    }
+	  substitute_pseudo (&insn, regno,
+			     regno_reg_rtx[lra_reg_info[regno].restore_regno]);
+	  lra_update_insn_regno_info (insn);
+	  if (lra_dump_file != NULL)
+	    {
+	      fprintf (lra_dump_file,
+		       "  Restoring original insn:\n");
+	      dump_insn_slim (lra_dump_file, insn);
+	    }
+	}
+    }
+  /* Clear restore_regnos.  */
+  EXECUTE_IF_SET_IN_BITMAP (&lra_optional_reload_pseudos, 0, regno, bi)
+    lra_reg_info[regno].restore_regno = -1;
+  bitmap_clear (&insn_bitmap);
+  bitmap_clear (&removed_optional_reload_pseudos);
+  return change_p;
+}
+
 /* Entry function for undoing inheritance/split transformation.	 Return true
    if we did any RTL change in this pass.  */
 bool
@@ -5335,5 +5461,6 @@ lra_undo_inheritance (void)
     lra_reg_info[regno].restore_regno = -1;
   EXECUTE_IF_SET_IN_BITMAP (&lra_split_regs, 0, regno, bi)
     lra_reg_info[regno].restore_regno = -1;
+  change_p = undo_optional_reloads () || change_p;
   return change_p;
 }

gcc/lra-int.h

@@ -321,6 +321,7 @@ extern int lra_new_regno_start;
 extern int lra_constraint_new_regno_start;
 extern bitmap_head lra_inheritance_pseudos;
 extern bitmap_head lra_split_regs;
+extern bitmap_head lra_subreg_reload_pseudos;
 extern bitmap_head lra_optional_reload_pseudos;
 extern int lra_constraint_new_insn_uid_start;
 

gcc/lra.c

@@ -43,13 +43,13 @@ along with GCC; see the file COPYING3.	If not see
 
    Here is block diagram of LRA passes:
 
-                                ---------------------
-           ---------------     | Undo inheritance    |     ---------------
-          | Memory-memory |    | for spilled pseudos)|    | New (and old) |
-          | move coalesce |<---| and splits (for     |<-- |   pseudos     |
-           ---------------     | pseudos got the     |    |  assignment   |
-  Start           |            |  same  hard regs)   |     ---------------
-    |             |             ---------------------               ^
+                                ------------------------
+           ---------------     | Undo inheritance for   |     ---------------
+          | Memory-memory |    | spilled pseudos,       |    | New (and old) |
+          | move coalesce |<---| splits for pseudos got |<-- |   pseudos     |
+           ---------------     | the same hard regs,    |    |  assignment   |
+  Start           |            | and optional reloads   |     ---------------
+    |             |             ------------------------            ^
     V             |              ----------------                   |
  -----------      V             | Update virtual |                  |
 |  Remove   |----> ------------>|    register    |                  |
@@ -2187,10 +2187,16 @@ bitmap_head lra_inheritance_pseudos;
 /* Split regnos before the new spill pass.  */
 bitmap_head lra_split_regs;
 
-/* Reload pseudo regnos before the new assign pass which still can be
-   spilled after the assinment pass.  */
+/* Reload pseudo regnos before the new assignmnet pass which still can
+   be spilled after the assinment pass as memory is also accepted in
+   insns for the reload pseudos.  */
 bitmap_head lra_optional_reload_pseudos;
 
+/* Pseudo regnos used for subreg reloads before the new assignment
+   pass.  Such pseudos still can be spilled after the assinment
+   pass.  */
+bitmap_head lra_subreg_reload_pseudos;
+
 /* First UID of insns generated before a new spill pass.  */
 int lra_constraint_new_insn_uid_start;
 
@@ -2296,6 +2302,7 @@ lra (FILE *f)
   bitmap_initialize (&lra_inheritance_pseudos, &reg_obstack);
   bitmap_initialize (&lra_split_regs, &reg_obstack);
   bitmap_initialize (&lra_optional_reload_pseudos, &reg_obstack);
+  bitmap_initialize (&lra_subreg_reload_pseudos, &reg_obstack);
   live_p = false;
   if (get_frame_size () != 0 && crtl->stack_alignment_needed)
     /* If we have a stack frame, we must align it now.  The stack size
@@ -2356,8 +2363,9 @@ lra (FILE *f)
 	      if (! live_p)
 		lra_clear_live_ranges ();
 	    }
-	}
 	  bitmap_clear (&lra_optional_reload_pseudos);
+	}
+      bitmap_clear (&lra_subreg_reload_pseudos);
       bitmap_clear (&lra_inheritance_pseudos);
       bitmap_clear (&lra_split_regs);
       if (! lra_need_for_spills_p ())

gcc/testsuite/ChangeLog

+2013-07-05  Vladimir Makarov  <vmakarov@redhat.com>
+
+	PR rtl-optimization/55342
+	* gcc.target/i386/pr55342.c: New.
+
 2013-07-05  Marcus Shawcroft  <marcus.shawcroft@arm.com>
 
 	* gcc.dg/pr57518.c: Adjust scan-rtl-dump-not pattern.

gcc/testsuite/gcc.target/i386/pr55342.c

+/* PR rtl-optimization/55342 */
+/* { dg-do compile } */
+/* { dg-options "-O2" } */
+/* { dg-final { scan-assembler-not "notb" } } */
+
+
+void convert_image(unsigned char *in, unsigned char *out, int size) {
+    int i;
+    unsigned char * read = in,
+     * write = out;
+    for(i = 0; i < size; i++) {
+        unsigned char r = *read++;
+        unsigned char g = *read++;
+        unsigned char b = *read++;
+        unsigned char c, m, y, k, tmp;
+        c = 255 - r;
+        m = 255 - g;
+        y = 255 - b;
+	if (c < m)
+	  k = ((c) > (y)?(y):(c));
+	else
+          k = ((m) > (y)?(y):(m));
+        *write++ = c - k;
+        *write++ = m - k;
+        *write++ = y - k;
+        *write++ = k;
+    }
+}