[AArch64] Backport PR62308 to 4.9

Index: gcc/ira-conflicts.c
===================================================================
--- gcc/ira-conflicts.c	(revision 215706)
+++ gcc/ira-conflicts.c	(revision 215707)
@@ -774,6 +774,27 @@ 
 				temp_hard_reg_set);
 	    }
 
+	  /* Now we deal with paradoxical subreg cases where certain registers
+	     cannot be accessed in the widest mode.  */
+	  enum machine_mode outer_mode = ALLOCNO_WMODE (a);
+	  enum machine_mode inner_mode = ALLOCNO_MODE (a);
+	  if (GET_MODE_SIZE (outer_mode) > GET_MODE_SIZE (inner_mode))
+	    {
+	      enum reg_class aclass = ALLOCNO_CLASS (a);
+	      for (int j = ira_class_hard_regs_num[aclass] - 1; j >= 0; --j)
+		{
+		   int inner_regno = ira_class_hard_regs[aclass][j];
+		   int outer_regno = simplify_subreg_regno (inner_regno,
+							    inner_mode, 0,
+							    outer_mode);
+		   if (outer_regno < 0
+		       || !in_hard_reg_set_p (reg_class_contents[aclass],
+					      outer_mode, outer_regno))
+		     SET_HARD_REG_BIT (OBJECT_CONFLICT_HARD_REGS (obj),
+				       inner_regno);
+		}
+	    }
+
 	  if (ALLOCNO_CALLS_CROSSED_NUM (a) != 0)
 	    {
 	      int regno;
Index: gcc/ChangeLog
===================================================================
--- gcc/ChangeLog	(revision 215706)
+++ gcc/ChangeLog	(revision 215707)
@@ -1,3 +1,11 @@ 
+2014-09-30  David Sherwood  <david.sherwood@arm.com>
+
+	* ira-int.h (ira_allocno): Add "wmode" field.
+	* ira-build.c (create_insn_allocnos): Add new "parent" function
+	parameter.
+	* ira-conflicts.c (ira_build_conflicts): Add conflicts for registers
+	that cannot be accessed in wmode.
+
 2014-09-30  Markus Trippelsdorf  <markus@trippelsdorf.de>
 
 	* data-streamer.c (bp_unpack_var_len_int): Avoid signed
Index: gcc/ira-int.h
===================================================================
--- gcc/ira-int.h	(revision 215706)
+++ gcc/ira-int.h	(revision 215707)
@@ -283,6 +283,9 @@ 
   /* Mode of the allocno which is the mode of the corresponding
      pseudo-register.  */
   ENUM_BITFIELD (machine_mode) mode : 8;
+  /* Widest mode of the allocno which in at least one case could be
+     for paradoxical subregs where wmode > mode.  */
+  ENUM_BITFIELD (machine_mode) wmode : 8;
   /* Register class which should be used for allocation for given
      allocno.  NO_REGS means that we should use memory.  */
   ENUM_BITFIELD (reg_class) aclass : 16;
@@ -315,7 +318,7 @@ 
      number (0, ...) - 2.  Value -1 is used for allocnos spilled by the
      reload (at this point pseudo-register has only one allocno) which
      did not get stack slot yet.  */
-  short int hard_regno;
+  int hard_regno : 16;
   /* Allocnos with the same regno are linked by the following member.
      Allocnos corresponding to inner loops are first in the list (it
      corresponds to depth-first traverse of the loops).  */
@@ -436,6 +439,7 @@ 
 #define ALLOCNO_BAD_SPILL_P(A) ((A)->bad_spill_p)
 #define ALLOCNO_ASSIGNED_P(A) ((A)->assigned_p)
 #define ALLOCNO_MODE(A) ((A)->mode)
+#define ALLOCNO_WMODE(A) ((A)->wmode)
 #define ALLOCNO_PREFS(A) ((A)->allocno_prefs)
 #define ALLOCNO_COPIES(A) ((A)->allocno_copies)
 #define ALLOCNO_HARD_REG_COSTS(A) ((A)->hard_reg_costs)
Index: gcc/ira-build.c
===================================================================
--- gcc/ira-build.c	(revision 215706)
+++ gcc/ira-build.c	(revision 215707)
@@ -524,6 +524,7 @@ 
   ALLOCNO_BAD_SPILL_P (a) = false;
   ALLOCNO_ASSIGNED_P (a) = false;
   ALLOCNO_MODE (a) = (regno < 0 ? VOIDmode : PSEUDO_REGNO_MODE (regno));
+  ALLOCNO_WMODE (a) = ALLOCNO_MODE (a);
   ALLOCNO_PREFS (a) = NULL;
   ALLOCNO_COPIES (a) = NULL;
   ALLOCNO_HARD_REG_COSTS (a) = NULL;
@@ -893,6 +894,7 @@ 
   parent = ALLOCNO_LOOP_TREE_NODE (a)->parent;
   cap = ira_create_allocno (ALLOCNO_REGNO (a), true, parent);
   ALLOCNO_MODE (cap) = ALLOCNO_MODE (a);
+  ALLOCNO_WMODE (cap) = ALLOCNO_WMODE (a);
   aclass = ALLOCNO_CLASS (a);
   ira_set_allocno_class (cap, aclass);
   ira_create_allocno_objects (cap);
@@ -1859,9 +1861,9 @@ 
 
 /* This recursive function creates allocnos corresponding to
    pseudo-registers containing in X.  True OUTPUT_P means that X is
-   a lvalue.  */
+   an lvalue.  PARENT corresponds to the parent expression of X.  */
 static void
-create_insn_allocnos (rtx x, bool output_p)
+create_insn_allocnos (rtx x, rtx outer, bool output_p)
 {
   int i, j;
   const char *fmt;
@@ -1876,7 +1878,15 @@ 
 	  ira_allocno_t a;
 
 	  if ((a = ira_curr_regno_allocno_map[regno]) == NULL)
-	    a = ira_create_allocno (regno, false, ira_curr_loop_tree_node);
+	    {
+	      a = ira_create_allocno (regno, false, ira_curr_loop_tree_node);
+	      if (outer != NULL && GET_CODE (outer) == SUBREG)
+		{
+		  enum machine_mode wmode = GET_MODE (outer);
+		  if (GET_MODE_SIZE (wmode) > GET_MODE_SIZE (ALLOCNO_WMODE (a)))
+		    ALLOCNO_WMODE (a) = wmode;
+		}
+	    }
 
 	  ALLOCNO_NREFS (a)++;
 	  ALLOCNO_FREQ (a) += REG_FREQ_FROM_BB (curr_bb);
@@ -1887,25 +1897,25 @@ 
     }
   else if (code == SET)
     {
-      create_insn_allocnos (SET_DEST (x), true);
-      create_insn_allocnos (SET_SRC (x), false);
+      create_insn_allocnos (SET_DEST (x), NULL, true);
+      create_insn_allocnos (SET_SRC (x), NULL, false);
       return;
     }
   else if (code == CLOBBER)
     {
-      create_insn_allocnos (XEXP (x, 0), true);
+      create_insn_allocnos (XEXP (x, 0), NULL, true);
       return;
     }
   else if (code == MEM)
     {
-      create_insn_allocnos (XEXP (x, 0), false);
+      create_insn_allocnos (XEXP (x, 0), NULL, false);
       return;
     }
   else if (code == PRE_DEC || code == POST_DEC || code == PRE_INC ||
 	   code == POST_INC || code == POST_MODIFY || code == PRE_MODIFY)
     {
-      create_insn_allocnos (XEXP (x, 0), true);
-      create_insn_allocnos (XEXP (x, 0), false);
+      create_insn_allocnos (XEXP (x, 0), NULL, true);
+      create_insn_allocnos (XEXP (x, 0), NULL, false);
       return;
     }
 
@@ -1913,10 +1923,10 @@ 
   for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
     {
       if (fmt[i] == 'e')
-	create_insn_allocnos (XEXP (x, i), output_p);
+	create_insn_allocnos (XEXP (x, i), x, output_p);
       else if (fmt[i] == 'E')
 	for (j = 0; j < XVECLEN (x, i); j++)
-	  create_insn_allocnos (XVECEXP (x, i, j), output_p);
+	  create_insn_allocnos (XVECEXP (x, i, j), x, output_p);
     }
 }
 
@@ -1935,7 +1945,7 @@ 
   ira_assert (bb != NULL);
   FOR_BB_INSNS_REVERSE (bb, insn)
     if (NONDEBUG_INSN_P (insn))
-      create_insn_allocnos (PATTERN (insn), false);
+      create_insn_allocnos (PATTERN (insn), NULL, false);
   /* It might be a allocno living through from one subloop to
      another.  */
   EXECUTE_IF_SET_IN_REG_SET (df_get_live_in (bb), FIRST_PSEUDO_REGISTER, i, bi)