lra-constraints.c (process_address): Add forward declaration.

	* lra-constraints.c (process_address): Add forward declaration.
	(simplify_operand_subreg): In the MEM case, if the adjusted memory
	reference is not sufficient aligned and the address was invalid,
	reload the address before reloading the original memory reference.
	Fix long lines and add a final return for the sake of clarity.

From-SVN: r243782

gcc/ChangeLog

+2016-12-18  Eric Botcazou  <ebotcazou@adacore.com>
+
+	* lra-constraints.c (process_address): Add forward declaration.
+	(simplify_operand_subreg): In the MEM case, if the adjusted memory
+	reference is not sufficient aligned and the address was invalid,
+	reload the address before reloading the original memory reference.
+	Fix long lines and add a final return for the sake of clarity.
+
 2016-12-17  Jakub Jelinek  <jakub@redhat.com>
 
 	PR sanitizer/78832

gcc/lra-constraints.c

@@ -1454,6 +1454,7 @@ insert_move_for_subreg (rtx_insn **before, rtx_insn **after, rtx origreg,
 }
 
 static int valid_address_p (machine_mode mode, rtx addr, addr_space_t as);
+static bool process_address (int, bool, rtx_insn **, rtx_insn **);
 
 /* Make reloads for subreg in operand NOP with internal subreg mode
    REG_MODE, add new reloads for further processing.  Return true if
@@ -1480,13 +1481,13 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
   type = curr_static_id->operand[nop].type;
   if (MEM_P (reg))
     {
-      rtx subst;
-
+      const bool addr_was_valid
+	= valid_address_p (innermode, XEXP (reg, 0), MEM_ADDR_SPACE (reg));
       alter_subreg (curr_id->operand_loc[nop], false);
-      subst = *curr_id->operand_loc[nop];
+      rtx subst = *curr_id->operand_loc[nop];
       lra_assert (MEM_P (subst));
-      if (! valid_address_p (innermode, XEXP (reg, 0),
-			     MEM_ADDR_SPACE (reg))
+
+      if (!addr_was_valid
 	  || valid_address_p (GET_MODE (subst), XEXP (subst, 0),
 			      MEM_ADDR_SPACE (subst))
 	  || ((get_constraint_type (lookup_constraint
@@ -1503,10 +1504,10 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
 						    ADDRESS, SCRATCH)][0]],
 				  MEM_ADDR_SPACE (subst))))
 	{
-	  /* If we change address for paradoxical subreg of memory, the
+	  /* If we change the address for a paradoxical subreg of memory, the
 	     address might violate the necessary alignment or the access might
-	     be slow.  So take this into consideration.  We should not worry
-	     about access beyond allocated memory for paradoxical memory
+	     be slow.  So take this into consideration.  We need not worry
+	     about accesses beyond allocated memory for paradoxical memory
 	     subregs as we don't substitute such equiv memory (see processing
 	     equivalences in function lra_constraints) and because for spilled
 	     pseudos we allocate stack memory enough for the biggest
@@ -1517,28 +1518,36 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
 		  && SLOW_UNALIGNED_ACCESS (innermode, MEM_ALIGN (reg))))
 	    return true;
 
+	  *curr_id->operand_loc[nop] = operand;
+
+	  /* But if the address was not valid, we cannot reload the MEM without
+	     reloading the address first.  */
+	  if (!addr_was_valid)
+	    process_address (nop, false, &before, &after);
+
 	  /* INNERMODE is fast, MODE slow.  Reload the mem in INNERMODE.  */
 	  enum reg_class rclass
 	    = (enum reg_class) targetm.preferred_reload_class (reg, ALL_REGS);
-	  if (get_reload_reg (curr_static_id->operand[nop].type, innermode, reg,
-			      rclass, TRUE, "slow mem", &new_reg))
+	  if (get_reload_reg (curr_static_id->operand[nop].type, innermode,
+			      reg, rclass, TRUE, "slow mem", &new_reg))
 	    {
 	      bool insert_before, insert_after;
 	      bitmap_set_bit (&lra_subreg_reload_pseudos, REGNO (new_reg));
 
 	      insert_before = (type != OP_OUT
-			       || GET_MODE_SIZE (innermode) > GET_MODE_SIZE (mode));
+			       || GET_MODE_SIZE (innermode)
+				    > GET_MODE_SIZE (mode));
 	      insert_after = type != OP_IN;
 	      insert_move_for_subreg (insert_before ? &before : NULL,
 				      insert_after ? &after : NULL,
 				      reg, new_reg);
 	    }
-	  *curr_id->operand_loc[nop] = operand;
 	  SUBREG_REG (operand) = new_reg;
 
 	  /* Convert to MODE.  */
 	  reg = operand;
-	  rclass = (enum reg_class) targetm.preferred_reload_class (reg, ALL_REGS);
+	  rclass
+	    = (enum reg_class) targetm.preferred_reload_class (reg, ALL_REGS);
 	  if (get_reload_reg (curr_static_id->operand[nop].type, mode, reg,
 			      rclass, TRUE, "slow mem", &new_reg))
 	    {
@@ -1561,6 +1570,7 @@ simplify_operand_subreg (int nop, machine_mode reg_mode)
 	 the memory.  Typical case is when the index scale should
 	 correspond the memory.  */
       *curr_id->operand_loc[nop] = operand;
+      return false;
     }
   else if (REG_P (reg) && REGNO (reg) < FIRST_PSEUDO_REGISTER)
     {