re PR rtl-optimization/52543 (lower-subreg.c: code bloat of 300%-400% for multi-word memory splits)

	PR rtl-optimization/52543
	* config/avr/avr.c (avr_mode_dependent_address_p): Return true for
	all non-generic address spaces.
	(TARGET_SECONDARY_RELOAD): New hook define to...
	(avr_secondary_reload): ...this new static function.
	* config/avr/avr.md (reload_in<mode>): New insns.
	Undo r185605 (mostly):
	* config/avr/avr-protos.h (avr_load_lpm): Remove.
	* config/avr/avr.c (avr_load_libgcc_p): Don't restrict to __flash loads.
	(avr_out_lpm): Also handle loads > 1 byte.
	(avr_load_lpm): Remove.
	(avr_find_unused_d_reg): New static function.
	(avr_out_lpm_no_lpmx): New static function.
	(adjust_insn_length): Remove ADJUST_LEN_LOAD_LPM.
	* config/avr/avr.md (unspec): Remove UNSPEC_LPM.
	(load_<mode>_libgcc): Use MEM instead of UNSPEC_LPM.
	(load_<mode>, load_<mode>_clobber): Remove.
	(mov<mode>): For multi-byte move from non-generic
	16-bit address spaces: Expand to *mov<mode> again.
	(load<mode>_libgcc): New expander.
	(split-lpmx): Remove split.

From-SVN: r191820

gcc/ChangeLog

+2012-09-28  Georg-Johann Lay  <avr@gjlay.de>
+
+	PR rtl-optimization/52543
+	* config/avr/avr.c (avr_mode_dependent_address_p): Return true for
+	all non-generic address spaces.
+	(TARGET_SECONDARY_RELOAD): New hook define to...
+	(avr_secondary_reload): ...this new static function.
+	* config/avr/avr.md (reload_in<mode>): New insns.
+
+	Undo r185605 (mostly):
+	* config/avr/avr-protos.h (avr_load_lpm): Remove.
+	* config/avr/avr.c (avr_load_libgcc_p): Don't restrict to __flash loads.
+	(avr_out_lpm): Also handle loads > 1 byte.
+	(avr_load_lpm): Remove.
+	(avr_find_unused_d_reg): New static function.
+	(avr_out_lpm_no_lpmx): New static function.
+	(adjust_insn_length): Remove ADJUST_LEN_LOAD_LPM.
+	* config/avr/avr.md (unspec): Remove UNSPEC_LPM.
+	(load_<mode>_libgcc): Use MEM instead of UNSPEC_LPM.
+	(load_<mode>, load_<mode>_clobber): Remove.
+	(mov<mode>): For multi-byte move from non-generic
+	16-bit address spaces: Expand to *mov<mode> again.
+	(load<mode>_libgcc): New expander.
+	(split-lpmx): Remove split.
+
 2012-09-27  Dehao Chen  <dehao@google.com>
 
 	* tree.h (tree_constructor): Remove IS_UNKNOWN_LOCATION.

gcc/config/avr/avr-protos.h

@@ -75,8 +75,6 @@ extern const char *avr_out_ashlpsi3 (rtx, rtx*, int*);
 extern const char *avr_out_ashrpsi3 (rtx, rtx*, int*);
 extern const char *avr_out_lshrpsi3 (rtx, rtx*, int*);
 
-extern const char* avr_load_lpm (rtx, rtx*, int*);
-
 extern bool avr_rotate_bytes (rtx operands[]);
 
 extern const char* avr_out_fract (rtx, rtx[], bool, int*);

gcc/config/avr/avr.c

@@ -1625,17 +1625,17 @@ avr_cannot_modify_jumps_p (void)
 
 /* Implement `TARGET_MODE_DEPENDENT_ADDRESS_P'.  */
 
-/* FIXME:  PSImode addresses are not mode-dependent in themselves.
-      This hook just serves to hack around PR rtl-optimization/52543 by
-      claiming that PSImode addresses (which are used for the 24-bit
-      address space __memx) were mode-dependent so that lower-subreg.s
-      will skip these addresses.  See also the similar FIXME comment along
-      with mov<mode> expanders in avr.md.  */
-
 static bool
-avr_mode_dependent_address_p (const_rtx addr, addr_space_t as ATTRIBUTE_UNUSED)
+avr_mode_dependent_address_p (const_rtx addr ATTRIBUTE_UNUSED, addr_space_t as)
 {
-  return GET_MODE (addr) != Pmode;
+  /* FIXME:  Non-generic addresses are not mode-dependent in themselves.
+       This hook just serves to hack around PR rtl-optimization/52543 by
+       claiming that non-generic addresses were mode-dependent so that
+       lower-subreg.c will skip these addresses.  lower-subreg.c sets up fake
+       RTXes to probe SET and MEM costs and assumes that MEM is always in the
+       generic address space which is not true.  */
+
+  return !ADDR_SPACE_GENERIC_P (as);
 }
 
 
@@ -1865,6 +1865,50 @@ avr_legitimize_reload_address (rtx *px, enum machine_mode mode,
 }
 
 
+/* Implement `TARGET_SECONDARY_RELOAD' */
+
+static reg_class_t
+avr_secondary_reload (bool in_p, rtx x,
+                      reg_class_t reload_class ATTRIBUTE_UNUSED,
+                      enum machine_mode mode, secondary_reload_info *sri)
+{
+  if (in_p
+      && MEM_P (x)
+      && !ADDR_SPACE_GENERIC_P (MEM_ADDR_SPACE (x))
+      && ADDR_SPACE_MEMX != MEM_ADDR_SPACE (x))
+    {
+      /* For the non-generic 16-bit spaces we need a d-class scratch.  */
+
+      switch (mode)
+        {
+        default:
+          gcc_unreachable();
+
+        case QImode:  sri->icode = CODE_FOR_reload_inqi; break;
+        case QQmode:  sri->icode = CODE_FOR_reload_inqq; break;
+        case UQQmode: sri->icode = CODE_FOR_reload_inuqq; break;
+
+        case HImode:  sri->icode = CODE_FOR_reload_inhi; break;
+        case HQmode:  sri->icode = CODE_FOR_reload_inhq; break;
+        case HAmode:  sri->icode = CODE_FOR_reload_inha; break;
+        case UHQmode: sri->icode = CODE_FOR_reload_inuhq; break;
+        case UHAmode: sri->icode = CODE_FOR_reload_inuha; break;
+
+        case PSImode: sri->icode = CODE_FOR_reload_inpsi; break;
+
+        case SImode:  sri->icode = CODE_FOR_reload_insi; break;
+        case SFmode:  sri->icode = CODE_FOR_reload_insf; break;
+        case SQmode:  sri->icode = CODE_FOR_reload_insq; break;
+        case SAmode:  sri->icode = CODE_FOR_reload_insa; break;
+        case USQmode: sri->icode = CODE_FOR_reload_inusq; break;
+        case USAmode: sri->icode = CODE_FOR_reload_inusa; break;
+        }
+    }
+
+  return NO_REGS;
+}
+
+
 /* Helper function to print assembler resp. track instruction
    sequence lengths.  Always return "".
    
@@ -2655,8 +2699,7 @@ avr_load_libgcc_p (rtx op)
         
   return (n_bytes > 2
           && !AVR_HAVE_LPMX
-          && MEM_P (op)
-          && MEM_ADDR_SPACE (op) == ADDR_SPACE_FLASH);
+          && avr_mem_flash_p (op));
 }
 
 /* Return true if a value of mode MODE is read by __xload_* function.  */
@@ -2671,6 +2714,157 @@ avr_xload_libgcc_p (enum machine_mode mode)
 }
 
 
+/* Fixme: This is a hack because secondary reloads don't works as expected.
+
+   Find an unused d-register to be used as scratch in INSN.
+   EXCLUDE is either NULL_RTX or some register. In the case where EXCLUDE
+   is a register, skip all possible return values that overlap EXCLUDE.
+   The policy for the returned register is similar to that of
+   `reg_unused_after', i.e. the returned register may overlap the SET_DEST
+   of INSN.
+
+   Return a QImode d-register or NULL_RTX if nothing found.  */
+
+static rtx
+avr_find_unused_d_reg (rtx insn, rtx exclude)
+{
+  int regno;
+  bool isr_p = (avr_interrupt_function_p (current_function_decl)
+                || avr_signal_function_p (current_function_decl));
+
+  for (regno = 16; regno < 32; regno++)
+    {
+      rtx reg = all_regs_rtx[regno];
+      
+      if ((exclude
+           && reg_overlap_mentioned_p (exclude, reg))
+          || fixed_regs[regno])
+        {
+          continue;
+        }
+
+      /* Try non-live register */
+
+      if (!df_regs_ever_live_p (regno)
+          && (TREE_THIS_VOLATILE (current_function_decl)
+              || cfun->machine->is_OS_task
+              || cfun->machine->is_OS_main
+              || (!isr_p && call_used_regs[regno])))
+        {
+          return reg;
+        }
+
+      /* Any live register can be used if it is unused after.
+         Prologue/epilogue will care for it as needed.  */
+      
+      if (df_regs_ever_live_p (regno)
+          && reg_unused_after (insn, reg))
+        {
+          return reg;
+        }
+    }
+
+  return NULL_RTX;
+}
+
+
+/* Helper function for the next function in the case where only restricted
+   version of LPM instruction is available.  */
+
+static const char*
+avr_out_lpm_no_lpmx (rtx insn, rtx *xop, int *plen)
+{
+  rtx dest = xop[0];
+  rtx addr = xop[1];
+  int n_bytes = GET_MODE_SIZE (GET_MODE (dest));
+  int regno_dest;
+
+  regno_dest = REGNO (dest);
+
+  /* The implicit target register of LPM.  */
+  xop[3] = lpm_reg_rtx;
+
+  switch (GET_CODE (addr))
+    {
+    default:
+      gcc_unreachable();
+
+    case REG:
+
+      gcc_assert (REG_Z == REGNO (addr));
+
+      switch (n_bytes)
+        {
+        default:
+          gcc_unreachable();
+
+        case 1:
+          avr_asm_len ("%4lpm", xop, plen, 1);
+
+          if (regno_dest != LPM_REGNO)
+            avr_asm_len ("mov %0,%3", xop, plen, 1);
+
+          return "";
+
+        case 2:
+          if (REGNO (dest) == REG_Z)
+            return avr_asm_len ("%4lpm"      CR_TAB
+                                "push %3"    CR_TAB
+                                "adiw %2,1"  CR_TAB
+                                "%4lpm"      CR_TAB
+                                "mov %B0,%3" CR_TAB
+                                "pop %A0", xop, plen, 6);
+          
+          avr_asm_len ("%4lpm"      CR_TAB
+                       "mov %A0,%3" CR_TAB
+                       "adiw %2,1"  CR_TAB
+                       "%4lpm"      CR_TAB
+                       "mov %B0,%3", xop, plen, 5);
+                
+          if (!reg_unused_after (insn, addr))
+            avr_asm_len ("sbiw %2,1", xop, plen, 1);
+          
+          break; /* 2 */
+        }
+      
+      break; /* REG */
+
+    case POST_INC:
+
+      gcc_assert (REG_Z == REGNO (XEXP (addr, 0))
+                  && n_bytes <= 4);
+
+      if (regno_dest == LPM_REGNO)
+        avr_asm_len ("%4lpm"      CR_TAB
+                     "adiw %2,1", xop, plen, 2);
+      else
+        avr_asm_len ("%4lpm"      CR_TAB
+                     "mov %A0,%3" CR_TAB
+                     "adiw %2,1", xop, plen, 3);
+
+      if (n_bytes >= 2)
+        avr_asm_len ("%4lpm"      CR_TAB
+                     "mov %B0,%3" CR_TAB
+                     "adiw %2,1", xop, plen, 3);
+
+      if (n_bytes >= 3)
+        avr_asm_len ("%4lpm"      CR_TAB
+                     "mov %C0,%3" CR_TAB
+                     "adiw %2,1", xop, plen, 3);
+
+      if (n_bytes >= 4)
+        avr_asm_len ("%4lpm"      CR_TAB
+                     "mov %D0,%3" CR_TAB
+                     "adiw %2,1", xop, plen, 3);
+
+      break; /* POST_INC */
+      
+    } /* switch CODE (addr) */
+      
+  return "";
+}
+
+
 /* If PLEN == NULL: Ouput instructions to load a value from a memory location
    OP[1] in AS1 to register OP[0].
    If PLEN != 0 set *PLEN to the length in words of the instruction sequence.
@@ -2679,11 +2873,13 @@ avr_xload_libgcc_p (enum machine_mode mode)
 static const char*
 avr_out_lpm (rtx insn, rtx *op, int *plen)
 {
-  rtx xop[3];
+  rtx xop[7];
   rtx dest = op[0];
   rtx src = SET_SRC (single_set (insn));
   rtx addr;
   int n_bytes = GET_MODE_SIZE (GET_MODE (dest));
+  int regno_dest;
+  int segment;
   RTX_CODE code;
   addr_space_t as = MEM_ADDR_SPACE (src);
 
@@ -2704,18 +2900,56 @@ avr_out_lpm (rtx insn, rtx *op, int *plen)
   gcc_assert (REG_P (dest));
   gcc_assert (REG == code || POST_INC == code);
 
-  /* Only 1-byte moves from __flash are representes as open coded
-     mov insns.  All other loads from flash are not handled here but
-     by some UNSPEC instead, see respective FIXME in machine description.  */
-  
-  gcc_assert (as == ADDR_SPACE_FLASH);
-  gcc_assert (n_bytes == 1);
-
   xop[0] = dest;
-  xop[1] = lpm_addr_reg_rtx;
-  xop[2] = lpm_reg_rtx;
+  xop[1] = addr;
+  xop[2] = lpm_addr_reg_rtx;
+  xop[4] = xstring_empty;
+  xop[5] = tmp_reg_rtx;
+  xop[6] = XEXP (rampz_rtx, 0);
 
-  switch (code)
+  regno_dest = REGNO (dest);
+
+  segment = avr_addrspace[as].segment;
+
+  /* Set RAMPZ as needed.  */
+
+  if (segment)
+    {
+      xop[4] = GEN_INT (segment);
+      xop[3] = avr_find_unused_d_reg (insn, lpm_addr_reg_rtx);
+
+      if (xop[3] != NULL_RTX)
+        {
+          avr_asm_len ("ldi %3,%4" CR_TAB
+                       "out %i6,%3", xop, plen, 2);
+        }
+      else if (segment == 1)
+        {
+          avr_asm_len ("clr %5" CR_TAB
+                       "inc %5" CR_TAB
+                       "out %i6,%5", xop, plen, 3);
+        }
+      else
+        {
+          avr_asm_len ("mov %5,%2"         CR_TAB
+                       "ldi %2,%4"         CR_TAB
+                       "out %i6,%2"  CR_TAB
+                       "mov %2,%5", xop, plen, 4);
+        }
+      
+      xop[4] = xstring_e;
+
+      if (!AVR_HAVE_ELPMX)
+        return avr_out_lpm_no_lpmx (insn, xop, plen);
+    }
+  else if (!AVR_HAVE_LPMX)
+    {
+      return avr_out_lpm_no_lpmx (insn, xop, plen);
+    }
+
+  /* We have [E]LPMX: Output reading from Flash the comfortable way.  */
+
+  switch (GET_CODE (addr))
     {
     default:
       gcc_unreachable();
@@ -2723,105 +2957,85 @@ avr_out_lpm (rtx insn, rtx *op, int *plen)
     case REG:
 
       gcc_assert (REG_Z == REGNO (addr));
-      
-      return AVR_HAVE_LPMX
-        ? avr_asm_len ("lpm %0,%a1", xop, plen, 1)
-        : avr_asm_len ("lpm" CR_TAB
-                       "mov %0,%2", xop, plen, 2);
-      
-    case POST_INC:
-      
-      gcc_assert (REG_Z == REGNO (XEXP (addr, 0)));
 
-      return AVR_HAVE_LPMX
-        ? avr_asm_len ("lpm %0,%a1+", xop, plen, 1)
-        : avr_asm_len ("lpm"        CR_TAB
-                       "adiw %1, 1" CR_TAB
-                       "mov %0,%2", xop, plen, 3);
-    }
+      switch (n_bytes)
+        {
+        default:
+          gcc_unreachable();
 
-  return "";
-}
+        case 1:
+          return avr_asm_len ("%4lpm %0,%a2", xop, plen, 1);
 
+        case 2:
+          if (REGNO (dest) == REG_Z)
+            return avr_asm_len ("%4lpm %5,%a2+" CR_TAB
+                                "%4lpm %B0,%a2" CR_TAB
+                                "mov %A0,%5", xop, plen, 3);
+          else
+            {
+              avr_asm_len ("%4lpm %A0,%a2+" CR_TAB
+                           "%4lpm %B0,%a2", xop, plen, 2);
+                
+              if (!reg_unused_after (insn, addr))
+                avr_asm_len ("sbiw %2,1", xop, plen, 1);
+            }
+          
+          break; /* 2 */
 
-/* If PLEN == NULL: Ouput instructions to load $0 with a value from
-   flash address $1:Z.  If $1 = 0 we can use LPM to read, otherwise
-   use ELPM.
-   If PLEN != 0 set *PLEN to the length in words of the instruction sequence.
-   Return "".  */
+        case 3:
 
-const char*
-avr_load_lpm (rtx insn, rtx *op, int *plen)
-{
-  rtx xop[4];
-  int n, n_bytes = GET_MODE_SIZE (GET_MODE (op[0]));
-  rtx xsegment = op[1];
-  bool clobber_z = PARALLEL == GET_CODE (PATTERN (insn));
-  bool r30_in_tmp = false;
-  
-  if (plen)
-    *plen = 0;
-  
-  xop[1] = lpm_addr_reg_rtx;
-  xop[2] = lpm_reg_rtx;
-  xop[3] = xstring_empty;
-  
-  /* Set RAMPZ as needed.  */
-  
-  if (REG_P (xsegment))
-    {
-      avr_asm_len ("out __RAMPZ__,%0", &xsegment, plen, 1);
-      xop[3] = xstring_e;
-    }
-  
-  /* Load the individual bytes from LSB to MSB.  */
-  
-  for (n = 0; n < n_bytes; n++)
-    {
-      xop[0] = all_regs_rtx[REGNO (op[0]) + n];
+          avr_asm_len ("%4lpm %A0,%a2+" CR_TAB
+                       "%4lpm %B0,%a2+" CR_TAB
+                       "%4lpm %C0,%a2", xop, plen, 3);
+                
+          if (!reg_unused_after (insn, addr))
+            avr_asm_len ("sbiw %2,2", xop, plen, 1);
+
+          break; /* 3 */
       
-      if ((CONST_INT_P (xsegment) && AVR_HAVE_LPMX)
-          || (REG_P (xsegment) && AVR_HAVE_ELPMX))
-        {
-          if (n == n_bytes-1)
-            avr_asm_len ("%3lpm %0,%a1", xop, plen, 1);
-          else if (REGNO (xop[0]) == REG_Z)
+        case 4:
+
+          avr_asm_len ("%4lpm %A0,%a2+" CR_TAB
+                       "%4lpm %B0,%a2+", xop, plen, 2);
+          
+          if (REGNO (dest) == REG_Z - 2)
+            return avr_asm_len ("%4lpm %5,%a2+" CR_TAB
+                                "%4lpm %C0,%a2"          CR_TAB
+                                "mov %D0,%5", xop, plen, 3);
+          else
             {
-              avr_asm_len ("%3lpm %2,%a1+", xop, plen, 1);
-              r30_in_tmp = true;
+              avr_asm_len ("%4lpm %C0,%a2+" CR_TAB
+                           "%4lpm %D0,%a2", xop, plen, 2);
+                
+              if (!reg_unused_after (insn, addr))
+                avr_asm_len ("sbiw %2,3", xop, plen, 1);
             }
-          else
-            avr_asm_len ("%3lpm %0,%a1+", xop, plen, 1);
-        }
-      else
-        {
-          gcc_assert (clobber_z);
-          
-          avr_asm_len ("%3lpm" CR_TAB
-                       "mov %0,%2", xop, plen, 2);
 
-          if (n != n_bytes-1)
-            avr_asm_len ("adiw %1,1", xop, plen, 1);
-        }
-    }
-  
-  if (r30_in_tmp)
-    avr_asm_len ("mov %1,%2", xop, plen, 1);
-  
-  if (!clobber_z
-      && n_bytes > 1
-      && !reg_unused_after (insn, lpm_addr_reg_rtx)
-      && !reg_overlap_mentioned_p (op[0], lpm_addr_reg_rtx))
-    {
-      xop[2] = GEN_INT (n_bytes-1);
-      avr_asm_len ("sbiw %1,%2", xop, plen, 1);
-    }
-  
-  if (REG_P (xsegment) && AVR_HAVE_RAMPD)
+          break; /* 4 */
+        } /* n_bytes */
+      
+      break; /* REG */
+
+    case POST_INC:
+
+      gcc_assert (REG_Z == REGNO (XEXP (addr, 0))
+                  && n_bytes <= 4);
+
+      avr_asm_len                    ("%4lpm %A0,%a2+", xop, plen, 1);
+      if (n_bytes >= 2)  avr_asm_len ("%4lpm %B0,%a2+", xop, plen, 1);
+      if (n_bytes >= 3)  avr_asm_len ("%4lpm %C0,%a2+", xop, plen, 1);
+      if (n_bytes >= 4)  avr_asm_len ("%4lpm %D0,%a2+", xop, plen, 1);
+
+      break; /* POST_INC */
+
+    } /* switch CODE (addr) */
+
+  if (xop[4] == xstring_e && AVR_HAVE_RAMPD)
     {
       /* Reset RAMPZ to 0 so that EBI devices don't read garbage from RAM */
-      
-      avr_asm_len ("out __RAMPZ__,__zero_reg__", xop, plen, 1);
+
+      xop[0] = zero_reg_rtx;
+      avr_asm_len ("out %i6,%0", xop, plen, 1);
     }
 
   return "";
@@ -2857,7 +3071,7 @@ avr_out_xload (rtx insn ATTRIBUTE_UNUSED, rtx *op, int *plen)
 
 
 const char*
-output_movqi (rtx insn, rtx operands[], int *real_l)
+output_movqi (rtx insn, rtx operands[], int *plen)
 {
   rtx dest = operands[0];
   rtx src = operands[1];
@@ -2865,32 +3079,29 @@ output_movqi (rtx insn, rtx operands[], int *real_l)
   if (avr_mem_flash_p (src)
       || avr_mem_flash_p (dest))
     {
-      return avr_out_lpm (insn, operands, real_l);
+      return avr_out_lpm (insn, operands, plen);
     }
 
-  if (real_l)
-    *real_l = 1;
-  
   gcc_assert (1 == GET_MODE_SIZE (GET_MODE (dest)));
 
   if (REG_P (dest))
     {
       if (REG_P (src)) /* mov r,r */
-	{
-	  if (test_hard_reg_class (STACK_REG, dest))
-	    return "out %0,%1";
-	  else if (test_hard_reg_class (STACK_REG, src))
-	    return "in %0,%1";
-	  
-	  return "mov %0,%1";
-	}
+        {
+          if (test_hard_reg_class (STACK_REG, dest))
+            return avr_asm_len ("out %0,%1", operands, plen, -1);
+          else if (test_hard_reg_class (STACK_REG, src))
+            return avr_asm_len ("in %0,%1", operands, plen, -1);
+          
+          return avr_asm_len ("mov %0,%1", operands, plen, -1);
+        }
       else if (CONSTANT_P (src))
         {
-          output_reload_in_const (operands, NULL_RTX, real_l, false);
+          output_reload_in_const (operands, NULL_RTX, plen, false);
           return "";
         }
       else if (MEM_P (src))
-	return out_movqi_r_mr (insn, operands, real_l); /* mov r,m */
+        return out_movqi_r_mr (insn, operands, plen); /* mov r,m */
     }
   else if (MEM_P (dest))
     {
@@ -2899,8 +3110,9 @@ output_movqi (rtx insn, rtx operands[], int *real_l)
       xop[0] = dest;
       xop[1] = src == CONST0_RTX (GET_MODE (dest)) ? zero_reg_rtx : src;
 
-      return out_movqi_mr_r (insn, xop, real_l);
+      return out_movqi_mr_r (insn, xop, plen);
     }
+
   return "";
 }
 
@@ -7314,7 +7526,6 @@ adjust_insn_length (rtx insn, int len)
     case ADJUST_LEN_MOV32: output_movsisf (insn, op, &len); break;
     case ADJUST_LEN_MOVMEM: avr_out_movmem (insn, op, &len); break;
     case ADJUST_LEN_XLOAD: avr_out_xload (insn, op, &len); break;
-    case ADJUST_LEN_LOAD_LPM: avr_load_lpm (insn, op, &len); break;
 
     case ADJUST_LEN_SFRACT: avr_out_fract (insn, op, true, &len); break;
     case ADJUST_LEN_UFRACT: avr_out_fract (insn, op, false, &len); break;
@@ -10337,8 +10548,7 @@ avr_addr_space_pointer_mode (addr_space_t as)
 static bool
 avr_reg_ok_for_pgm_addr (rtx reg, bool strict)
 {
-  if (!REG_P (reg))
-    return false;
+  gcc_assert (REG_P (reg));
 
   if (strict)
     {
@@ -11710,6 +11920,9 @@ avr_fold_builtin (tree fndecl, int n_args ATTRIBUTE_UNUSED, tree *arg,
 #undef  TARGET_MODE_DEPENDENT_ADDRESS_P
 #define TARGET_MODE_DEPENDENT_ADDRESS_P avr_mode_dependent_address_p
 
+#undef  TARGET_SECONDARY_RELOAD
+#define TARGET_SECONDARY_RELOAD avr_secondary_reload
+
 #undef  TARGET_PRINT_OPERAND
 #define TARGET_PRINT_OPERAND avr_print_operand
 #undef  TARGET_PRINT_OPERAND_ADDRESS

gcc/config/avr/avr.md

@@ -63,7 +63,6 @@
   [UNSPEC_STRLEN
    UNSPEC_MOVMEM
    UNSPEC_INDEX_JMP
-   UNSPEC_LPM
    UNSPEC_FMUL
    UNSPEC_FMULS
    UNSPEC_FMULSU
@@ -142,7 +141,7 @@
    tsthi, tstpsi, tstsi, compare, compare64, call,
    mov8, mov16, mov24, mov32, reload_in16, reload_in24, reload_in32,
    ufract, sfract,
-   xload, movmem, load_lpm,
+   xload, movmem,
    ashlqi, ashrqi, lshrqi,
    ashlhi, ashrhi, lshrhi,
    ashlsi, ashrsi, lshrsi,
@@ -393,60 +392,57 @@
 ;;========================================================================
 ;; Move stuff around
 
-;; Represent a load from __flash that needs libgcc support as UNSPEC.
-;; This is legal because we read from non-changing memory.
-;; For rationale see the FIXME below.
-
-;; "load_psi_libgcc"    
-;; "load_si_libgcc"    
-;; "load_sf_libgcc"    
-(define_insn "load_<mode>_libgcc"
-  [(set (reg:MOVMODE 22)
-        (unspec:MOVMODE [(reg:HI REG_Z)]
-                        UNSPEC_LPM))]
-  ""
-  {
-    rtx n_bytes = GEN_INT (GET_MODE_SIZE (<MODE>mode));
-    output_asm_insn ("%~call __load_%0", &n_bytes);
-    return "";
-  }
-  [(set_attr "type" "xcall")
-   (set_attr "cc" "clobber")])
-
-
-;; Similar for inline reads from flash.  We use UNSPEC instead
-;; of MEM for the same reason as above: PR52543.
-;; $1 contains the memory segment.
-
-(define_insn "load_<mode>"
-  [(set (match_operand:MOVMODE 0 "register_operand" "=r")
-        (unspec:MOVMODE [(reg:HI REG_Z)
-                         (match_operand:QI 1 "reg_or_0_operand" "rL")]
-                        UNSPEC_LPM))]
-  "(CONST_INT_P (operands[1]) && AVR_HAVE_LPMX)
-   || (REG_P (operands[1]) && AVR_HAVE_ELPMX)"
+;; Secondary input reload from non-generic 16-bit address spaces
+(define_insn "reload_in<mode>"
+  [(set (match_operand:MOVMODE 0 "register_operand"   "=r")
+        (match_operand:MOVMODE 1 "memory_operand"      "m"))
+   (clobber (match_operand:QI 2 "d_register_operand"  "=d"))]
+  "MEM_P (operands[1])
+   && !ADDR_SPACE_GENERIC_P (MEM_ADDR_SPACE (operands[1]))"
   {
-    return avr_load_lpm (insn, operands, NULL);
+    return output_movqi (insn, operands, NULL);
   }
-  [(set_attr "adjust_len" "load_lpm")
+  [(set_attr "adjust_len" "mov8")
    (set_attr "cc" "clobber")])
 
 
-;; Similar to above for the complementary situation when there is no [E]LPMx.
-;; Clobber Z in that case.
+;; "loadqi_libgcc"
+;; "loadhi_libgcc"
+;; "loadpsi_libgcc"    
+;; "loadsi_libgcc"    
+;; "loadsf_libgcc"    
+(define_expand "load<mode>_libgcc"
+  [(set (match_dup 3)
+        (match_dup 2))
+   (set (reg:MOVMODE 22)
+        (match_operand:MOVMODE 1 "memory_operand" ""))
+   (set (match_operand:MOVMODE 0 "register_operand" "")
+        (reg:MOVMODE 22))]
+  "avr_load_libgcc_p (operands[1])"
+  {
+    operands[3] = gen_rtx_REG (HImode, REG_Z);
+    operands[2] = force_operand (XEXP (operands[1], 0), NULL_RTX);
+    operands[1] = replace_equiv_address (operands[1], operands[3]);
+    set_mem_addr_space (operands[1], ADDR_SPACE_FLASH);
+  })
 
-(define_insn "load_<mode>_clobber"
-  [(set (match_operand:MOVMODE 0 "register_operand" "=r")
-        (unspec:MOVMODE [(reg:HI REG_Z)
-                         (match_operand:QI 1 "reg_or_0_operand" "rL")]
-                        UNSPEC_LPM))
-   (clobber (reg:HI REG_Z))]
-  "!((CONST_INT_P (operands[1]) && AVR_HAVE_LPMX)
-     || (REG_P (operands[1]) && AVR_HAVE_ELPMX))"
+;; "load_qi_libgcc"
+;; "load_hi_libgcc"
+;; "load_psi_libgcc"    
+;; "load_si_libgcc"    
+;; "load_sf_libgcc"    
+(define_insn "load_<mode>_libgcc"
+  [(set (reg:MOVMODE 22)
+        (match_operand:MOVMODE 0 "memory_operand" "m,m"))]
+  "avr_load_libgcc_p (operands[0])
+   && REG_P (XEXP (operands[0], 0))
+   && REG_Z == REGNO (XEXP (operands[0], 0))"
   {
-    return avr_load_lpm (insn, operands, NULL);
+    operands[0] = GEN_INT (GET_MODE_SIZE (<MODE>mode));
+    return "%~call __load_%0";
   }
-  [(set_attr "adjust_len" "load_lpm")
+  [(set_attr "length" "1,2")
+   (set_attr "isa" "rjmp,jmp")
    (set_attr "cc" "clobber")])
 
 
@@ -464,6 +460,10 @@
   "&& 1"
   [(clobber (const_int 0))]
   {
+    /* ; Split away the high part of the address.  GCC's register allocator
+       ; in not able to allocate segment registers and reload the resulting
+       ; expressions.  Notice that no address register can hold a PSImode.  */
+
     rtx insn, addr = XEXP (operands[1], 0);
     rtx hi8 = gen_reg_rtx (QImode);
     rtx reg_z = gen_rtx_REG (HImode, REG_Z);
@@ -583,72 +583,29 @@
         operands[1] = src = copy_to_mode_reg (<MODE>mode, src);
       }
 
-  if (avr_mem_memx_p (src))
-    {
-      rtx addr = XEXP (src, 0);
-
-      if (!REG_P (addr))
-        src = replace_equiv_address (src, copy_to_mode_reg (PSImode, addr));
-
-      if (!avr_xload_libgcc_p (<MODE>mode))
-        /* ; No <mode> here because gen_xload8<mode>_A only iterates over ALL1.
-           ; insn-emit does not depend on the mode, it' all about operands.  */
-        emit_insn (gen_xload8qi_A (dest, src));
-      else
-        emit_insn (gen_xload<mode>_A (dest, src));
-
-      DONE;
-    }
+    if (avr_mem_memx_p (src))
+      {
+        rtx addr = XEXP (src, 0);
 
-    /* For old devices without LPMx, prefer __flash loads per libcall.  */
+        if (!REG_P (addr))
+          src = replace_equiv_address (src, copy_to_mode_reg (PSImode, addr));
 
-    if (avr_load_libgcc_p (src))
-      {
-        emit_move_insn (gen_rtx_REG (Pmode, REG_Z),
-                        force_reg (Pmode, XEXP (src, 0)));
+        if (!avr_xload_libgcc_p (<MODE>mode))
+          /* ; No <mode> here because gen_xload8<mode>_A only iterates over ALL1.
+             ; insn-emit does not depend on the mode, it's all about operands.  */
+          emit_insn (gen_xload8qi_A (dest, src));
+        else
+          emit_insn (gen_xload<mode>_A (dest, src));
 
-        emit_insn (gen_load_<mode>_libgcc ());
-        emit_move_insn (dest, gen_rtx_REG (<MODE>mode, 22));
         DONE;
       }
 
-    /* ; FIXME:  Hack around PR rtl-optimization/52543.
-       ; lower-subreg.c splits loads from the 16-bit address spaces which
-       ; causes code bloat because each load need his setting of RAMPZ.
-       ; Moreover, the split will happen in such a way that the loads don't
-       ; take advantage of POST_INC addressing.  Thus, we use UNSPEC to
-       ; represent these loads instead.  Notice that this is legitimate
-       ; because the memory content does not change:  Loads from the same
-       ; address will yield the same value.
-       ; POST_INC addressing would make the addresses mode_dependent and could
-       ; work around that PR, too.  However, notice that it is *not* legitimate
-       ; to expand to POST_INC at expand time:  The following passes assert
-       ; that pre-/post-modify addressing is introduced by .auto_inc_dec and
-       ; does not exist before that pass.  */
-
-    if (avr_mem_flash_p (src)
-        && (GET_MODE_SIZE (<MODE>mode) > 1
-            || MEM_ADDR_SPACE (src) != ADDR_SPACE_FLASH))
+    if (avr_load_libgcc_p (src))
       {
-        rtx xsegment = GEN_INT (avr_addrspace[MEM_ADDR_SPACE (src)].segment);
-        if (!AVR_HAVE_ELPM)
-          xsegment = const0_rtx;
-        if (xsegment != const0_rtx)
-          xsegment = force_reg (QImode, xsegment);
-
-        emit_move_insn (gen_rtx_REG (Pmode, REG_Z),
-                        force_reg (Pmode, XEXP (src, 0)));
-
-        if ((CONST_INT_P (xsegment) && AVR_HAVE_LPMX)
-            || (REG_P (xsegment) && AVR_HAVE_ELPMX))
-          emit_insn (gen_load_<mode> (dest, xsegment));
-        else
-          emit_insn (gen_load_<mode>_clobber (dest, xsegment));
+        /* For the small devices, do loads per libgcc call.  */
+        emit_insn (gen_load<mode>_libgcc (dest, src));
         DONE;
       }
-
-    /* ; The only address-space for which we use plain MEM and reload
-       ; machinery are 1-byte loads from __flash.  */
   })
 
 ;;========================================================================
@@ -798,6 +755,40 @@
     operands[5] = gen_rtx_REG (HImode, REGNO (operands[3]));
   })
 
+;; For LPM loads from AS1 we split 
+;;    R = *Z
+;; to
+;;    R = *Z++
+;;    Z = Z - sizeof (R)
+;;
+;; so that the second instruction can be optimized out.
+
+(define_split ; "split-lpmx"
+  [(set (match_operand:HISI 0 "register_operand" "")
+        (match_operand:HISI 1 "memory_operand" ""))]
+  "reload_completed
+   && AVR_HAVE_LPMX"
+  [(set (match_dup 0)
+        (match_dup 2))
+   (set (match_dup 3)
+        (plus:HI (match_dup 3)
+                 (match_dup 4)))]
+  {
+     rtx addr = XEXP (operands[1], 0);
+
+     if (!avr_mem_flash_p (operands[1])
+         || !REG_P (addr)
+         || reg_overlap_mentioned_p (addr, operands[0]))
+       {
+         FAIL;
+       }
+
+    operands[2] = replace_equiv_address (operands[1],
+                                         gen_rtx_POST_INC (Pmode, addr));
+    operands[3] = addr;
+    operands[4] = gen_int_mode (-GET_MODE_SIZE (<MODE>mode), HImode);
+  })
+
 ;;==========================================================================
 ;; xpointer move (24 bit)