re PR middle-end/24912 (m68k build failure: ICE: in reload_cse_simplify_operands)

	PR middle-end/24912
	PR middle-end/24750
	* reload.c (find_reloads_address_1): Mention dependency on
	gen_reload.
	* reload1.c (gen_reload): For IN with an unary operation, try
	moving inner expression to OUT if trivial SET is not valid.
	Confirm that the result is valid.  Move common code block into...
	(emit_insn_if_valid_for_reload): New function.

From-SVN: r107231

gcc/ChangeLog

+2005-11-19  Hans-Peter Nilsson  <hp@axis.com>
+
+	PR middle-end/24912
+	PR middle-end/24750
+	* reload.c (find_reloads_address_1): Mention dependency on
+	gen_reload.
+	* reload1.c (gen_reload): For IN with an unary operation, try
+	moving inner expression to OUT if trivial SET is not valid.
+	Confirm that the result is valid.  Move common code block into...
+	(emit_insn_if_valid_for_reload): New function.
+
 2005-11-19  Richard Guenther  <rguenther@suse.de>
 
 	* fold-const.c (fold_indirect_ref_1): Make sure we fold

gcc/reload.c

@@ -5311,7 +5311,9 @@ update_auto_inc_notes (rtx insn ATTRIBUTE_UNUSED, int regno ATTRIBUTE_UNUSED,
    occurs as part of an address.
    Also, this is not fully machine-customizable; it works for machines
    such as VAXen and 68000's and 32000's, but other possible machines
-   could have addressing modes that this does not handle right.  */
+   could have addressing modes that this does not handle right.
+   If you add push_reload calls here, you need to make sure gen_reload
+   handles those cases gracefully.  */
 
 static int
 find_reloads_address_1 (enum machine_mode mode, rtx x, int context,

gcc/reload1.c

@@ -437,6 +437,7 @@ static void add_auto_inc_notes (rtx, rtx);
 static void copy_eh_notes (rtx, rtx);
 static int reloads_conflict (int, int);
 static rtx gen_reload (rtx, rtx, int, enum reload_type);
+static rtx emit_insn_if_valid_for_reload (rtx);
 
 /* Initialize the reload pass once per compilation.  */
 
@@ -7449,6 +7450,32 @@ emit_reload_insns (struct insn_chain *chain)
   IOR_HARD_REG_SET (reg_reloaded_dead, reg_reloaded_died);
 }
 
+/* Go through the motions to emit INSN and test if it is strictly valid.
+   Return the emitted insn if valid, else return NULL.  */
+
+static rtx
+emit_insn_if_valid_for_reload (rtx insn)
+{
+  rtx last = get_last_insn ();
+  int code;
+
+  insn = emit_insn (insn);
+  code = recog_memoized (insn);
+
+  if (code >= 0)
+    {
+      extract_insn (insn);
+      /* We want constrain operands to treat this insn strictly in its
+	 validity determination, i.e., the way it would after reload has
+	 completed.  */
+      if (constrain_operands (1))
+	return insn;
+    }
+
+  delete_insns_since (last);
+  return NULL;
+}
+
 /* Emit code to perform a reload from IN (which may be a reload register) to
    OUT (which may also be a reload register).  IN or OUT is from operand
    OPNUM with reload type TYPE.
@@ -7485,6 +7512,12 @@ gen_reload (rtx out, rtx in, int opnum, enum reload_type type)
      trying to emit a single insn to perform the add.  If it is not valid,
      we use a two insn sequence.
 
+     Or we can be asked to reload an unary operand that was a fragment of
+     an addressing mode, into a register.  If it isn't recognized as-is,
+     we try making the unop operand and the reload-register the same:
+     (set reg:X (unop:X expr:Y))
+     -> (set reg:Y expr:Y) (set reg:X (unop:X reg:Y)).
+
      Finally, we could be called to handle an 'o' constraint by putting
      an address into a register.  In that case, we first try to do this
      with a named pattern of "reload_load_address".  If no such pattern
@@ -7542,20 +7575,9 @@ gen_reload (rtx out, rtx in, int opnum, enum reload_type type)
       if (op0 != XEXP (in, 0) || op1 != XEXP (in, 1))
 	in = gen_rtx_PLUS (GET_MODE (in), op0, op1);
 
-      insn = emit_insn (gen_rtx_SET (VOIDmode, out, in));
-      code = recog_memoized (insn);
-
-      if (code >= 0)
-	{
-	  extract_insn (insn);
-	  /* We want constrain operands to treat this insn strictly in
-	     its validity determination, i.e., the way it would after reload
-	     has completed.  */
-	  if (constrain_operands (1))
+      insn = emit_insn_if_valid_for_reload (gen_rtx_SET (VOIDmode, out, in));
+      if (insn)
 	return insn;
-	}
-
-      delete_insns_since (last);
 
       /* If that failed, we must use a conservative two-insn sequence.
 
@@ -7591,29 +7613,17 @@ gen_reload (rtx out, rtx in, int opnum, enum reload_type type)
       if (rtx_equal_p (op0, op1))
 	op1 = out;
 
-      insn = emit_insn (gen_add2_insn (out, op1));
-
-      /* If that failed, copy the address register to the reload register.
-	 Then add the constant to the reload register.  */
-
-      code = recog_memoized (insn);
-
-      if (code >= 0)
-	{
-	  extract_insn (insn);
-	  /* We want constrain operands to treat this insn strictly in
-	     its validity determination, i.e., the way it would after reload
-	     has completed.  */
-	  if (constrain_operands (1))
+      insn = emit_insn_if_valid_for_reload (gen_add2_insn (out, op1));
+      if (insn)
 	{
 	  /* Add a REG_EQUIV note so that find_equiv_reg can find it.  */
 	  REG_NOTES (insn)
 	    = gen_rtx_EXPR_LIST (REG_EQUIV, in, REG_NOTES (insn));
 	  return insn;
 	}
-	}
 
-      delete_insns_since (last);
+      /* If that failed, copy the address register to the reload register.
+	 Then add the constant to the reload register.  */
 
       gen_reload (out, op1, opnum, type);
       insn = emit_insn (gen_add2_insn (out, op0));
@@ -7643,7 +7653,44 @@ gen_reload (rtx out, rtx in, int opnum, enum reload_type type)
       gen_reload (out, loc, opnum, type);
     }
 #endif
+  else if (REG_P (out) && UNARY_P (in))
+    {
+      rtx insn;
+      rtx op1;
+      rtx out_moded;
+      rtx set;
+
+      /* First, try a plain SET.  */
+      set = emit_insn_if_valid_for_reload (gen_rtx_SET (VOIDmode, out, in));
+      if (set)
+	return set;
+
+      /* If that failed, move the inner operand to the reload
+	 register, and try the same unop with the inner expression
+	 replaced with the reload register.  */
+      op1 = XEXP (in, 0);
+
+      if (GET_MODE (op1) != GET_MODE (out))
+	out_moded = gen_rtx_REG (GET_MODE (op1), REGNO (out));
+      else
+	out_moded = out;
+
+      gen_reload (out_moded, op1, opnum, type);
 
+      insn
+	= gen_rtx_SET (VOIDmode, out,
+		       gen_rtx_fmt_e (GET_CODE (in), GET_MODE (in),
+				      out_moded));
+      insn = emit_insn_if_valid_for_reload (insn);
+      if (insn)
+	{
+	  REG_NOTES (insn)
+	    = gen_rtx_EXPR_LIST (REG_EQUIV, in, REG_NOTES (insn));
+	  return insn;
+	}
+
+      fatal_insn ("Failure trying to reload:", set);
+    }
   /* If IN is a simple operand, use gen_move_insn.  */
   else if (OBJECT_P (in) || GET_CODE (in) == SUBREG)
     emit_insn (gen_move_insn (out, in));